Phẫu Thuật Gân Bàn Tay (Tendon Surgery of the Hand)

88
CHAPTER
9 
TREATMENT OF THE FLEXOR
TENDON SHEATH AND PULLEYS
Jin Bo Tang, MD
particular—has received great attention in efforts to
optimize the outcomes of flexor tendon surgery.
ANATOMY
The digital flexor sheath is a closed synovial system
extending from the distal part of the digits to the meta­
carpophalangeal (MCP) joint levels of the digits. The
sheath consists of membranous portions of continuous
synovial sheath (called simply the “sheath”), and con­
densed retinacular components (the “pulleys”). A layer
of thin, smooth, and continuous membrane covers the
inner surface of the entire sheath and pulleys. Pulleys
are segmentally located and overlie the membranous
lining. The pulleys include annular pulleys (condensed,
rigid, and heavier annular bands), cruciate pulleys
(filmy cruciform bands), and the transverse palmar apo­
neurosis pulley (Figure 9-1).1
In each of the four fingers, there are five annular
pulleys (A1, A2, A3, A4, and A5), three cruciate pulleys
(C1, C2, and C3), and one palmar aponeurosis (PA)
pulley.1-3 The A1, A3, and A5 pulleys originate from the
palmar plates of the MCP and proximal and distal inter­
phalangeal (PIP and DIP) joints, respectively. The A2
and A4 pulleys originate from the middle portion of the
proximal and middle phalanges, respectively. The broad­
est is the A2 pulley, which covers the proximal two-
thirds of the proximal phalanx and encompasses the
bifurcation of the flexor digitorum superficialis (FDS)
tendon. The A4 pulley is located at the middle of the
middle phalanx. The A2 and A4 pulleys are structurally
the most critically located and, functionally, the most
important.
The length of the A2 pulley is about 1.5 to 1.7 cm
and the length of the A4 pulley is about 0.5 to 0.7 cm
in the middle finger of an average adult. The diameter
of the flexor sheath is at its narrowest at the level of the
A4 pulley and in the middle and distal parts of the A2
pulley. The A2 and A4 pulleys appear as white con­
densed bands; they are easily recognizable, because
both are remarkably denser and more rigid than their
adjacent flexor sheath. The A1 pulley, with a length of
about 1.0 cm, is located proximal to the A2 pulley; in
some instances, both A1 and A2 pulleys merge to form
OUTLINE
The flexor sheath system consists of a continuous
synovial sheath and segmental pulleys. The pulleys are
arranged in either cruciform or annular patterns over­
lying the membranous synovial sheath. The synovial
sheath provides the tendons with a smooth gliding
bed and the pulleys strengthen the sheath and main­
tain the proper mechanics of tendon motion. The
digital sheath system is closed and compact, making
it structurally comparable to a compartment of the
extremities. The traumatized and edematous tendon
can be easily compressed by the tightly closed sheath,
resulting in poor tendon healing, adhesion formation,
and loss of integrity of the sheath.
The guiding principle in treating the sheath is not
to narrow the injured, or opened, sheath and not to
compress the repaired tendons. Closure of the injured,
or opened, synovial sheath is not necessary, unless
such openings are long. Venting of a part of the A2
pulley and the A4 pulley, under the condition of the
other annular pulleys and the remainder of the syno­
vial sheath being intact, improves outcomes and does
not produce a clinically significant functional distur­
bance. The length of such active release of the sheath–
pulley complex should not exceed 2 cm.
Pulley-release procedures should not be carried out
without thorough mastery of pulley anatomy and rec­
ognition of the borders of these pulleys during dissec­
tion. Releasing multiple pulleys (cruciate and annular)
or leaving a lengthy defect, or opening, in the synovial
sheath and pulley system is harmful and impairs
digital function. Losses of significant length of the
sheath or multiple pulleys should be reconstructed.
The synovial sheath and segmental pulleys are a
prominent feature of the flexor tendon system in the
hand. Because injury to the sheath occurs in all flexor
tendon lacerations in the digits and we cannot approach
the tendons without violating the sheath surgically, con­
siderable investigations have been devoted to this topic
over decades.1-33 The significance of proper treatment of
the sheath—the rigid and condensed annular pulleys in

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Chapter 9:  Treatment of the Flexor Tendon Sheath and Pulleys
In the finger, the A2 pulley is the strongest in respect
of preventing anterior displacement of the tendons and
is at the most critical location. The A2 and A4 pulleys
are most important in maintaining the biomechanics
of the tendon gliding, although the other sheath com­
ponents do contribute to the maintenance of tendon
mechanics. Absence of a series of pulleys will affect
tendon mechanics. Manske and Lesker2 investigated the
roles of the A2, A1, and PA pulleys and found that
absence of any two, or all three, pulleys resulted in
tendon bowstringing. Tang and Xie20 investigated the
roles of the A3, C1, and C2 pulleys and found that these
pulleys help to restrain tendon bowstringing.
In the thumb, the proximally located A1 pulley and
the oblique pulley are the most important functionally.
The distally located A2 pulley of the thumb is thin and
is relatively unimportant. Doyle and Blythe3 found sig­
nificant decrease in motion of the distal joint of the
thumb when both the A1 and the oblique pulleys were
removed, but loss of either alone did not noticeably
affect the motion of this joint.
HISTORICAL REVIEW
A review of the conceptual changes regarding roles and
treatments of the sheath, pulleys in particular, are pro­
vided by Elliot, together with his commentaries in the
Chapter 10. Here, Box 9-1 summarizes the work of other
groups that influenced our studies, the time sequence of
our investigations, and evolving philosophies, leading
to current treatment guidelines.4-29
INVESTIGATIONS
Over two decades, I have organized and conducted a
series of investigations to explore the basic science and
to develop clinical treatments relevant to the flexor
sheath and pulleys. My investigations proceeded after
starting with a study of the methods of sheath recon­
struction in 1988 under the instruction of an exemplary
hand surgeon, Professor Seichii Ishii.
My interest was developed in the studies of the
methods of sheath treatment and their effects on tendon
gliding, followed by an anatomical study of the flexor
pulleys. Over the past decade, I have been joined by a
group of capable colleagues in studying the effects of
pulleys and pulley incisions on tendon biomechanics
and tendon biology.
Investigation of Sheath Treatment—Excision,
Repair and Reconstruction
In the 1980s, there was an upsurge in awareness of the
importance of synovial nutrition of the tendon and in
attempts to restore the integrity of the injured synovial
sheath. My first study was on sheath excision, closure,
and enlargement plasty using a graft. However, the find­
ings did not support particular benefit from direct
closure of the opened sheath, but, instead, indicated
a compound pulley complex. The A3 pulley is located
palmar to the PIP joint, is short (0.3 cm) and difficult
to distinguish from the synovial sheath.
In the thumb, there are three pulleys (A1, oblique,
and A2) with no cruciate pulleys. The A1 pulley (0.7 to
0.9 cm in length) is located palmar to the MCP joint.
The oblique pulley (0.9 to 1.1 cm) spans the middle
and distal parts of the proximal phalanx. The A2 pulley
(0.8 to 1.0 cm) is close to the insertion of the flexor
pollicis longus (FPL) tendon.
FUNCTION
The synovial sheath offers a smooth gliding bed and
provides synovial nutrition to the tendons. Mechani­
cally, the pulleys serve to strengthen the sheath and hold
the flexor tendons close to phalanges and their joints.
The annular pulleys act as a fulcrum, optimizing the
mechanical efficiency of digital flexion. The more com­
pressible cruciate pulleys allow for digital flexion with
condensation of the fibro-osseous sheath at the inner
part of flexed fingers (called the “concertina effect”) (see
Figure 9-1). Both forms of pulley prevent anterior dis­
placement (i.e., bowstringing) of the tendon during
finger flexion.
Figure 9-1  The anatomy of the flexor pulleys and synovial
sheath of the fingers (A), with the finger flexed (B), and the
concertina effect on the sheath during finger flexion (C).
B
A
PA
A1
A2
C1
A3 C2
A4
pulleys
A1
A2
C1
A3
C2
A4
A2
C1 A3 C2 A4
A5
C3
A1
PA
Digital pulley system
C

90
Section 2:  Primary Flexor Tendon Surgery
1985:  Lister, in a review, advocated sheath closure and described the method to create sheath flaps to assess the tendon
and accommodate surgical repairs.4 This review had a great impact on later clinical practice of sheath closure.
1985:  Strauch and colleagues compared the results of sheath closure with vein grafts with sheath excision in chickens.
They found improved digital motion after restoration of sheath integrity.5
1986:  Peterson and Manske compared the mechanical and histologic outcomes of sheath repair and excision in a chicken
model. They concluded that closure of the flexor sheath does not improve tendon gliding.6,7
1987:  Saldana and colleagues compared surgical closure (42 fingers) and opening (48 fingers) of the sheath after tendon
repairs in zone 2 in a comparative perspective study. There was no statistical difference between the results of the patients
with the two treatments.8
1988:  Manske, in a review, stated, “It should be kept in mind that a water-tight closure of the tendon sheath may in fact
narrow the diameter of the fibro-osseous canal and reduce its volume.”9
1990:  Tang, Ishii, and Usui compared the mechanical and histological results of sheath repair, excision, and enlargement
sheath plasty by autogenous grafts using chickens. Tendon gliding was not improved after sheath closure, but was
improved after enlargement plasty. They considered that the fibro-osseous digital sheath is comparable to the fibro-
osseous muscle compartments in the extremities, and proposed a “digital sheath syndrome” to explain pathophysiology
in the tendon after tight sheath closure.10
1990:  Gelberman and colleagues compared sheath reconstruction and excision in canines treated by early motion reha­
bilitation, and substantiated that sheath repair—either by suture or graft—does not improve the biomechanical, biochemi­
cal or morphologic features of the tendons.11
1990:  Savage measured tendon excursion, profundus tendon flexion force, and tendon bowstringing using five cadaveric
hands after varying combined excisions of the annular pulleys. He stated, “In an otherwise intact digital fibrous flexor
sheath, A2 and A4 pulleys were no more important mechanically than the other pulleys.”12
1994:  Tang and colleagues reported that closure of the sheath did not improved tendon gliding in chickens at multiple
time-points of delayed primary repair.13
1995:  Tang studied the anatomy of the A2 pulley specifically, using cadaveric hands, by measuring the tendon excursion
after midline incisions through part of the A2 pulley, and the vertical and horizontal diameters of distal, middle, and proxi­
mal parts of this pulley. He proposed the partial release of the pulley and stated, “To improve tendon healing and gliding,
procedures for A2 pulley release, including incision of the critical portion to free tendon motion or enlargement of the A2
pulley, can be performed.”14
1996:  Tang, Shi, and Zhang examined the effects of sheath narrowing and enlargement on tendon excursions, healing,
and adhesions using chickens. They demonstrated that the diameter of the surgically repaired sheath exerts great influ­
ences on tendon function.15
1998:  Kwi, Ben, and Elliot reported the clinical results of zone 2 flexor tendon repairs in 185 fingers in 166 patients together
with lateral release of the A2 and A4 pulleys. They showed practicability of active partial release of these pulleys. They
stated, “It was necessary to vent the A4 pulley between 10 and 100% of its length in 71 (56%) of the fingers and to vent
the distal edge of the A2 pulley by 4 to 10 mm in 10 (8%) of the fingers.”16
1999:  Tang and colleagues reported 1-year follow-up of the finger motion after simple partial release through the one-half
to two-thirds portion along the midline of the A2 pulley or with enlargement pulley plasty in 16 fingers. No tendon bow­
stringing was noted. They advocated “partial release of the A2 pulley up to 1/2 or 2/3 lengths of the A2 pulley under the
condition that other pulleys are intact.”17
1998, 1999:  Tomaino, Mitsionis, and colleagues performed cadaveric studies to substantiate that partial release of the
A2 and complete release of the A4 pulley do not significantly alter tendon mechanics.18,19
2001:  Tang and Xie, in a cadaveric study, showed that loss of an A3 pulley does not affect tendon biomechanics, but cruci­
ate pulleys and synovial sheath restrain tendon bowstringing. They advise not creating lengthy sheath defects, given the
integrity of major annular pulleys.20
Box 9-1 Some Major Steps Toward Current Treatments of Sheath and Pulleys Over the Past 25 Years

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Chapter 9:  Treatment of the Flexor Tendon Sheath and Pulleys
explain the pathophysiological changes in the tendons
was proposed to describe the triad phenomena fre­
quently associated with tight closure of the sheath,
namely: (1) loss of integrity of the directly closed sheath;
(2) increased peritendinous adhesions; and (3) worsened
tendon healing. These considerations are further sup­
ported by a subsequent study to deliberately narrow the
sheath and compare this with direct closure of the
incised sheath, partially excised the sheath or sheath
enlargement by an interposition graft.15
Figure 9-2  Consequences after tight closure of the sheath
or pulleys.
DIGITAL SHEATH: A MINIATURE COMPARTMENT
Tight closure of the sheath/pulleys
Compress the edematous tendons
Digital sheath syndrome
• Poor tendon healing (ruptures)
• Adhesion formations
• Destruction of closed synovial sheath
Avoid compression to repaired tendons!
Tendons are edematous after surgery.
FDS
FDP
Sheath narrowing
that enlargement of the sheath accommodates tendon
gliding more effectively than direct closure of the sheath
after tendon repair.
In this study, we used 90 long toes of 45 white
Leghorn chickens to compare the effect of enlargement
sheath plasty—interposing a patch of grafted sheath
from the extensor retinaculum area into a longitudinal
opening of the sheath, without excising the digital
sheath—with two treatments: sheath excision or direct
sheath closure after longitudinal incision.10 Tendons in
zone 2 were completely cut and surgically repaired
either primarily or at the delayed primary stage (3 days
after tendon division).
We found that 6 weeks later, in toes with primary
repair, sheath enlargement produced greater tendon
excursion than sheath excision or closure, but no differ­
ence was found between the latter two treatments. In the
toes with delayed primary repair, the tendons with
sheath enlargement had the greatest gliding, and those
with the sheath closed directly had the worst gliding. The
sheath that had been closed during delayed primary
repair have dissolved among the extended adhesions.
Conclusions: We concluded that enlargement sheath
plasty by a graft improves tendon gliding. Direct closure
of the sheath does not improve tendon gliding, and may
in fact impair tendon gliding at the delayed primary
stage.10 We considered the digital sheath comparable
to the fibro-osseous compartments of the extremities
(Figure 9-2). A concept of “digital sheath syndrome” to
2002:  Elliot, in a review, highlighted the feasibility of pulley-venting. He stated: “In reality, … as the A2 pulley is of sufficient
length that one can excise any one-third of it to allow repair and free movement of the repair and still have a pulley which
is one or more centimetres in length, and thus, functional.” Regarding the sheath, he stated: “It is now our practice after
zone 2 repairs to simply lay the sheath back over the tendons without suturing, after adequate venting of the A2 and A4
pulleys to allow free running of the repairs.21
2002:  Amadio, Zhao, Paillard, and colleagues investigated gliding resistance of the FDP tendon after resection of one
slip of the FDS tendon and Kapandji pulley plasty, and found that both pulley plasty and resection of one slip of the FDS
reduce gliding resistance.22
2003, 2007: Tang, Xie, Xu, and colleagues investigated tendon repairs within and proximal to a major pulley using chick­
ens. Worse results of surgeries were noted in the pulley area.24 They compared the results of simple pulley incision, Kapandji
pulley plasty, and excision of one slip of the FDS and found no improvement of tendon gliding after Kapandji pulley plasty.25
2004:  Tanaka, Amadio, An, and colleagues investigated gliding resistance of the tendon and pulley strength after the A2
pulley was excised successively by 25%, 50%, and 75%. Their data support the clinical practice of partial pulley excision,
up to a limit of 50%.26
2007:  Tang, in a review, highlighted the critical roles of proper and sufficient release of critical annular pulleys in achieving
predicable functional recovery. He outlined precisely the lengths and areas to be release in different locations of injuries.
He considered that proper release of the pulley may be even more effective in reducing repair ruptures than use of a strong
repair.27
2009:  Cao and Tang compared the strength of the repaired tendon with the A2 pulley intact or vented at varying digital
flexion. They recorded that the strength decreased significantly when the pulley was intact.29 Rupture of the healing
tendons was significantly more frequent when the pulley was intact.28

92
Section 2:  Primary Flexor Tendon Surgery
Among 21 fingers with such grafts, 7 fingers were rated
excellent (33.3%), 11 good (52.4%), and 3 fair (14.3%).
No tendon rupture occurred.
Investigation of the Anatomy of the A2 Pulley
and Clinical Partial A2 Pulley Release
In 1993, I reviewed the results of flexor tendon repairs
in different subdivisions of the zone 2, and noted that
the worse outcomes were most frequently associated
with zone 2C (A2 pulley area) injuries. This finding
prompted me to specifically observe the A2 pulley
anatomy and the mechanics of FDS and FDP tendon
motion under the A2 pulley.
I dissected 40 fingers of 10 cadaveric hands. The
transverse and vertical diameters of the A2 pulley were
measured at its distal border, middle, and proximal
border.14 The excursions of the FDP tendons and
maximal finger flexion were measured after incision
through volar midline of the proximal half, and then,
the whole length of the A2 pulley.
Anatomically, the distal and middle parts of the A2
pulley are the narrowest. Movement of the FDP tendon
is restrained by both the A2 pulley and the FDS tendon
(Figures 9-3 and 9-4). Mechanically, given the integrity
of the other annular pulleys, incision of half of the A2
pulley resulted in only minimal (0.7%) loss of total
flexion of motion; complete division of the A2 pulley
Clinical application: Between 1989 and 1991, we
treated 21 fingers in 17 patients presenting with zone 2
tendon injuries and a graft was taken from the sheath
covering the extensors in the wrist or with a part of the
dorsal retinaculum to reconstruct and enlarge the trau­
matically defected sheath (Box 9-2).31 The size of the
graft was made greater than the size of the real defect.
Figure 9-3  The anatomy of flexor tendon zone 2C, i.e., the A2 pulley area. The gliding of the FDP tendon is restricted by
both the rigid and narrow A2 pulley and the bifurcating FDS tendon which surrounds the anterior, lateral, and dorsal aspects
of the FDP tendon. The presence of such a “double sheath” restricting motion of the FDP tendon is a unique anatomical
feature in this locality, which contributes to difficulties of surgery and recovery of tendon function after surgical repair.
A2
A2
FDS bifurcation
IID
IIC
IIB
Double sheath for FDP
Figure 9-4  The anatomy of the A2 pulley: changes of sheath diameter in the locality covered by and proximal to the A2 pulley.
FDS
FDS
CHANGES IN SHEATH DIAMETER: A2 PULLEY
FDP
FDS
FDS
FDP
FDP
FDS
FDP
FDS
Most narrow
Very restrictive
Most narrow
Very restrictive
Relatively large
Less restrictive
Relatively large
Less restrictive
Distal A2
Middle A2
Proximal A2
Proximal to A2
1993:  Tang, Ishii, and Zhang reported 21 fingers in 17
patients with enlargement sheath reconstruction using
autografts during delayed primary tendon repair in zone
2. No repair ruptures were noted in this case series.31
2005:  Bakhach and colleagues reported a new
procedure—flexor pulley Omega plasty, which consists
of releasing the lateral attachment of the pulley to
increase the internal volume (the flexor tendon gliding
space) in the A2 and A4 pulley localities. They consid­
ered that “this procedure respects the anato­mical con­
tinuity of the pulley and its mechanical properties.”31
2009, 2010:  Bunata and colleagues presented his
experimental data in cadavers32 and, subsequently, nine
fingers of primary pulley enlargement plasty using auto­
grafts.33 No repair ruptures were found.
Box 9-2  Some Major Clinical Reports of Case
Series of Sheath or Pulley Plasty Procedures

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Chapter 9:  Treatment of the Flexor Tendon Sheath and Pulleys
produces significantly worse tendon gliding and
increased work of digital flexion. Incision of the sheath
produces identical results, regardless of whether the
sheath is closed by a graft; (4) tendon gliding resistance
decreases substantially after release of the pulley in the
postoperative period; (5) tendon repair strength
increases significantly when the pulley is released com­
pared with the pulley intact; and (6) presence of an
intact A2 pulley contributes more substantially to
increase in the resistance to active tendon movement
than edematous subcutaneous tissue.
Clinical application: My colleagues and I have contin­
ued the practice of partial A2 pulley release thus far. I
further defined the length and location of the sheath
pulley which can be released without causing clinical
problems of tendon bowstringing.27 In this period, we
reviewed more than 40 cases of release of part of the A2
pulley or the A4 pulley. We did not detect tendon bow­
stringing sufficient to cause clinically perceivable func­
tional disturbances after partial and limited pulley
release procedures, given the integrity of the other
pulleys. Proper release of these pulleys, together with
strong surgical repairs, even without very strictly super­
vised postsurgical motion in our recent case series, led
to good or excellent recovery of finger flexion when the
tendon wounds were clean or could be converted to
clean wounds.
TREATMENT GUIDELINES
The guideline for treating the sheath is not to narrow the
sheath and not to compress the repaired tendons. Surgically,
priority should be given to avoiding narrowing of the
tendon gliding space, rather than complete restoration
of sheath integrity. Complete closure of the sheath is
insignificant to tendon function and, thus, is not a
necessity during primary tendon repair. During delayed
primary repair, sheath closure is usually not possible
due to sheath contracture. However, a lengthy defect in
the sheath would impair tendon mechanics and, thus,
should be avoided.
INDICATIONS AND OPERATIVE METHODS
Direct Closure
Direct closure of the sheath, usually performed with
interrupted 5-0 suture, may be indicated at primary
repair in a clean-cut wound without sheath defect. I
personally do not close the sheath if it appears likely
to be difficult, but do avoid leaving a lengthy sheath
opening or defect (greater than 2 cm). Possible benefits
of direct closure of the sheath may be avoiding catching
of the repaired tendons on the cut edges of the sheath
and avoiding invasion adhesions to the tendon repair
site. However, closure of the sheath is not necessary to
nutrition and healing of the tendon. Clinically, there is
no clear evidence of improvement of tendon gliding
resulted in a larger (2.3%) loss of flexion. Incision of part
of the A2 pulley did not lead to tendon bowstringing.14
Conclusions: The distal and middle parts of the A2
pulley are particularly restrictive to tendon gliding.
Partial A2 pulley release affects digital motion insignifi­
cantly and does not cause tendon bowstringing.14 Based
on the findings, I proposed procedures for partial release
of the A2 pulley to release compression of the repaired
tendon under the pulley.
Clinical application: From 1994, I started to partially
incise the A2 pulley along its volar midline when repair­
ing the tendons in this area; the length of the release
was either the distal or proximal half to two-thirds.
Before partial release of the A2 pulley, the other annular
pulleys were confirmed to be intact and uninjured. In
carrying out these A2 releases, a part of the A2 pulley
was always retained. In 1998, we examined the outcome
of 16 fingers with FDP tendon repairs and partial release
of the A2 pulley.15 No functionally disturbing tendon
bowstringing was noted after this procedure. Although,
from a rigorous viewpoint, the tendon would displace
after even minor releases of the pulley after incision
through its midline, such changes are insignificant clini­
cally and are well within the compensatory reserves of
the tendon system for normal function.
Investigations of the Effects of Integrity of
the A2 Pulley in Chicken Models and Partial
A2 and A4 Pulley Releases in Clinical Cases
Between 2000 and 2011, my colleagues and I studied (1)
different results of tendon repairs after tendon injuries
within, or proximal to, the A2 pulley; (2) the biome­
chanics and adhesions of tendons after repair of a single
slip of bifurcated FDS tendon, incision of the A2 pulley,
Kapandji pulley plasty, and direct pulley closure; (3)
tendon gliding and the work of digital flexion after
flexor tendon repair together with sheath enlargement
by a graft, sheath incision, or sheath closure with delib­
erate narrowing; (4) tendon gliding resistances in
tendon repairs with the pulley released and intact; (5)
tendon repair strengths with the pulley released and
intact; and (6) relative contribution of an intact A2
pulley and edematous subcutaneous tissue to resistance
to active tendon movement. All studies were carried out
in the chicken toe model and involved more than 260
chickens. The study methods were detailed in previous
reports.23-25,28,29
Conclusions: (1) tendon repairs located under the A2
pulley have significantly worse gliding excursion and
more adhesion formation than those proximal to the
pulley; (2) release of the A2 pulley or resection of one
slip of the FDS tendon produces greater tendon excur­
sions, smaller work of digital flexion and less adhesion
formation than closure of the pulley. Kapandji pulley
plasty does not improve tendon gliding more than a
simple pulley incision; (3) narrowing of the sheath

94
Section 2:  Primary Flexor Tendon Surgery
Figure 9-5  Proposed sites and lengths of sheath-pulley releases in primary or delayed primary flexor tendon repair in the
fingers, which allow access to the tendons and release constriction to tendon gliding, but do not produce loss of tendon
function due to tendon bowstringing.
A5
A4
Tendon laceration
Tendon laceration
Tendon laceration
Tendon laceration
Sheath-pulley release
Sheath-pulley release
Sheath-pulley release
Sheath-pulley release
A3
A2
A1
C1
C3
C2
after sheath closure. In delayed primary repair, sheath
contracture usually makes direct closure impossible.
Excision
Sheath excision has been a practice of hand surgeons for
decades and comes from the era when outside adhesions
were considered necessary to tendon healing. However,
it is equally appropriate, or even more appropriate, to
leave it unrepaired. I leave the sheath unrepaired in most
cases at primary repair but excise a part of an already
thickened, or contracted, sheath at delayed repair.
Sheath Reconstruction by Grafts
Sheath defects can be reconstructed by grafting a sheath
with extensor retinaculum.30,33 The graft, with the syno­
vial aspect facing the tendons, is sutured with 5-0 inter­
rupted sutures to the in situ sheath. In performing such
grafting, I emphasize that the graft size should be greater
than the size of the defect, to avoid potential compro­
mise to the repaired tendons. Sheath enlargement plasty
by a graft may decrease resistance to the tendon and act
as a barrier to adhesion invasion. If the laceration
extends over the entire length of the A2 pulley, such a
graft of extensor retinaculum may both improve gliding
and decrease tendon bowstringing.
In the early 1990s, I reconstructed digital sheath
defects by harvesting an autograft.30 During the last 10
years, I have not reconstructed sheath defects using graft
as I have changed to partially releasing the A2 pulley
together with part of the adjacent synovial sheath,
without recourse to grafts. Without this reconstructive
procedure, the surgery is simpler, and outcomes are
similar, in my experience.
Venting of the Major Pulleys
(such as the A2 and A4)
Venting a part of the A2 pulley or the entire A4 pulley
has been advocated by a number of surgeons to improve
gliding of the repaired tendons.14,16,21,34-36 Those reports
have shown that such venting does not lead to tendon
bowstringing, given the integrity of other parts of the
sheath, including the other annular pulleys.14,16,21,27,34-36
Venting of the most constrictive part of the pulley
substantially decreases gliding resistance and avoids
catching of a bulky repair on the pulley edge. Of par­
ticular note, several recent reports showed no repair
rupture in the cases that underwent venting of the major
pulleys.27,34-36
In my experience, given the integrity of the other
annular pulleys, the A2 pulley can be vented through
two-thirds of its length, either distally or proximally.
The A4 pulley can be vented entirely (Figures 9-5
through 9-8). The degree of the venting should be such
as to ensure that the passive digital motion during
surgery allows the tendon repaire site to glide freely
distal to or under the vented pulley. Whether the vented
part of the pulley needs to be excised or trimmed is still
questionable. Because the A2 pulley is thick and rigid,
if the release by an incision is judged to be insufficient,
it may be appropriate to remove a part of the incised
portion of the pulley, or a part of the pulley is trimmed
to form an oblique or oval opening.

95
Chapter 9:  Treatment of the Flexor Tendon Sheath and Pulleys
Figure 9-6  A case of venting of the entire A4 pulley when tendon passage under this pulley is difficult (A and B).
A
B
The function and treatment of the condensed sheath
parts, i.e., the pulleys, are complex and may even be
confounding. Most information on this subject has been
derived from investigations over the past two decades.36,37
Here, I summarize the current understanding of the
function and treatment of pulleys (1) Most pulleys (includ­
ing at least a part of the A2 pulley) should be preserved to
maintain normal digital function: most of the annular
pulleys, including at least part of the A2 pulley, should
be preserved during tendon repair. Individual minor
annular pulleys (A1, A3, PA, or A5) are not essential
Figure 9-7  A case of venting of the A2 pulley through the
midline. The distal 60% of the A2 pulley was vented.
Figure 9-8  Three methods of releasing pulleys: A, midline
incision; B, lateral incision; C, shortening (partial resection).
Pulley
Pulley
Shortened
part of
the pulley
A
B
C

96
Section 2:  Primary Flexor Tendon Surgery
obstacles to repaired tendon passage or are judged to
restrict tendon gliding during surgery.
CONSIDERATIONS
In the late 1980s, at the start of investigations of the
sheath, I was initially puzzled by a variety of suggestions
of sheath treatment by different surgeons. Over the past
two decades, I came to believe that the sheath and
pulleys can be treated by a more simple and straightfor­
ward principle. Although valid and theoretically sup­
ported, complicated repairs, or reconstructions, of the
synovial sheath are not a necessary part of the surgery.
Over the years, my practice has evolved from reconstruc­
tion of the lost synovial sheath, to leaving the injured
sheath unrepaired, and to intentional venting of the
critical part of a pulley that is too narrow. After I reviewed
my cases of pulley release and pondered the importance
of venting a part of the pulley to lessen resistance to
tendon motion, and compared it to a strong surgical
repair, another part of my past work, I came to realize
and became gradually convinced that a properly per­
formed pulley release is important and may even be a
vital step in improving the function of the tendons. This
procedure will probably be proved to be a key to com­
plete avoidance of repair rupture, eventually becoming
a critical step in reaching the elusive goal of predictable
outcome of flexor tendon repair.
It is very likely that outcomes of some of past cases,
treated by experienced and inexperienced surgeons
alike, have been affected by the way in which the pulleys
were treated, yielding a general impression of “unpre­
dictability” of flexor tendon repairs. When patients were
treated by inadvertent venting of the pulleys or the par­
tially lacerated pulleys were left unrepaired (which was
not unusual in cases treated by inexperienced physi­
cians), they may have achieved good results inexplica­
bly. Conversely, when surgeons strictly followed the
instruction to maintain the entire A2 pulley, repairing
both FDS and FDP tendons specifically, the cases had
unpredictably poor outcomes, even when the surgeons
were experienced. This remains a bold interpretation in
respect of the “unpredictability” of the outcome of past
cases, but I believe this is, at least, partly true.
My final comment is that pulley-release surgery
should be attempted only with precise mastery of pulley
anatomy and recognition of the borders of these pulleys
during dissection. Releasing of multiple pulleys (cruci­
ate and annular) or leaving a lengthy defect or opening
in the synovial sheath and pulleys is harmful and
impairs digital function. Such losses of a significant
length of the synovial sheath with multiple pulleys
should be reconstructed. My observation of operations
in a number of units in different countries has made
me aware that a significant number of surgeons have
not precisely mastered the anatomy of these pulleys.
I strongly advise that surgeons working in this field
functionally and, thus, may be incised to allow access to
the tendons. The A2 and A4 pulleys are the most impor­
tant functionally, but maintenance of the majority of the
other pulleys still is necessary for normal tendon func­
tion. (2) A part of the A2 pulley or the entire A4 pulley can
be incised without clinically significant loss of digital func­
tion: given that the other annular pulleys and adjacent
sheath are intact, the integrity of part of the A2 or the
entire A4 pulley is not as important as previously
believed;4 incision of part of the A2 or the entire A4
pulley does not result in remarkable functional distur­
bance. Therefore, part (but not all) of the A2 pulley or
part, or all, of the A4 pulley is expendable when the
other pulleys and most of the sheath are uninjured. (3)
Lengthy defects or incisions in the sheath should be avoided:
lengthy sheath defects lead to tendon bowstringing. The
allowable length of defects, or incisions, is less than
approximately 1.5 to 2 cm, depending on size of the
fingers. In exposing the lacerated tendon, we should
avoid incising a lengthy part of the sheath. Though not
commonly seen, the lengthy traumatic opening in the
sheath should be closed partially to reduce the length
of sheath opening, and the large defect should be recon­
structed. (4) Cruciate pulleys become important when
annular pulleys are lost: cruciate pulleys do not play a key
role in restraining tendon bowstringing in normal
fingers, but they do restrain the tendons when adjacent
annular pulleys are destroyed. If the annular pulleys are
intact, it is not necessary to repair the cruciate pulleys.
On the other hand, if the annular pulleys are not intact,
care should be taken to preserve the cruciate pulleys and
synovial sheath. (5) Two pulleys should be preserved in the
thumb: in the thumb, at least two pulleys should be pre­
served for better FPL function. Venting of either the A1
pulley or the oblique pulley in the presence of one of
the two pulleys and an intact A2 pulley is clinically
acceptable. (6) Two or three strong annular pulleys should
be preserved in secondary tendon surgery: during secondary
tendon grafting or tenolysis, at least two, or three, strong
annular pulleys at critical locations should be preserved
or reconstructed. Preservation of the A2 and A4 pulleys
is essential in secondary surgery.
My own practice has evolved. I no longer repair an
opening in the sheath except in some of very clean
wounds and at primary tendon repair. In delayed repair,
the sheath frequently has contracture, thickening, or is
embedded in immature adhesions. It was rarely possible
to close the sheath directly. In fact, I have not encoun­
tered a case in which the sheath could be approximated
easily without tension. I no longer continue my practice
of sheath plasty by interposing a graft and consider that
this procedure may not yield better results than the
much easier procedure of simple cutting, or venting, the
pulley. It is my current preference to simply incise a
part of the sheath-pulleys without performing any
reconstructive procedures, when the pulleys constitute

97
Chapter 9:  Treatment of the Flexor Tendon Sheath and Pulleys
References
1. Doyle JR: Anatomy of the finger flexor tendon sheath and
pulley system, J Hand Surg (Am) 13:473–484, 1988.
2. Manske PR, Lesker PA: Palmar aponeurosis pulley, J Hand
Surg (Am) 8:259–263, 1983.
3. Doyle JR, Blythe WF: Anatomy of the flexor tendon sheath
and pulleys of the thumb, J Hand Surg (Am) 2:149–151,
1977.
4. Lister G: Indications and techniques for repair of the flexor
tendon sheath, Hand Clin 1:85–95, 1985.
5. Strauch B, de Moura W, Ferder M, et al: The fate of tendon
healing after restoration of the integrity of the tendon sheath
with autogenous vein grafts, J Hand Surg (Am) 10:790–795,
1985.
6. Peterson WW, Manske PR, Bollinger BA, et al: Effect of pulley
excision on flexor tendon biomechanics, J Orthop Res 4:96–
101, 1986.
7. Peterson WW, Manske PR, Kain CC, et al: Effect of flexor
sheath integrity on tendon gliding: A biomechanical and his­
tologic study, J Orthop Res 4:458–465, 1986.
8. Saldana MJ, Ho PK, Lichtman DM, et al: Flexor tendon repair
and rehabilitation in zone II open sheath technique versus
closed sheath technique, J Hand Surg (Am) 12:1110–1114,
1987.
9. Manske PR: Flexor tendon healing, J Hand Surg (Br) 13:237–
245, 1988.
10. Tang JB, Ishii S, Usui M: Surgical management of the tendon
sheath at different repair stages. Biomechanical and morpho­
logical evaluations of direct sheath closure, partial sheath
excision, and interposing sheath grafting, Chin Med J (Engl)
103:295–303, 1990.
11. Gelberman RH, Woo SL, Amiel D, et al: Influences of flexor
sheath continuity and early motion on tendon healing in
dogs, J Hand Surg (Am) 15:69–77, 1990.
12. Savage R: The mechanical effect of partial resection of the
digital fibrous flexor sheath, J Hand Surg (Br) 15:435–442,
1990.
13. Tang JB, Ishii S, Usui M, et al: Flexor sheath closure during
delayed primary tendon repair, J Hand Surg (Am) 19:636–
640, 1994.
14. Tang JB: The double sheath system and tendon gliding in
zone 2C, J Hand Surg (Br) 20:281–285, 1995.
15. Tang JB, Shi D, Zhang QG: Biomechanical and histologic
evaluation of tendon sheath management, J Hand Surg (Am)
21:900–908, 1996.
16. Kwai Ben I, Elliot D: “Venting” or partial lateral release of the
A2 and A4 pulleys after repair of zone 2 flexor tendon inju­
ries, J Hand Surg (Br) 23:649–654, 1998.
17. Tang JB, Shi D, Shen SQ, et al: An investigation of morphol­
ogy and function of flexor tendons in zone IIc in the hand
and treatment of flexor tendons, Chin J Surg (in Chinese)
37:639, 1999.
18. Mitsionis G, Bastidas JA, Grewal R, et al: Feasibility of partial
A2 and A4 pulley excision: Effect on finger flexor tendon
biomechanics, J Hand Surg (Am) 24:310–314, 1999.
19. Tomaino M, Mitsionis G, Basitidas J, et al: The effect of partial
excision of the A2 and A4 pulleys on the biomechanics of
finger flexion, J Hand Surg (Br) 23:50–52, 1998.
20. Tang JB, Xie RG: Effect of A3 pulley and adjacent sheath
integrity on tendon excursion and bowstringing, J Hand Surg
(Am) 26:855–861, 2001.
21. Elliot D: Primary flexor tendon repair: Operative repair,
pulley management and rehabilitation, J Hand Surg (Br)
27:507–513, 2002.
22. Paillard PJ, Amadio PC, Zhao C, et al: Pulley plasty versus
resection of one slip of the flexor digitorum superficialis after
repair of both flexor tendons in zone II: A biomechanical
study, J Bone Joint Surg (Am) 84:2039–2045, 2002.
23. Tang JB, Wang YH, Gu YT, et al: Effect of pulley integrity
on excursion and work of flexion in healing flexor tendons,
J Hand Surg (Am) 26:347–353, 2001.
24. Xu Y, Tang JB: Effects of superficialis tendon repairs on lacer­
ated profundus tendons within or proximal to the A2 pulley:
An in vivo study in chickens, J Hand Surg (Am) 28:994–1001,
2003.
25. Tang JB, Xie RG, Cao Y, et al: A2 pulley incision or one slip
of the superficialis improves flexor tendon repairs, Clin Orthop
Relat Res 456:121–127, 2007.
26. Tanaka T, Amadio PC, Zhao C, et al: The effect of partial A2
pulley excision on gliding resistance and pulley strength in
vitro, J Hand Surg (Am) 29:877–883, 2004.
27. Tang JB: Indications, methods, postoperative motion and
outcome evaluation of primary flexor tendon repairs in Zone
2, J Hand Surg (Eur) 32:118–129, 2007.
28. Tang JB, Cao Y, Wu YF, et al: Effect of A2 pulley release on
repaired tendon gliding resistance and rupture in a chicken
model, J Hand Surg (Am) 34:1080–1087, 2009.
29. Cao Y, Tang JB: Strength of tendon repair decreases in the
presence of an intact A2 pulley: Biomechanical study in a
chicken model, J Hand Surg (Am) 34:1763–1770, 2009.
30. Tang JB, Zhang QG, Ishii S: Autogenous free sheath grafts in
reconstruction of injured digital flexor tendon sheath at the
delayed primary stage, J Hand Surg (Br) 18:31–32, 1993.
31. Bakhach J, Sentucq-Rigal J, Mouton P, et al: The Omega
“Omega” pulley plasty. A new technique to increase the diam­
eter of the annular flexor digital pulleys, Ann Chir Plast Esthet
50:705–714, 2005.
32. Bunata RE, Kosmopoulos V, Simmons S, et al: Primary
Tendon sheath enlargement and reconstruction in zone 2: An
in vitro biomechanical study on tendon gliding resistance,
J Hand Surg (Am) 34:1436–1443, 2009.
33. Bunata RE: Primary pulley enlargement in zone 2 by incision
and repair with an extensor retinaculum graft, J Hand Surg
(Am) 35:785–790, 2010.
34. Al-Qattan MM, Al-Turaiki TM: Flexor tendon repair in zone
2 using a six-strand “figure of eight” suture, J Hand Surg (Eur)
34:322–328, 2009.
35. Giesen T, Sirotakova M, Copsey AJ, et al: Flexor pollicis
longus primary repair: Further experience with the Tang tech­
nique and controlled active mobilisation, J Hand Surg (Eur)
34:758–761, 2009.
36. Tang JB: Clinical outcomes associated with flexor tendon
repair, Hand Clin 21:199-210, 2005.
37. Amadio P, An KN, Ejeskar A, et al: IFSSH Flexor Tendon Com­
mittee report, J Hand Surg (Br) 30:100–116, 2005.
review relevant anatomical descriptions in textbooks
or journals to obtain a clear and detailed knowledge of
the pulleys before performing these releases. Without
good mastery of the anatomy and clear recognition of
the major pulleys during surgery, (1) pulleys could be
insufficiently released and the procedures made ineffec­
tive, (2) the entire A2 pulley could be released, cutting
a series of annular pulleys, or (3) a lengthy segment of
injured sheath is left unattended, resulting in significant
loss of finger function.

98
CHAPTER
10 
VENTING OF THE MAJOR
PULLEYS
David Elliot, MA, FRCS, BM, BCh
Following identification of a synovial means of nutri­
tion and repair of injured flexor tendons, complete
repair of the flexor tendon sheath was advocated both
to reestablish the synovial environment of the tendon
and to diminish formation of adhesions, no longer
believed to be necessary for tendon healing and recog­
nized to be a hindrance to movement.1,4-8 The method­
ology of complete closure of the sheath following
primary tendon repair was elaborated by Lister.9 The
zeal to completely close the flexor sheath waned in the
1980s and 1990s from a lack of supportive evidence that
this is either necessary or beneficial.10-16
Various authors at this time pointed out again that
repaired, and thereby thickened, flexor tendons might
not move freely in the closed tendon sheath, because of
the increased diameter of the repaired tendon and/or
narrowing of the sheath by the process of closing it.1,16-22
The problems identified after complete closure of the
sheath were (1) complete immobility of the repair and
(2) (more likely) snagging of the repair on the edges of
adjacent pulleys during tendon movement. Such an
impediment to full mobility might be expected to cause
either a loss of range of motion of the digit or a rupture
of the repair during early postoperative mobilization,
depending on the vigor with which the hand was reha­
bilitated. It was suggested that it might be necessary to
partially release or “vent” the sheath laterally to achieve
a free-running repair.1,17,21 Strickland (1986) described
and illustrated the technique of lateral “venting” pulleys
but thought that this was only necessary when a particu­
lar bulky repair came to lie adjacent to a pulley, which
restricted its full excursion.21 In most instances, he con­
sidered that complete sheath closure without this
maneuver was possible. Schneider (1985) wrote that
“excising a portion of the sheath in badly damaged cases
may be required to allow free mobility of the tendon
juncture” and also admitted having been forced to
remove the A4 pulley on rare occasions with delayed
repairs.23 There has been no work done since Strickland
(1986) to identify any useful difference between split­
ting the pulleys laterally and in the midline.
OUTLINE
Review of the history of the management of the flexor
tendon sheath over the last half century is necessary
to understanding why venting the pulleys has met
with such resistance among hand surgeons. The
author’s clinical research illustrating why venting of
the A2 and A4 pulleys is necessary in clinical practice
is then described. This is followed by review of other
subsequent research supporting the practice of venting
these pulleys as a necessary surgical activity to ensure
safe rehabilitation of primary repairs of the digital
flexor tendons.
To repair flexor tendon injuries in zones 1 and 2, it is
inevitable that the tendon sheath be opened for access.
Over the past 40 years, treatment of the sheath on
completion of the tendon repair(s) appears to have
been determined partly on theoretical grounds and
partly by interpretation of the tendon healing research
at the time.
HISTORY
After primary repair, the subsequent discrepancy
between the external diameter of flexor tendons and the
internal diameter of the tendon sheath was first dis­
cussed by Mason in 1940.1 He pointed out the impor­
tance of excision of the sheath adjacent to the primary
repair and over a sufficient length to allow free gliding
of the repair. In 1958, Verdan2 again highlighted this
point, stating that “the sheath is excised over a distance
of about two to three centimeters, the amount of the
sheath to be resected was determined by estimating the
physiological gliding amplitude at this level.” Ketchum,3
in 1977, also mentioned the need to excise a portion of
the sheath. Although these authors were writing when
it was assumed that adhesion formation between the
tendons and the subcutaneous fat was necessary to
achieve repair of the sutured tendon, a secondary need
for adequate sheath excision to allow free movement of
the repair is clear.

99
Chapter 10:  Venting of the Major Pulleys
in flexion in zones 2A and 2B are those in which the
repairs of the flexor digitorum profundus (FDP) tendon
are likely to impinge on the proximal edge of the A4
pulley on finger extension. In fingers injured in exten­
sion, the tendon injury lies immediately beneath the
laceration of the sheath. These repairs are liable to
impinge on the distal edge of the A2 pulley on flexion
of the finger. After completion of each repair, the finger
was moved passively through a full range of motion and
the repair observed for catching on the proximal edge
of the A4 or distal edge of the A2 pulley. When catching
occurred, the appropriate pulley was vented along one
edge for as much of its length as was necessary to allow
a full and unimpeded range of motion of the repair. The
degree to which the A4 pulley had been vented was
expressed as a percentage of the total length of the
pulley. Venting of the distal edge of the A2 pulley was
measured and expressed in millimeters as expressing
this as a percentage of the whole of the A2 pulley would
have involved unnecessary opening of the base of the
finger and palm of the hand to measure the full length
of the A2 pulley. After venting of the pulleys, and achiev­
ing free movement through the full range of motion of
the finger, the sheath was laid over the flexor tendons,
hemostasis was achieved, and the skin of the finger was
closed. The fingers were then mobilized using the variant
of the controlled (early) active motion regimen we rou­
tinely use and have described previously.34
Of the 126 consecutive zone 2A and 2B injuries with
at least one tendon completely divided, 85 (67%) were
cut in flexion and 40 (32%) were cut in extension. The
position of the injury was not specified clearly in one
finger (1%). In eight cases (6%), the record of the find­
ings at surgery was unclear. A variable degree of venting
of the pulleys was necessary. In general, the length of
the pulleys is proportional to the length of the digit.35
The average length of the A2 pulley is between 18 and
20 mm.26,36 In this study, the A2 pulley was vented dis­
tally for between 4 and 10 mm, which represents 20%
to 50% of its average length. The degree of venting of
the A4 pulley ranged from 10% to 100% of its length
with a mean of 52%. In 14 cases, the A4 pulley had to
be completely divided. In all of these cases, the site of
division of the FDP tendon was in zone 2A close to, or
under, the A4 pulley. In all 14 cases, the surgeon par­
tially vented the A4 pulley and the assistant flexed the
distal interphalangeal (DIP) joint while holding the
proximal interphalangeal (PIP) joint straight to deliver
the distal stump from under the remainder of the A4
pulley and allow insertion of the core suture. In some
cases, complete division of the pulley was necessary to
insert the core suture into the distal end of the tendon.
In some, it was only necessary to partially vent the
pulley for access but the repaired tendon then impinged
on the distal remnant of the pulley on full finger exten­
sion and it was necessary to complete the division of
Throughout all of these reports, there was a palpable
reluctance to condone such venting of pulleys as, in
practice, this would usually entail partial division of the
A2 or the A4 pulleys, the complete integrity of which
was believed to be of great importance in maintaining
the mechanical efficiency of the flexor system.13,24-27
Toward the end of this period, and coinciding with the
waning of the enthusiasm for complete closure of the
flexor sheath, Savage (1990) questioned the absolute
need to preserve the A2 and A4 pulleys completely.20
Tomaino and his colleagues subsequently lent support
to Savage’s work.28,29
AUTHOR’S CLINICAL RESEARCH
There was also a degree of imprecision in these reports
as to which pulleys should be vented and by how much
and how often such releases were necessary. With this
background, we designed a prospective study to examine
those zone 2 injuries in which this problem arises most
commonly, namely those occurring between the proxi­
mal end of zone 1 and the distal edge of the A2 pulley,
designated zones 2A and 2B by Tang (1994)30 in his
proposed subdivision of the original zone 2 described
by Verdan and Michon (1961)31 and modified to its
present form by Kleinert and Weiland (1979).32 Over a
period of 29 months, 126 consecutive fingers with zone
2A and 2B flexor tendon injuries were repaired as part
of the routine emergency workload of our unit by senior
trainee plastic and orthopedic surgeons, who had been
briefed to vent the A2 or A4 pulley as necessary to
achieve sound tendon repairs and to allow the repaired
tendons to move passively through their full excursion
before closing the finger.33 Whenever possible, tendon
repair was carried out through the wound of the tendon
sheath with only sufficient further opening of the sheath
as necessary to allow tendon suture. In zones 2A and
2B, this usually requires release of part of the A3 pulley,
either distal, proximal, or both distal and proximal to
the initial wound. As the A3 pulley and the adjacent C
pulleys were not then considered essential to the pres­
ervation of full flexor mechanical function, particular
efforts to preserve this part of the tendon sheath were
not made and its fate was not recorded. When tendons
were injured close to, or under the A4 pulley, extension
of the tendon sheath wound to allow placement of the
intratendinous core suture often required some degree
of venting of the A4 pulley. A tendon injury adjacent to
the distal edge of the A2 pulley does not usually require
venting of the distal A2 pulley for repair as the tendons
can be drawn out distal to the pulley to undertake the
repair(s). In those fingers that were cut in partial flexion,
the tendon injury was identified more distally when the
finger was in the extended position necessary for surgi­
cal repair and was reached either by extending the
primary opening or, more commonly, through a sepa­
rate window of the sheath more distally. Fingers injured

100
Section 2:  Primary Flexor Tendon Surgery
FDS tendon to the middle phalanx, this helps explain
the need for different degrees of venting of this pulley
and how the FDP division could occasionally be distal
to the A4 pulley. Although the original definition of the
boundary between zone 1 and zone 2 was the distal
edge of the FDS insertion into the middle phalanx,31
there would be benefit in redefining it as the proximal
edge of the A4 pulley. This would both simplify discus­
sion of zone 1 and zone 2 injuries and bring this part
of the classification into line with the definitions of the
more proximal boundaries in the classification, which
are all defined in terms of the pulleys.
In summary, given the brief that two requisites—
good flexor repairs and a full range of motion passively
of all three finger joints after completion of the repairs—
were necessary, our senior fellows (all experienced in
this surgery and the surgeons most likely to carry out
this type of surgery in most specialist hand units) found
it necessary in clinical practice to vent the A2 or the A4
pulley in 81 fingers (64%), either to perform the flexor
tendon repair(s) or to allow the repairs to run freely
without snagging, or for both indications. This study of
the pulley to allow full mobility. In many instances,
repair of the FDP tendon at this level can be achieved
while leaving a small distal part of the pulley, with the
repair then moving through a full range of motion
without impinging on this remnant. It is questionable
whether pulley remnants of less than 10% to 20% of the
original length will continue to function adequately as
a pulley and do not snap during early mobilization. In
one case in this study, and in one subsequent case, the
FDP division was beyond the A4 pulley when the finger
was fully extended (Figure 10-1), requiring pulley
venting from distal to proximal to allow full passive
mobilization of the repair.
It was noted during the study that the length of the
flexor digitorum superficialis (FDP) insertion was vari­
able and that the relationship of the insertion of the FDS
tendon and the A4 pulley was inconstant. In examina­
tion of the latter relationship, we found that the FDS
insertion lay immediately beneath the A4 pulley in 22
cases (73%), whereas the FDS insertion was entirely
proximal to the A4 pulley in eight fingers (27%). Given
that Tang’s zone 2A is defined as the insertion of the
A
B
C
Figure 10-1  A, Division of both flexor tendons in zone
2B of the left ring and little fingers. B, The sheath has
been penetrated at the A3 pulley level. C, The FDP tendon
has been divided distal to the A4 pulley when the finger is
extended.

101
Chapter 10:  Venting of the Major Pulleys
skeleton could have given rise to changes in power of
flexion, not measured in our other studies.
DISTAL BOWSTRINGING
Visible distal bowstringing, which is a rare problem,
only occurs when there is a complete absence of the
sheath beyond the A2 pulley (Figure 10-2). This is
mostly an iatrogenic problem resulting from secondary
flexor tendon surgery that should not occur in primary
flexor tendon surgery if we retain all, or most, of the
sheath. In secondary flexor surgery, our entry into the
tendon sheath to visualize the tendons is usually
between the distal edge of the A2 pulley and the proxi­
mal edge of the A4 pulley, and this often leads to exci­
sion of much, or all, of the A3 and the adjoining C
pulleys. Later in the dissection, we find the A4 is often
not only small and very flimsy, but also tightly bound
to the underlying profundus tendon. During the subse­
quent tenolysis, it is too easy to snap the A4, leaving no
pulley system beyond the distal edge of the A2 pulley.
Visible distal bowstringing then occurs. We now rou­
tinely start all secondary surgery by keeping some of the
scarred sheath around the PIP intact as an A3 pulley, in
case we snap the A4 pulley later in the dissection. While
this paragraph digresses into secondary flexor tendon
surgery, it makes the point that we should aim to pre­
serve as much as possible of the sheath between the A2
and A4 pulleys when exploring flexor tendon injuries
distal to the A2 pulley when the finger has been cut in
flexion, whether in a primary or secondary surgical
setting. These observations are supported by the results
from a human cadaveric study by Tang and Xie.38
Although this study found the actual A3 pulley itself to
be of little importance compared with the surrounding
sheath and C pulleys, it did suggest that the sheath
routine flexor tendon repairs in zone 2 would suggest
that both the frequency and the degree of venting of
the A2 and A4 pulleys necessary in clinical practice are
greater than the earlier literature would suggest. The
inviolability of the A2 pulley was further undermined
by laboratory studies in chickens by Tang and his col­
leagues, which provided evidence of improved gliding
excursions and reduced resistance to motion of repaired
tendons after partial incision of the A2 pulley.37 Venting
of the A4 pulley, particularly in its entirety, is, arguably,
the more important debate, as the A2 pulley is so long
that it is unlikely that removal of any one-third of it will
cause bowstringing. Whether one vents the A4 pulley as
much as needed to allow full and free passive move­
ment of the repair or leaves the distal part of the A4
pulley intact and accepts a loss of full extension of the
DIP joint is a moot point, and one’s practice in this
respect will depend on how much credence one gives to
the research showing no absolute need for the A2 and
the A4 pulleys to always be completely intact. In this
study, we had hoped to confirm whether the practice of
dividing the A4 pulley entirely is harmful to long-term
flexor tendon function. This was thwarted by 5 of the
14 patients with complete A4 venting choosing to ter­
minate their follow-up before meaningful measure­
ments could be taken.
This study is incomplete in that it did not examine
the function of the fingers after full recovery to deter­
mine whether this policy of pulley venting leads to any
loss of range or power of flexion. From other studies
carried out in our unit during the same period and with
the same policy of pulley venting occurring as the
routine of the unit, it is unlikely that range of motion
was significantly affected. However, alteration of the
mechanical relationship between the tendons and the
Figure 10-2  A, Clinical picture of distal
bowstringing of the flexor tendons of the
finger following secondary flexor tendon
surgery in which the C1, A3, and C2 pulleys
were excised for access and the A4 pulley
subsequently snapped during tenolysis of
the distal FDP tendon. B, Diagrammatic
illustration of the removal of the C1, A3, C2,
and A4 pulleys.
A
A4
A3
A2
B

102
Section 2:  Primary Flexor Tendon Surgery
the relevant pulleys to accommodate the larger
tendon(s).40,41 Most clinicians who have tried to enlarge
pulleys at some period in their career are probably sus­
picious of the ability of the small sutures one has to use
in such repairs to withstand the forces involved in early
active motion, making it seem likely that it is the
remainder of the intact flexor sheath that is actually
functioning to restrain the tendon(s) against the skele­
ton of the finger. This being so, is the pulley reconstruc­
tion actually necessary?
THE SIGNIFICANCE OF PULLEY VENTING
Perhaps more realistic to clinical practice has been the
policy of Tang and his colleagues in China,42 which
takes the writings from this unit33,43 on this subject a
quantum step farther. This team not only describes
exactly what part of the tendon sheath should be, and
can be safely, vented for tendon repairs at different levels
of injury in the finger, including complete division of
the A4 pulley whenever necessary, but also raises the
need for such venting to that of a necessity if we are to
overcome the unpredictability of outcome of primary
flexor tendon repair in zones 1 and 2. In 2007, in a
review of primary flexor tendon surgery, Tang made the
statement, “It is, thus, obvious to me that even a multi­
strand tendon repair should be accompanied by proper
and sufficient release of the critical part or the entire
pulley in the vicinity of the repair, to eliminate the
danger of overloading the tendon as a result of tendon
gliding against the pulley rim or constriction by the nar­
rowest pulley parts.”42 In analyzing the critical points of
primary flexor tendon surgery, Tang considered appro­
priate release of the pulleys as probably most important,
followed by the use of strong repairs to increase the
margin of safety. He considered closure of the synovial
sheath of least importance and repair of the strong
annular pulleys over, or proximal to, edematous tendon
repairs to be positively harmful.
adjacent to the A3 pulley plays an important role in
preventing tendon bowstringing at the PIP joint.
So, the question remains unanswered as to whether
the clinical practice of venting pulleys has any deleteri­
ous effect on long-term flexor function. Conversely, the
long-term effect of retaining the A4 pulley in its entirety
in respect of loss of DIP extension is unknown but, pos­
sibly, more immediately obvious. The larger core and
circumferential sutures we are now using would seem
likely to lead to greater need for venting pulleys, both for
access and then to allow the repairs to move, as the new
sutures create added bulk at the repair site (Figure 10-3).
Discussion of the acceptability of venting pulleys has
continued into this century. The argument for preser­
vation of all pulleys has been supported indirectly by
two reports following the philosophy of Messina and
Messina39 of accepting the change in diameter of the
repaired tendon as inevitable and attempting to enlarge
Figure 10-3  The right little finger after primary repair of
both flexor tendons in zone 2B by a middle-grade trainee
with a two-strand Kessler core suture and a Silfverskiöld
circumferential suture. Full DIP joint extension could only be
achieved by venting two-thirds of the A4 pulley.
References
1. Mason ML: Primary and secondary tendon suture. A discus­
sion of significance in tendon surgery, Surg Gynecol Obstet
70:392–404, 1940.
2. Verdan CE: La reparation immediate des tendons fleuchis­
seurs dans le canal digital, Acta Orthop Belg 24 (suppl III):15–
23, 1958.
3. Ketchum LD: Primary tendon healing: A review, J Hand Surg
2:428–435, 1977.
4. Amadio PC, Hunter JM, Jaeger SH, et al: The effect of vincular
injury on the results of flexor tendon surgery in zone 2,
J Hand Surg (Am) 10:626–632, 1985.
5. Eiken O, Hagberg L, Lundborg G: Evolving biologic concepts
as applied to tendon surgery, Clin Plast Surg 8:1–12, 1981.
6. Lister GD, Kleinert HE, Kutz JE, et al: Primary flexor tendon
repair followed by immediate controlled mobilization,
J Hand Surg 2:441–451, 1977.
7. Lister GD: Indications and techniques for repair of the flexor
tendon sheath, Hand Clin 1:85–95, 1985.
8. Matthews P, Richards H: Factors in the adherence of flexor
tendon after repair, J Bone Joint Surg (Br) 58:230–236, 1976.
9. Lister GD: Incision and closure of the flexor sheath during
primary tendon repair, Hand 15:123–135, 1983.
10. Chow JA, Thomes LJ, Dovelle S, et al: A combined regimen
of controlled motion following flexor tendon repair in “no
man’s land,” Plast Reconstr Surg 79:447–455, 1987.
11. Gelberman RH, Woo SLY, Amiel D, et al: Influences of flexor
sheath continuity and early motion on tendon healing in
dogs, J Hand Surg (Am) 15:69–77, 1990.
12. Lister GD, Tonkin M: The results of primary flexor tendon
repair, J Hand Surg (Am) 11:767, 1986.
13. Peterson WW, Manske PR, Kain CC, et al: Effect of flexor
tendon sheath integrity on tendon gliding: A biomechanical
and histological study, J Orthop Res 4:458–465, 1986.
14. Peterson WW, Manske PR, Lesker PA: The effect of flexor
sheath integrity on nutrient uptake by primate flexor tendons,
J Hand Surg (Am) 11:413–416, 1986.

103
Chapter 10:  Venting of the Major Pulleys
30. Tang JB: Flexor tendon repair in zone 2C, J Hand Surg (Br)
19:72–75, 1994.
31. Verdan CE, Michon J: Le traitement des plaies des tendons
flechisseurs des doigts, Rev Chir Orthop et Repar l’App Mot
47:290–296, 1961.
32. Kleinert HE, Weiland AJ: Primary repair of flexor tendon
lacerations in zone II. In Tendon Surgery of the Hand, Verdan
C, editor, Edinburgh/London/New York, 1979, Churchill
Livingstone, pp 71–75.
33. Kwai-Ben I, Elliot D: “Venting” or partial lateral release of the
A2 and A4 pulleys after repair of zone 2 flexor tendon inju­
ries, J Hand Surg (Br) 23:649- 654, 1998.
34. Elliot D, Moiemen NS, Flemming AF, et al: The rupture
rate of acute flexor tendon repairs mobilised by the con­
trolled active motion regimen, J Hand Surg (Br) 19:607–612,
1994.
35. Idler RS: Anatomy and biomechanics of the digital flexor
tendons, Hand Clin 1:3–11, 1985.
36. Zancolli EA, Cozzi EP: Atlas of Surgical Anatomy of the Hand,
New York, 1992, Churchill Livingstone, pp 327–345.
37. Tang JB, Wang YH, Gu YT, et al: Effect of pulley integrity on
excursions and work of flexion in healing flexor tendons,
J Hand Surg (Am) 26:347–353, 2001.
38. Tang JB, Xie RG: Effect of A3 pulley and adjacent sheath
integrity on tendon excursion and bowstringing, J Hand Surg
(Am) 26:855–861, 2001.
39. Messina A, Messina JC: The direct midlateral approach with
lateral enlargement of the pulley system for repair of flexor
tendons in fingers, J Hand Surg (Br) 21:463–468, 1996.
40. Bunata RE: Primary pulley enlargement in zone 2 by incision
and repair with an extensor retinaculum graft, J Hand Surg
(Am) 35:785–790, 2010.
41. Dona E, Walsh WR: Flexor tendon pulley V-Y plasty: An alter­
native to pulley venting or resection, J Hand Surg (Br) 31:133–
137, 2006.
42. Tang JB: Indications, methods, postoperative motion and
outcome evaluation of primary flexor tendon repairs in Zone
2, J Hand Surg (Eur) 32:118–129, 2007.
43. Elliot D: Primary flexor tendon repair: Operative repair,
pulley management and rehabilitation, J Hand Surg (Br)
27:507–513, 2002.
15. Saldana MJ, Ho PK, Lichtman DM, et al: Flexor tendon repair
and rehabilitation in zone II: Open sheath technique versus
closed sheath technique, J Hand Surg (Am) 12:1110–1114,
1987.
16. Tang JB, Ishii S, Usui M, et al: Flexor sheath closure during
delayed primary tendon repair, J Hand Surg (Am) 19:636–
640, 1994.
17. Duran RJ, Houser RG: Controlled passive motion following
flexor tendon repair in zones 2 and 3. In AAOS Symposium
on Tendon Surgery in the Hand, St Louis, 1975, Mosby, pp
105–114.
18. Manske PR: Flexor tendon healing, J Hand Surg (Br) 13:237–
245, 1988.
19. Peterson WW, Manske PR, Dunlap J, et al: Effect of various
methods of restoring flexor sheath integrity on the formation
of adhesions after tendon injury, J Hand Surg (Am) 15:48–56,
1990.
20. Savage R: The mechanical effect of partial resection of the
digital fibrous flexor sheath, J Hand Surg (Br) 15:435–442,
1990.
21. Strickland JW: Flexor tendon injuries. Part 2: Flexor tendon
repair, Orthop Rev 15:701–721, 1986.
22. Tang JB, Shi D, Zhang QG: Biomechanical and histological
evaluation of tendon sheath management, J Hand Surg (Am)
21:900–908, 1996.
23. Schneider LH: Flexor Tendon Injuries, Boston, 1985, Little,
Brown, pp 47–75.
24. Barton NJ: Experimental study of optimal location of flexor
tendon pulleys, Plast Reconstr Surg 43:125–129, 1969.
25. Doyle JR: Palmar and digital flexor tendon pulleys, Clin
Orthop Relat Res 383:84–96, 2001.
26. Doyle JR , Blythe W: The finger flexor tendon sheath and
pulleys; anatomy and reconstruction. In AAOS Symposium on
Tendon Surgery in the Hand, St Louis, 1975, Mosby, pp 81–88.
27. Rispler D, Greenwald D, Shumway S, et al: Efficiency of the
flexor tendon pulley system in human cadaver hands, J Hand
Surg (Am) 21:444–450, 1996.
28. Mitsionis G, Fischer KJ, Bastidas JA, et al: Feasibility of partial
A2 and A4 pulley excision: Residual pulley strength, J Hand
Surg (Br) 25:90–94, 2000.
29. Tomaino M, Mitsionis G, Basitidas J, et al: The effect of partial
excision of the A2 and A4 pulleys on the biomechanics of
finger flexion, J Hand Surg (Br) 23:50–52, 1998.

104
CHAPTER
11 
THE OMEGA “Ω” FLEXOR
PULLEY PLASTY
Joseph Bakhach, MD
gliding have led several surgeons to abandon this
approach.3-8
The repair of injured digital flexor tendons, either
primarily or secondarily, is accompanied by an increase
in the diameter of the tendon where sutures are placed,
increasing resistance to movement.9 To avoid this risk,
several authors10-12 prefer to deal with the fibrous sheath
structure and propose a partial or a complete resection
of the A2 or A4 annular pulleys.
Enlarging the digital fibrous sheath by “venting” the
pulley is attractive theoretically.12 However, even if it
does improve the local mechanical conditions around
the tendon repair site, incision into the pulley structures
may decrease digital flexion to a certain degree. Ana­
tomic work has showed that the most remarkable loss
of function is caused by resection of the annular pulleys
A2 and A4.13 We thus began to imagine technical inno­
vations that would resolve this conflict more specifically
without affecting the integrity of the annular pulleys.
The Omega (“Ω”) pulley plasty we describe consists
of releasing one lateral pulley attachment from its cor­
responding lateral phalangeal bony surface. The most
relevant fact is that this technique preserves the ana­
tomical integrity of the pulley and its continuity with
the periosteum and the floor of the digital fibrous
sheath. If one attachment is released, the annular pulley
moves palmarly and rotates transversally, enhancing
its internal space. This procedure may provide better
gliding conditions for repaired flexor tendons. We
named this technique for pulley plasty Omega, or “Ω,”
reflecting the anatomical shape of the annular pulleys
cross-sectionally.
METHODS AND OUTCOMES
Anatomy of the Fibrous Digital
Sheath Tunnel
Though the anatomy of the digital fibrous sheath is
familiar, we review some points that are important for
explaining the Omega (“Ω”) pulley plasty. The pulleys
segmentally distributed along the synovial sheath differ
by their sites of insertion and their plasticity.14 The
OUTLINE
In this chapter, we present our methods for the Omega
plasty used to treat A4 and A2 digital flexor pulleys in
primary or delayed primary tendon repair. This proce­
dure expands the inner diameter of the annular pulleys
of the flexor sheath, but anatomically it does not
disturb the integrity of the pulleys. During surgery one
lateral attachment of the annular pulley is entirely
released from the corresponding anterior phalangeal
bony surface. Our clinical series includes 34 Omega
pulley plasties performed in 34 fingers of 27 patients.
In 15 patients, 19 pulley plasties were performed with
primary repair of flexor tendon rupture, while in the
remaining 12 patients, 15 Omega pulley plasties were
done concomitantly with delayed primary tendon
repair. Among the 34 fingers, 7 fingers subsequently
needed tenolysis 3 months after initial surgery. After
7-month mean follow-up, excellent results were seen
in 29 fingers (85%), and good in 5 fingers (15%)
according to Strickland criteria. The advantage of this
subperiosteal surgical release is that it increases pulley
diameter and inner volume, which accommodates
better tendon gliding.
The surgical management of traumatic flexor tendon
injuries, especially in zone 2 (sometimes called “no
man’s land”), has always been a controversial subject.
These injuries in zone 2 are accompanied by injuries to
the digital fibrous sheath. The later the injury is attended
to, the more fibrosis and collapse of the digital sheath
are likely. The methods for repairing the functional
flexor unit (i.e., the finger flexor tendons and their fibro-
osseous sheath) are still evolving, testifying to the ana­
tomical as well as the functional complexity of this
structure.
The conservative camp proposed the concomitant
repair of the digital fibrous tube with the primary suture
of the flexor tendon injuries to restore the sheath integ­
rity and avoid the formation of adhesions.1,2 However,
the failure of the fibrous sheath to heal and, more dra­
matically, the risk of creating a constriction to tendon

105
Chapter 11:  The Omega “Ω” Flexor Pulley Plasty
annular pulleys A1, A3, and A5 (also called articular
pulleys), are attached to the palmar joint plates of the
metacarpophalangeal (MP), the proximal interphalan­
geal (PIP), and the distal interphalangeal (DIP) joints,
respectively. The lengths of these pulleys change during
digital motion, with an approximate 50% retraction
after full digital flexion,13,15 whereas the A2 and A4
pulleys (bone pulleys) insert on the lateral phalangeal
crests in continuity with the lateral periosteum and with
the floor of the digital fibrous sheath tunnel. The A2
pulley is situated in the middle and proximal part of the
proximal phalanx, and the A4 pulley in the middle third
of the middle phalanx. The lengths of the A2 and A4
pulleys change somewhat (less than 25%) during digital
flexion.
All the relevant biomechanical studies to date agree,
giving functional priority in finger flexion to the A2 and
A4 pulleys.13,16 It is on these two pulleys that the pulley
plasty is performed during tendon repair in zone 2,17
more precisely in zones 2B and 2C.18
Operative Techniques
Pulley plasty during tendon surgery in zone 2 may be
necessary under two circumstances: (1) primary tendon
repair that generates an immediate impingement on or
impediment to the digital fibrous sheath tunnel and (2)
delayed management of injured tendons with a col­
lapsed and retracted digital fibrous sheath over the
injured area.
Omega Plasty of the A4 Pulley
For a description of the operative technique, we con­
sider a case of primary repair of an injured flexor digi­
torum profundus (FDP) tendon in zone 2B with the
finger in an intermediate flexed position. The wound is
cleaned. The digital fibrous sheath is exposed through
classic oblique incisions on both sides of the cutaneous
wound. The collateral neurovascular pedicles are dis­
sected and protected. The second cruciform (C2) pulley
is opened, and the stumps of the tendon are located.
If the finger is in an extended position, the distal
tendon stump is retracted and hidden completely under
the A4 pulley. It is necessary to flex the DIP joint to
expose the tendon and to place the two stumps in the
operative field (Figure 11-1).
The tendon suture is completed with the Kleinert
technique using Prolene 4-0 suture material with an
epitendinous continuous running suture using Prolene
6-0. The suture technique itself is not important, and
different methods can be used. After the reestablish­
ment of tendon continuity, finger extension brings the
sutured part of the tendon under the proximal edge of
the A4 pulley, where a conflict process obstructs the
tendon from sliding beneath the pulley. An A4 expan­
sion pulley plasty becomes necessary to free the tendon
motion.
Figure 11-1  A patient with FDP tendon injury in zone 2B
with the finger in an intermediate flexed position. The DIP
joint was passively flexed to bring the distal stump out of
the A4 pulley into the operative field.
The ulnar digital neurovascular bundle is retracted
and the entire ulnar phalangeal bone attachment of the
A4 pulley is exposed. The ulnar periosteum is sharply
incised along the body of the middle phalanx and freed
progressively from dorsal to palmar. The ulnar pulley
attachment is then reached and freed from the ulnar
phalangeal crest until it has been totally liberated
(Figure 11-2).
Despite the total release of the pulley insertion, the
integrity of the fibrous sheath is fully preserved, with
complete continuity between the pulley and the ante­
rior periosteum of the phalanx, which forms the floor
of the digital fibrous tunnel. This release produces a
lengthening of the pulley circumference and conse­
quently an enhancement of its internal diameter. This
induces the rotational movement of the tendon gliding
tunnel, which is the basic rationale of the Omega pulley
plasty.
Then we verify sliding of the tendon passively, par­
ticularly the suture area of the tendon through the proxi­
mal ring of the enlarged A4 pulley, by extending gently
the DIP joint (Figure 11-3). In case of any remaining
resistance, it is necessary to carry out a complementary
release of the periosteum flap until perfect concord
between the pulley volume and the tendon is achieved.
Finally, the expanded pulley is left free and no sutures
are placed to fix the pulleys to other structures. The
digital neurovascular bundle is placed back, and the C2
pulley is left to heal spontaneously.
In case of delayed primary management of an injured
tendon, the retracted and collapsed annular pulley is
expanded using the same plasty technique. Two tendi­
nous stumps are integrated within the expanded pulley.

106
Section 2:  Primary Flexor Tendon Surgery
Figure 11-2  A, B, The annular pulley is firmly fixed by two lateral attachments to the anterior crests of the phalanx.
C, D, Releasing one lateral attachment allows a rotational upward movement, increasing the internal diameter of the pulley.
B, D, Demonstrations in a cadaveric finger. Arrows indicate the side of release at the pulley attachment to the phalanx.
B
D
A
C
Figure 11-3  After the Omega plasty, passive extension of the DIP joint brings the suture area into the proximal edge of the
expanded A4 pulley, confirming free gliding of the tendon. A, Finger semiflexed. B, Finger extended.
A
B

107
Chapter 11:  The Omega “Ω” Flexor Pulley Plasty
which is obviously the origin of the resistance phenom­
enon during tendon sliding, has prompted a number of
authors to propose sheath excision in order to enlarge
the digital fibrous sheath.21,22 On one side, there is the
conservative stream, which preaches the sealing of the
digital fibrous sheath, opposed by those who advise its
resection. Between those two extreme attitudes, there is
a mixed position.23 It consists in freeing the pulleys as
necessary, thus making it possible to widen the digital
fibrous tube and to permit tendon sliding movement
without resecting the pulleys.
The work of Kwai Ben and Elliot12 is interesting. They
pointed out the frequent discrepancies between the
repaired flexor tendon volume and the diameter of its
digital fibrous tube. In a series of 126 fingers with
tendon injuries in zone 2A and 2B,12 71 fingers (56%)
required venting of the A4 pulley. In 10 fingers (8%) a
partial lateral section of the A2 pulley was performed,
extending 20% to 50% of its length.
This technique of venting the pulley, either partial or
total, practiced to permit the surgical tendon suture or
to facilitate normal sliding of the tendon, has been
accepted by the scientific community. Nevertheless, it
remains unsatisfactory from a biodynamic point of
view, because it eliminates a fundamental structure of
the tendon physiology.
There are numerous clinical situations in which a
conflict arises between the digital fibrous tunnel and its
contents. As far as the tendon rupture is concerned, the
position of the finger (extension or flexion) at the time
of the trauma should be determined. A rupture of the
FDP tendon in zone 2B or 2C with the finger extended
will generate a conflict between the tendon and the
distal ring of the A2 pulley. However, the rupture of the
FDP tendon in zone 2B with the finger in a flexed posi­
tion will bring the distal tendon stump under the A4
pulley and will make it difficult to reach for surgical
repair. The Omega plasty is done on the A4 pulley in
order to ensure the adaptation of the pulley volume to
that of the repaired tendon, avoiding any resistance and
offering normal tendon sliding (Figure 11-4).
In cases of neglected tendon injuries, the trauma to
the digital fibrous sheath and the retraction of the
tendon stump lead to fibrous sheath retraction and
pulley collapse along the gap between tendon ends
(Figure 11-5). This may require an Omega plasty of
the constricted pulley. It must be noted that about
half of our cases concern secondary repair of the rup­
tured tendon. This reveals, even today, ignorance of
tendon pathology on the part of non-specialized hand
surgeons.
After its release, the anatomical architecture of the
digital fibrous sheath (particularly the anatomy of the
A2 and A4 pulleys, with their bony attachments) allows
pulley enlargement and the creation of better condi­
tions for tendon sliding. The unilateral release of the
Omega Plasty of the A2 Pulley
The same operative technique is applied to the A2
pulley, with some adjustments due to the length of the
A2 pulley, which can be three to four times the length
of the A4 pulley. In our cases, when an A2 pulley plasty
was necessary, the conflict was located at the distal ring
of the A2 pulley. In all such cases, the Omega plasty
started on one side at the distal end of the pulley and
extended proximally. In our cases, the Omega plasties
in the A2 pulley were partial and never exceeded 50%
of the pulley length.
On each side of the expanded pulley, the synovial
sheaths injured during the initial trauma are opened
surgically to expose and repair the tendons, then left to
heal spontaneously. We prefer not to repair these syno­
vial flaps in order to avoid any constricting scar.
Postoperative Care
After surgery, we protected the pulley with an external
ring skin bandage on the middle phalanx for an A4
pulley, or on the proximal phalanx for an A2 pulley, and
adopted either the Kleinert or Duran protocol of post­
operative digital motion.
Outcomes
Between 2005 and 2007, we carried out 34 Omega
pulley plasties (34 fingers) in 27 patients; 20 men and
7 women, with an average age of 34 years.18 There were
11 index, 9 middle, 7 ring, and 7 little fingers. In 15
patients, 19 Omega pulley plasties were performed
immediately after injury together with primary flexor
tendon repairs. In the other 12 patients, 15 Omega
pulley plasties were carried out secondarily in the
delayed primary stage concomitantly with management
of the neglected injured flexor tendons. Among the total
34 plasties, 26 Omega pulley plasties involved the A4
pulleys and 8 involved the A2 pulleys. In 5 fingers, it
was necessary to make a proximal incision on the distal
palmar crease in order to find the retracted FDP tendon.
In 2 fingers the flexor digitorum superficialis (FDS)
tendon was also injured, and in one finger there was a
neck fracture of the proximal phalanx.
It was necessary to perform tenolysis in 4 cases (7
fingers) at the third month postoperatively because of
the persistence of a deficit in the active flexion of the
DIP joint despite the adapted physiotherapy.
The average period of follow-up was 7 months (range,
4 to 9 months) after tendon repairs and pulley plasty.
According to the Strickland classification, “excellent”
results of active motion were achieved in 29 fingers,
whereas the other 5 fingers achieved “good” results.19
DISCUSSION
The volume discrepancy between the repaired flexor
tendon in zone 2 and its digital fibrous sheath has long
been a concern among surgeons.20 This discrepancy,

108
Section 2:  Primary Flexor Tendon Surgery
decrease of 9% simulated active range of digital motion
after total section of the A2 pulley, and Savage28 assures
us that the A2 or A4 pulley can be removed, provided
the remaining digital fibrous sheath remains intact.
According to these previous reports, we believe the
Omega pulley plasty creates no risk of pulley rupture
and does not generate significant disturbance in tendon
biomechanics.
We maintain that preserving the anatomical integrity
of the pulley and one of its two attachments is sufficient
to maintain biomechanical properties. Intraoperative
observations of the expanded A2 and A4 pulleys show
that the newly healed bone insertion is sufficiently solid
to maintain the deep flexor tendon on its axis during
digital flexion.
The technique of pulley expansion that we describe
here completely preserves pulley integrity. It respects the
internal surface of the pulley and does not increase the
risk of tendon adhesions. After this procedure, it is not
pulley attachment does not impair its biomechanical
properties; we preserve the continuity of the pulley with
the phalangeal periosteum on one side and the second
pulley-to-bone attachment on the other. After surgery,
tissue healing will restore the continuity of the detached
pulley with the phalangeal crest. We have confirmed the
restoration of normal solidity of this new attachment in
the cases that required secondary tenolysis. Indeed, the
pulleys seemed to have regained their anatomical con­
tinuity and normal solidity, which was tested in the
presence of tendon motion during surgery of tenolysis.
Past investigations indicate that during digital flexion,
the pulleys are subject to stress from the flexor
tendons.13,24 Nevertheless, the threshold of tendon
rupture is far from being reached; that would require 7
times as much stress as occurs during digital grasp.25
Moreover, Mitsionis et al26 showed that the section of
half of the A2 or A4 pulley does not alter any bio­
mechanical properties, while Tang27 has recorded a
A
B
C
Figure 11-4  Rupture of the FDP tendon in zone 2B with
the left index finger in a flexed position. A, B, An Omega
plasty is performed on the total length of the medial A4
pulley attachment, allowing normal gliding of the repaired
tendon through the expanded pulley during surgery.
C, Complete recovery to normal flexion of the index finger
after surgery.

109
Chapter 11:  The Omega “Ω” Flexor Pulley Plasty
necessary to specifically modify protocols for postopera­
tive rehabilitation that we use.29,30 The only necessary
precaution is to protect the pulley plasty with an exter­
nal ring skin bandage.
Our experience indicates that the extent of pulley
release must be carefully considered. We accomplished
the release gradually with intraoperative assessment of
ample sliding of the tendon repair site inside the
expanded pulley. In our series, all Omega plasties on the
A2 pulley required a partial release not exceeding 50%
of the pulley’s attachment length, while the Omega
plasties of the A4 pulley required a complete release in
60% of our cases. In the remaining 40%, the release did
not extend more than the two thirds the length of the
A4 pulley.
Approximately 20% of operated fingers required
tenolysis by postoperative month 3 because of a persis­
tent loss of active flexion of the DIP joint. Presumably,
the loss of DIP joint motion was associated with the use
of Kleinert protocols. Rehabilitation began the day after
tendon release, and recovery of complete digital flexion
was obtained, on average, by the third month after the
tenolysis. These tendon adhesions varied depending on
the extent of the initial finger trauma and were gener­
ated by the healing processes around the repaired
tendon. In no cases could these adhesions be correlated
to the Omega pulley plasty itself.
SUMMARY
The Omega plasty of the fibro-osseous annular pulleys
(A2 or A4) is a simple and reliable procedure. The
release of the pulley from one side of its bony attach­
ment increases the spatial volume within the pulley and
accommodates greater motion of the repaired tendon.
This procedure may create favorable conditions for
recovery of tendon gliding and active digital flexion.
Tendon injuries are frequently accompanied by conflicts
and resistance to tendon gliding produced by the
annular pulleys. We are confident of the safety and
utility of this new technique, which may be considered
in primary, delayed, or secondary repairs of the flexor
tendons in zone 2.
Figure 11-5  Delayed primary repair of a FDP tendon
injury in a left ring finger. A, Collapse of the A4 pulley
(indicated by an asterisk) over a tendon gap. The end of the
proximal tendon is indicated by an arrow. B, Recovery of
the finger motion after pulley plasty performed on its one
attachment to the phalanx to increase pulley volume and
tendon gliding.
A
B
*
References
1. Lister GD: Incision and closure of the flexor tendon sheath
during primary tendon repair, Hand 15:123–135, 1983.
2. Lister GD, Tonkin M: The results of primary flexor tendon
repair with closure of the tendon sheath, J Hand Surg (Am)
11:767, 1986.
3. Amadio P, Hunter JM, Jaeger SH, et al: The effect of vincular
injury on the results of flexor tendon surgery in zone 2,
J Hand Surg (Am) 10:626–632, 1985.
4. Lister GD: Indications and techniques for repair of the flexor
tendon sheath, Hand Clin 1:85–95, 1983.
5. Eiken O, Hagberg L, Lundborg G: Evolving biologic concepts
as applied to tendon surgery, Clin Plast Surg 8:1–12, 1981.
6. Saldana MJ, Ho PK, Lichtman DM, et al: Flexor tendon repair
and rehabilitation in zone II: open sheath technique versus
closed sheath technique, J Hand Surg (Am) 12:1110–1114,
1987.
7. Tang JB, Ishii S, Usui M, et al: Flexor sheath closure during
delayed primary tendon repair, J Hand Surg (Am) 19:636–
640, 1994.
8. Tang JB, Shi D, Zhang QG: Biomechanical and histologic
evaluation of tendon sheath management, J Hand Surg (Am)
21:900–908, 1996.
9. Manske PR: Flexor tendon healing, J Hand Surg (Br) 13:237–
245, 1988.

110
Section 2:  Primary Flexor Tendon Surgery
20. Mason ML: Primary and secondary tendon suture. A discus­
sion of the significance of technique in tendon surgery, Surg
Gynecol Obstet 70:392–404, 1940.
21. Ketchum LD: Primary tendon healing: a review, J Hand Surg
2:428–435, 1977.
22. Verdan CE: La réparation immédiate des tendons fléchisseurs
dans le canal digital, Acta Orthop Belg Suppl III 15–23, 1958.
23. Strickland JW: Flexor tendon injuries. Part 2. Flexor tendon
repair, Orthop Rev 15:701–721, 1986.
24. Manske PR, Lesker PA: Strength of human pulley, Hand
9:147–152, 1977.
25. Schuind F, Garcia-Elias M, Cooney WP, et al: Flexor tendon
forces: in vivo measurements, J Hand Surg (Am) 17:291–298,
1992.
26. Mitsionis G, Fischer KJ, Bastidas JA, et al: Feasibility of partial
A2 and A4 pulley excision: residual pulley strength, J Hand
Surg (Br) 25:90–94, 2000.
27. Tang JB: The double sheath system and tendon gliding in
zone 2C, J Hand Surg (Br) 20:281–285, 1995.
28. Savage R: The mechanical effect of partial resection of the
digital fibreous flexor sheath, J Hand Surg (Br) 15:435–442,
1990.
29. Kleinert HE, Kutz JE, Cohen MJ: Primary repair of zone 2
flexor tendon lacerations. In AAOS Symposium on Tendons
Surgery in the Hand. St Louis, 1975, CV Mosby, p 91–104.
30. Duran RJ, Houser RG: Controlled passive motion following
flexor tendon repair in zones two and three. In AAOS Sympo­
sium on Tendons Surgery in the Hand. St Louis, 1975, CV
Mosby, p 105–114.
10. Peterson WW, Manske PR, Dunlap J, et al: Effect of various
methods of restoring sheath integrity on the formation of
adhesions after tendon injury, J Hand Surg (Am) 15:48–56,
1990.
11. Tomaino M, Mitsionis G, Basitidas J, et al: The effect of partial
excision of the A2 and A4 pulleys on the biomechanics of
finger flexion, J Hand Surg (Br) 23:50–52, 1998.
12. Kwai BI, Elliot D: “Venting” or partial lateral release of the A2
and A4 pulleys after repair of zone 2 flexor tendon injuries,
J Hand Surg (Br) 23:649–654, 1998.
13. Lin GT, Amadio PC, An KN, et al: Functionnal anatomy of
the human digital flexor pulley system, J Hand Surg (Am)
14:949–956, 1989.
14. Moutet F: Les poulies de l’appareil fléchisseur: anatomie,
pathologies, traitement, Annales de Chir Main 22:1–12, 2003.
15. Lin GT, Cooney WP, Amadio PC: Mechanical properties of
human pulleys, J Hand Surg (Br) 15:429–434, 1990.
16. Cleveland M: Restoration of the digital portion of a flexor
tendon and sheath in the hand, J Bone Joint Surg 15:762–765,
1933.
17. Verdan CE, Michon J: Le traitement des plaies des tendons
fléchisseurs des doigts, Rev Chir Orthop et Répar 47:290–296,
1961.
18. Tang JB: Flexor tendon repair in zone 2C, J Hand Surg (Br)
19:72–75, 1994.
19. Bakhach J, Mouton P, Panconi B, et al: The Omega pulley
plasty. A new technique to increase the diameter of the
annular flexor digital pulleys, Ann Chir Plast 50:705–714,
2005.

111
CHAPTER
12 
TENDON SHEATH AND PULLEY
ENLARGEMENT
Robert E. Bunata, MD
a slight enlargement using a fascial graft as Lister recom­
mended for a deficient sheath. This seemed to solve the
problem of providing a nonrestrictive gliding environ­
ment for the repair while adequately restoring impor­
tant sheath support. The result of that surgery was
surprisingly good. Since then this technique has been
applied to either the A2 or A4 pulleys in a total of 12
fingers in 9 patients, which represent the more difficult
patients treated over a 20-year period.7
Since those developments early in the history of
primary repairs of flexor tendons, attention and research
have made tendon repairs stronger to prevent rupture if
subjected to increased resistance. Stronger repairs are
often more bulky and can make gliding even more dif­
ficult and catching more likely. Even the strongest repair
might rupture if an exposed edge of pulley that com­
pletely blocks motion is encountered.8 Venting has
become an accepted method of sheath management,
being a way to preserve enough of the essential pulleys
while improving tendon gliding. Venting allows free
gliding to occur only within the vented area, and the
repair must often reenter a tight, restrictive sheath,
exposing the repair to catching on an edge of sheath or
to traversing an area of resisted gliding.
Other methods that have been suggested to solve the
same problem include removal of one slip of flexor
digitorum superficialis (FDS), pulley enlargement by
V-Y plasty, and pulley release from the underlying
phalanx.7,9-18 Tang and colleagues have shown complete
pulley incision with or without graft repair in chickens
reduces work of flexion even after the effects of time and
healing are included.12,19,20 Tang8,11 and Elliot10 have even
recommended completely cutting the A4 pulley as stan­
dard clinical practice despite the continuing belief that
at least some of the A2 and A4 pulleys are essential to
preventing bowstringing and preserving the efficiency of
finger flexion.
Because of the encouraging results in the clinical
patients, during the past 5 years laboratory investiga­
tions have been conducted to explore how this tech­
nique affects gliding within the enlarged sheath,
triggering, and bowstringing. These are summarized
below along with the surgical technique and the clinical
outcomes.
OUTLINE
This chapter presents the results of clinical experience
and laboratory studies related to the idea of enlarging
and then repairing a major pulley and closing the
sheath at the time of primary flexor tendon repairs.
This procedure is intended to give room for the more
bulky tendon repairs to slide while providing an intact
sheath and pulley system that guides the repair and
prevents bowstringing. The clinical data on a series of
patients and a description of the surgical technique are
presented, and the laboratory studies provide biome­
chanical findings regarding tendon gliding, triggering,
and bowstringing after this procedure. This chapter
deals with an alternate solution to the problem of
getting a bulky flexor tendon repair to glide freely
without triggering while maintaining the adequate
sheath support that is required for efficient finger
flexion. This solution is at odds with the axiom of
keeping as much as possible of the major A2 and A4
pulleys intact, and instead cuts an obstructing pulley,
subsequently repairing it with a slight enlargement.
The history of dealing with this problem started with
the earliest attempts at primary flexor tendon repair and
continues to the present time. When Kleinert and col­
leagues published their successful primary tendon
repairs in zone 2 combined with early motion in 1973,
he initially resected a window of tendon sheath.1 Ten
years later, Lister and coworkers advocated closure of the
tendon sheath following a limited, pulley preserving
tendon exposure.2 In 1983, they advocated complete
closure of the sheath so that catching of the repair on
an edge of sheath would be avoided, and in 1985 Lister
described replacing a deficient sheath with a fascial graft
to accomplish closure.3,4 However, others realized that
tight sheath closure might restrict the free gliding of the
sutured tendons.5,6
This author first used the procedure of pulley enlarge­
ment in 1985 for a patient whose bulky tendon repair
would not glide into or through the A4 pulley. Contrary
to the dictum of A2 and A4 pulley preservation, the
entire A4 pulley was cut. Because of concern that bow­
stringing could result, the A4 pulley was repaired with

112
Section 2:  Primary Flexor Tendon Surgery
retinaculum. A transverse ellipse of extensor retinacu­
lum 5 mm wide × 30 mm long is removed. Any septal
remnants are excised and any defects repaired to present
a smooth, synovial lined graft. The 5-mm gap in the
donor site retinaculum is closed side-to-side with
absorbable, interrupted sutures, and the wrist skin inci­
sion with subcuticular absorbable suture. The elliptical
graft is trimmed to fit to the retinacular sheath and
pulley defect of the finger and sutured in place, synovial
side toward the tendon repairs, with a running horizon­
tal mattress, alternately locked, 6-0 nylon suture under
enough tension to support but not restrict the gliding
of the tendons. This usually requires a 2 mm enlarge­
ment and the graft requires about 20 suture passes per
side for closure. Additional injuries or lacerations in the
tendon sheath are closed with everting, interrupted 6-0
sutures.
Clinical Outcomes
Seven of the nine patient were followed to an adequate
follow-up ranging from 3 months to 11 years.7 All seven
patients (nine digits) were treated as primary flexor
tendon repairs in zone 2 preferably with the surgery
delayed 2 or 3 days to be confident that the wound was
not contaminated. All were managed postoperatively
with Kleinert’s original rehabilitation protocol, which
was begun immediately following surgery in the recov­
ery room. The final total active interphalangeal joint
motion of the nine digits averaged 127.5° of a possible
maximum of 175° (Table 12-1). The final range of
motion ranged from 65° to 175°. The scores according
to the Strickland-Glogovac system were three excellent,
two good, two fair, and two poor.21 There were no
tendon ruptures despite the use of a two-strand core
repair. Two fingers in one patient required a tenolysis,
and one finger in another patient had a secondary skin
scar lengthening. These secondary operations improved
finger motion. Only three of the nine digits attained full
PIP joint extension, with the average lack of extension
(flexion contracture) for the nine fingers being 21°.
While the Kleinert rehabilitation protocol has been
associated with developing flexion contractures, they
may be the result of bowstringing if the grafts stretched
with time and/or use.7 One finger, the right ring finger
of patient 3, had visible and palpable bowstringing
when seen at follow-up post tenolysis. Another finger,
the right little finger of patient 4, had clinical evidence
of bowstringing at follow-up.
The two patients with bowstringing merit comment.
The sheath repair of right little finger of patient 4 may
have been too loose because even a limited enlargement
of the small fifth digit sheath can be disproportionately
large. The right ring finger of patient 3 had no evidence
of bowstringing at 6 months, immediately before a
tenolysis to improve flexion was performed. When seen
18 years later, this finger had midline skin callous
SURGICAL TECHNIQUE
Operative Techniques
The flexor tendon sheath is exposed and examined with
the finger in full extension. Tendon and sheath injuries
are evaluated and the anticipated excursion of the
repaired tendon is identified. If the flexor digitorum
profundus (FDP) lies within the A4 pulley or if both
tendons might have to pass under the A2 pulley, sheath
and pulley enlargement might be needed, and the
sheath, including any part of a pulley, is opened far
enough to provide adequate exposure for easy tendon
repair. The sheath injury is extended distally until, with
the help of distal interphalangeal joint flexion, a core
suture can be placed in the FDP stump. The sheath/
pulley incision is placed lateral to the volar midline,
leaving enough sheath tissue to secure a suture and
adjusting the incision to fit the conditions of the original
injury. The distal FDS is always longer than the FDP and
readily visible with this exposure. The proximal tendons
are retrieved. If needed, the proximal sheath/pulley is
incised far enough to allow room so that an easy tendon
repair can be performed. Both tendons are repaired.
In the series, all tendons or tendon slips were repaired
with a two-strand modified Kessler repair using 3-0
suture. The suture was performed starting in the distal
tendon segment with a 1-cm longitudinal insertion and
a locking loop followed by the transverse pass and a
grasping loop leading back to the tendon end. The iden­
tical pattern was used in the proximal tendon segment.
This allowed easy tensioning until the ends abutted
without bunching and there was no gapping when
placed under manual tension. The triple-throw sur­
geon’s knot was buried inside the repair. All repairs were
reinforced and smoothed with a circumferential
running, alternately locked, 6-0 nylon suture, making
10 to 12 passes around each tendon and 6 to 8 passes
around each tendon slip. The 6-0 suture was tied with
one triple-throw square knot on the external lateral
tendon surface. A stronger repair can be substituted if
preferred.
Once the tendons are sutured, the excursion of the
repairs is checked by passively extending the finger and
by pulling on the tendons through a palm incision to
flex the finger. If any intact sheath or pulley tissue
restricts the full excursion of the repair pulley, enlarge­
ment may be indicated and the sheath/pulley incisions
are extended even if this means completely incising an
entire major pulley. If an entire A2 or A4 pulley is cut,
the entire sheath is repaired and closed with an extensor
retinaculum graft in an attempt to reestablish the incised
major pulley in order to limit bowstringing and guide
the tendons into the sheath without snagging.
The graft is obtained through a transverse skin inci­
sion on the dorsum of the wrist extending from the
second to the sixth compartments of the distal extensor

113
Chapter 12:  Tendon Sheath and Pulley Enlargement
Study of the effect of venting and pulley enlargement
on the incidence of triggering in the force recordings
(see Figure 12-1B) revealed that after the bulk of the
tendon was increased by tendon repair, triggering
occurred in some fingers. Venting alone had a variable
effect on the incidence of this triggering, but closing the
sheath with enlargement provided smoother gliding of
the repair and reduced the incidence of triggering.3,29,30
Regarding bowstringing, in a preliminary, unpub­
lished study of nine cadaver fingers, total range of
motion (TROM) in the uninjured state was compared
to the motion after cutting the A4 pulley plus additional
sheath for the distance equal to the FDP excursion, and
then to the motion after that sheath was repaired with
a 2-mm-wide fascial graft. Cutting the sheath reduced
the finger TROM to 93.8% of normal. Repairing the
sheath and pulleys enlarged by 2 mm brought the loss
of TROM to 99.3% of the uninjured state. This suggests
that a 2-mm enlargement may preserve acceptable finger
flexion efficiency. We have not tested how well the
pulley repair holds up under stress and with time. With
more tension on the tendons or with time, the pulley
repair may stretch. This technique of the pulley repair
requires further study to evaluate the need or benefit of
strengthening or reinforcement.
DISCUSSION
Considering the three goals of sheath and pulley man­
agement during primary zone 2 flexor tendon surgery
of providing a good gliding environment, avoiding trig­
gering, and minimizing bowstringing, this experience
with sheath enlargement and repair may offer insight
into future research and clinical practice, especially with
regards to the benefits of a closed sheath. The surgeon
has the option and obligation to reconsider decisions
formation directly over underlying flexor tendons which
were distinctly prominent during gripping. The PIP joint
had complete extension and 95° flexion; the DIP joint
motion was 30/65°. Possible explanations for this may
be: (1) there was bowstringing present at 6 months that
was not detected, (2) the sheath function was damaged
during the tenolysis, or (3) the graft stretched from
heavy use over the following 18 years.
BIOMECHANICAL STUDIES
Uchiyama and colleagues’ method of testing resistance
of an isolated segment of the tendon/tendon sheath
provides the opportunity of observing and testing the
effects of sheath enlargement and repair on gliding resis­
tance and triggering.22 Using a tensioning force (F1)
through a load cell attached to the distal FDP and an
activating force (F2) through a proximal load cell, force
recordings as seen in Figure 12-1A, are obtained. The
difference in force between the load cells is the gliding
resistance (the friction between the tendon and the
sheath).
Gliding resistance measurements in our laboratory
for the normal, uninjured A1 through A3 segment has
averaged about 0.4 N (see red line in Figure 12-1A).
After the FDP is cut and repaired with a two-strand 3-0
core suture and running, locked 6-0 epitenon suture,
gliding resistance increases to 1.25 to 1.5 N, or by 200%
to 250% (see blue line in Figure 12-1A). These values
are similar to what others have found for various tendon
suture techniques.18,23-28 Experiments done in our labo­
ratory revealed that either venting (50% or 66%) or a
2-mm sheath enlargement and repair reduces the resis­
tance to approximately 1.0 N, or by 22% to 31% from
the tendon repair resistance level (see green line in
Figure 12-1A).
Table 12-1  Patient Information About Injuries, Operations, and Follow-Up
Patients
Age(y)/
Gender
Digit(s)
Injured
Tendon(s)
Repaired
Pulleys
Incised
Follow-Up
PIP Joint
Motion
DIP Joint
Motion
TAM
Grade
1
54/M
L middle
FDP/FDS
Mid-A2, A3, A4
11 yr
30/105
0/85
160
Excellent
2
18/M
R little
FDP/FDS
Mid-A2, A3, A4
2 yr
45/90
0/90
135
Good
3
21/M
R ring
FDP
A3, A4
6 mo
0/90
20/34
105
Fair*
R little
FDP
A3, A4
30/90
25/40
75
Poor
4
17/M
R ring
FDP/FDS
Mid-A2, A3, A4
5.5 yr
15/100
15/50
120
Fair
R little
FDP/FDS
Mid-A2, A3, A4
50/90
20/45
65
Poor**
5
20/M
R middle
FDP/FDS
A2, A3
3 mo
0/100
0/65
165
Excellent
6
45/F
L ring
FDP/FDS
A2, A3
1.5 yr
20/95
0/70
145
Good
7
15/M
R index
FDP/FDS
Mid-A1, A2, A3
3 yr
0/115
0/60
175
Excellent
M, Male; F, Female; R, Right; L, Left. Graded by Strickland-Glogovac method.21
*Finger without clinical observable tendon bowstringing 6 months after tendon repair before tenolysis, but had clinically observable
bowstringing when examined 18 years after tenolysis.
**Finger with clinically observable bowstringing after primary surgery.

114
Section 2:  Primary Flexor Tendon Surgery
throughout an operation. During primary repair, pulley
and sheath enlargement may be a useful choice to
provide repaired tendon with adequate tendon gliding
amplitude.
Use of the technique of sheath enlargement should
be carefully considered. More basic and clinical investi­
gation is needed before it can be considered an
References
1. Kleinert HE, Kutz JE, Atasoy E, et al: Primary repair
of flexor tendons, Orthop Clin North Am 4:865–876,
1973.
2. Lister GD, Kleinert HE, Kutz JE, et al: Primary flexor tendon
repair followed by immediate controlled mobilization,
J Hand Surg (Am) 2:441–451, 1977.
3. Lister GD: Incision and closure of the flexor sheath during
primary tendon repair, Hand 15:123–135, 1983.
4. Lister GD: Indications and techniques for repair of the flexor
tendon sheath, Hand Clin 1:85–95, 1985.
5. Manske PR: Flexor tendon healing, J Hand Surg (Br) 13:237–
245, 1988.
Figure 12-1  Force recordings generated using Uchiyama et al testing technique. F1 is tensioning force; F2 is activating
force. A, Resistance recordings during tendon gliding in a simulated digital flexion cycle. Red, force recorded without tendon
injuries; blue, force tracing after the FDP tendon has been cut and repaired; green, force tracing after the sheath has been
enlarged. B, An example of the force recordings when triggering occurs. Orange, gliding resistance (F2). An increase (A) in
gliding resistance followed by a sudden drop (B), associated with a disturbance in F1 (purple, C), called an echo, indicate
triggering.
2
3
4
5
6
7
8
Force (N)
2
3
4
5
6
7
8
Force (N)
F1
Uninjured
F2 sheath
enlarged
F2 tendon repair
F1
F2
A
B
A
B
C
25
30
35
40
45
50
22
27
32
37
Time(s)
Time(s)
established procedure. The procedure carries the risks of
increasing the sheath injury, cutting a major pulley,
obtaining a distant graft, and inserting a graft of uncer­
tain strength to repair the cut pulley, but for those
patients in which a strong repair plus venting do not
permit adequate tendon excursion, complete pulley
enlargement may become an option.

115
Chapter 12:  Tendon Sheath and Pulley Enlargement
19. Tang JB, Wang YH, Gu YT, et al: Effect of pulley integrity on
excursions and work of flexion in healing flexor tendons,
J Hand Surg (Am) 26:347–353, 2001.
20. Tang JB, Cao Y, Wu YF, et al: Effect of A2 pulley release on
repaired tendon gliding resistance and rupture in a chicken
model, J Hand Surg (Am) 34:1080–1087, 2009.
21. Strickland JW Glogovac SV: Digital function following flexor
tendon repair in zone II: A comparison of immobilization
and controlled passive motion techniques, J Hand Surg (Am)
5:537–543, 1980.
22. Uchiyama S, Coert JH, Berglund L, et al: Method for the
measurement of friction between tendon and pulley, J Orthop
Res 13:83–89, 1995.
23. Tanaka T, Amadio PC, Zhao C, et al: Gliding resistance versus
work of flexion–two methods to assess flexor tendon repair,
J Orthop Res 21:813–818, 2003.
24. Tanaka T, Amadio PC, Zhao C, et al: Gliding characteristics
and gap formation for locking and grasping tendon repairs:
A biomechanical study in a human cadaver model, J Hand
Surg (Am) 29:6–14, 2004.
25. Zhao C, Amadio PC, Zobitz ME, et al: Gliding resistance after
repair of partially lacerated human flexor digitorum profun­
dus tendon in vitro, Clin Biomech 16:696–701, 2001.
26. Zhao C, Amadio PC, Tanaka T, et al: Effect of gap size on
gliding resistance after flexor tendon repair, J Bone Joint Surg
(Am) 86:2482–2488, 2004.
27. Paillard PJ, Amadio PC, Zhao C, et al: Gliding resistance after
FDP and FDS tendon repair in zone II: an in vitro study, Acta
OrthopScand 73:465–470, 2002.
28. Coert JH, Uchiyama S, Amadio PC, et al: Flexor tendon-
pulley interaction after tendon repair. A biomechanical study,
J Hand Surg (Br) 20:573–577, 1995.
29. Amadio P, An KN, Ejeskar A, et al: IFSSH Flexor Tendon Com­
mittee report, J Hand Surg (Br) 30:100–116, 2005.
30. Bunata RE, Simmons S, Roso M, et al: Gliding resistance and
triggering after venting or A2 pulley enlargement: A study
of intact and repaired flexor tendons in a cadaveric model,
J Hand Surg (Am) 36:1316–1322, 2011.
6. Strickland JW: Flexor tendon surgery. Part 1: Primary flexor
tendon repair, J Hand Surg (Br) 14:261–272, 1989.
7. Bunata RE: Primary pulley enlargement in zone 2 by incision
and repair with an extensor retinaculum graft, J Hand Surg
(Am) 35:785–790, 2010.
8. Tang JB: Indications, methods, postoperative motion and
outcome evaluation of primary flexor tendon repairs in Zone
2, J Hand Surg (Br) 32:118–129, 2007.
9. Elliot D, Moiemen NS, Flemming AF, et al: The rupture rate
of acute flexor tendon repairs mobilized by the controlled
active motion regimen, J Hand Surg (Br) 19:607–612, 1994.
10. Elliot D: Primary flexor tendon repair: operative repair, pulley
management and rehabilitation, J Hand Surg (Br) 27:507–
513, 2002.
11. Tang JB: Clinical outcomes associated with flexor tendon
repair, Hand Clin 21:199–210, 2005.
12. Tang JB, Xie RG, Cao Y, et al: A2 pulley incision or one slip
of the superficialis improves flexor tendon repairs, Clin Orthop
Relat Res 456:121–127, 2007.
13. Messina A, Messina JC: The direct midlateral approach with
lateral enlargement of the pulley system for repair of flexor
tendons in fingers, J Hand Surg (Br) 21:463–468, 1996.
14. Paillard PJ, Amadio PC, Zhao C, et al: Pulley plasty versus
resection of one slip of the flexor digitorum superficialis after
repair of both flexor tendons in zone II: A biomechanical
study, J Bone Joint Surg (Am) 84:2039–2045, 2002.
15. Zhao C, Amadio PC, Zobitz ME, et al: Resection of the flexor
digitorum superficialis reduces gliding resistance after zone II
flexor digitorum profundus repair in vitro, J Hand Surg (Am)
27:316–321, 2002.
16. Dona E, Walsh WR: Flexor tendon pulley V-Y plasty: An
alternative to pulley venting or resection, J Hand Surg (Br)
31:133–137, 2006.
17. Bunata RE, Kosmopoulos V, Simmons S, et al: Primary tendon
sheath enlargement and reconstruction in zone 2: An in vitro
biomechanical study on tendon gliding resistance, J Hand Surg
(Am) 34:1436–1443, 2009.
18. Tanaka T, Amadio PC, Zhao C, et al: The effect of partial A2
pulley excision on gliding resistance and pulley strength in
vitro, J Hand Surg (Am) 29:877–883, 2004.

116
CHAPTER
13 
CLINICAL PRIMARY FLEXOR
TENDON REPAIR AND
REHABILITATION
Esther Vögelin, MD, PhD, Ghislaine
Traber-Hoffmann, MD, and
Véronique van der Zypen, BSC PT
A
The Bern Experience
risks of rupturing the repairs. Not only repair techniques
but also postoperative mobilization require a balance
between these two extremes.
The repair that Lim and Tsai advocated5,6 was found
to have the mechanical strength required for unrestricted
active finger flexion in vitro.5,7 We used the Lim/Tsai
repair with an early active tendon motion regimen and/
or place-and-hold exercise between 2003 and 2005. We
noted that despite the need to mobilize repaired flexor
tendons early, an active motion protocol may not be
possible to apply in a substantial number of patients
due to concomitant injuries, the quality of the surgical
repair, or patient factors such as swelling, pain, or lack
of compliance. We therefore started a staged rehabilita­
tion program using the “stop and go” principal in the
style of a traffic signal: early active controlled flexion
(green), place-and-hold (yellow), or passive flexion exer­
cises (red) depending on different factors of the patient
such as the severity of injury, the ease of repair or the
postoperative compliance.
Since August 2006, we have combined the six-strand
Lim/Tsai suture repair with “stop and go” method of
postsurgical rehabilitation in all flexor tendon repairs,
and these methods remain our current practice of treat­
ment of tendon injuries in zone 2.
METHODS AND OUTCOMES
Patients
We reviewed and compared results of three cohorts of
patients with flexor tendons repairs in zone 2 in the
Hand Surgery Department of the University Hospital
of Bern. From 2003 to 2007, a total of 76 patients
OUTLINE
In this chapter we present our experience with treat­
ment of zone 2 flexor tendon repair using a six-strand
repair technique combined with postoperative place-
and-hold exercise. The six-strand Lim/Tsai repair
technique combined with place-and-hold exercises
demonstrated better digital function compared to a
two-strand repair without place-and-hold exercises.
Range of motion in the Lim/Tsai repair group appeared
to be increased without a higher rate of ruptures but
with a shorter rehabilitation period. The fact that the
two groups differed in both suture techniques and
rehabilitation programs made it impossible to know
whether the better results in the group of Lim/Tsai
were due to the six-strand repair or the place-and-hold
exercises or both. Despite the obvious benefit of early
active mobilization, an active motion protocol may
not always be possible to apply in a substantial number
of patients due to concomitant injuries, the quality of
the surgical repair or patient factors (swelling, pain,
limited compliance). Since August 2006 a staged reha­
bilitation program (“stop and go”) was introduced
within our unit using early active controlled flexion
(green), place-and-hold (yellow), or passive flexion
exercises (red) introduced by Kleinert-Duran. Our
experience using the six-strand suture repair technique
and “stop and go” is outlined.
Functional results after flexor tendon repair in zone 2
have markedly improved over the past three decades.1-4
However, a big dilemma of flexor tendon repair in zone
2 remains the challenge between scar formation and

117
Chapter 13A:  The Bern Experience
exact TAM values up to 12 weeks. After 12 weeks, the
patient files often contained only qualitative statements
without mentioning the degrees of TAM or only giving
the remaining extension deficits.
In case of an extension lag resisting physical therapy,
treatment with an extension splint was started only 5
weeks after surgery. The need for secondary surgery,
occurrence of tendon rupture, dehiscence, contracture
of joints, and the use of extension splints were com­
pared in both groups. A tendon rupture was defined as
a complete gap separation without any detectable
tendon function clinically. When the tendon remained
in continuity due to scar formation and still showed an
impaired function, we defined it as a dehiscence. Their
diagnosis and difference could be confirmed during
secondary surgery.
From August 2006 to June 2007, we treated 30 con­
secutive patients with flexor tendon injury in zone 2
using the Lim/Tsai surgical repair and the postsurgical
“stop and go” motion protocol. Exclusion criteria into
this review were the same as given earlier1; 26 long
finger injuries (involving 25 FDP and 14 FDS tendons)
and 9 thumbs were included. The surgeon initially
decided on which rehabilitation protocol was used,
taking in account the severity of the injury and the
quality of the repair.
In this most recent cohort of patients, we imple­
mented a new motion protocol—“stop and go” pro­
tocol, as detailed in Figure 13(A)-1. At the end of the
therapy (postsurgical 3 months ± 1 week) the outcome
underwent a six-strand zone 2 flexor tendon repair and
early active motion (51 digits in 46 patients) and “stop
and go” rehabilitation protocols (35 digits in 30
patients).
The results were compared to the results of zone 2
flexor tendon repair with the two-strand modified Kessler
repair combined with a Kleinert-Duran regimen in 25
patients (30 digits) between 1998 and 2002.1 Both
groups included consecutive patients who sustained
sharp and complete flexor digitorum profundus (FDP)
tendon lacerations in zone 2, with or without concomi­
tant flexor digitorum superficialis (FDS) tendon lacera­
tions or neurovascular damage. Injured tendons in these
patients were repaired surgically within 2 days after
trauma and postoperative therapies of the patients were
continued for a minimum of 8 weeks (Table 13[A]-1).
During the follow-up, grip strength (kg) was mea­
sured using a hand-held Jamar Dynamometer (Preston,
Jackson, MI). Total active motion (TAM) of each oper­
ated finger without secondary surgery was recorded. The
flexion of each involved joint was measured first when
the patient attempted to make a complete fist; the exten­
sion deficits were measured afterward. The original
Strickland grading system was used to assess final TAM.8
The functional results were recorded at a mean of 12
weeks postoperatively in both groups (range: Lim/Tsai
repair group, 9 to 17 weeks; Kessler repair group, 8 to
16 weeks). The follow-up period was determined on the
basis of collected data of the Kessler repair group; the
retrospectively collected data of this group provided
Table 13(A)-1  Patient Details
Groups
Lim and Tsai Method
Kessler Method
Core suture method
Lim and Tsai (six-strand)
Modified Kessler (two-strand)
Postoperative care
Kleinert-Duran regimen with place-and-hold
exercises
Kleinert-Duran regimen
Patients
46 (8 women, 38 men)
25 (8 women, 17 men)
Age (range)
32 years (13–74 years)
38 years (16–82 years)
Injured hand
Dominant
22
10
Nondominant
24
11
Unknown
—
4
Injured digits
51 (13, 9, 7, 22)*
26 (6, 7, 6, 7)*
Tendon injuries
  Isolated complete FDP
24
10
  Complete FDP and partial FDS
9
3
  Complete FDP and complete FDS
18
13
Neurovascular damage (digits)
3
13
Therapy delay (range)
0.5 day (0–2 days)
0.3 day (0–1 days)
*The numbers given in the parentheses are in the order of the index, middle, ring, and little fingers.

118
Section 2:  Primary Flexor Tendon Surgery
Figure 13(A)-1  Decision making and rehabilitation.
Repair reliable and free of tension?
DECISION MAKING AND REHABILITATION
No
Day 0
Day 0 to 1
Day 2 to 5
Day 6 to 24
Week 3.5
Week 6 to 8
Week 9 to 12
Unclear
Yes
No
No
Yes
Yes
GREEN: early active
flexion
YELLOW: place and hold,
passive tenodesis
RED: passive flexion,
active extension
Cobra splint (30° wrist flexion, MCP 0° extension), rubber band fixed to injured finger.
Therapy starts for all: passive flexion, active extension
Patient compliant? Injury site free of additional tissue resistance?
Place and hold exercise,
wrist tenodesis exercise under
surveillance of therapist
Patient compliant?
Tenodesis exercise with active
flexion. Active flexion in splint
3 to 5 weeks postoperatively: splint completely removed, rubber band fixed to wrist bandage
Continue exercises according to red/yellow/green, wrist free active motion
5 weeks postoperatively: rubber band removed
Continue exercises, full active flexion without resistance.
8 weeks postoperatively: start of exercises against resistance
Increasing resistance step by step to regain force. If necessary passive full extension
12 weeks postoperatively: full resistance allowed
Control of exercises: passive
flexion, active extension

119
Chapter 13A:  The Bern Experience
and understands German, French, or English. “Stop and
go” is used for lesions in zones 1 to 4; the wrist teno­
desis exercises are not performed for zone 5. Immedi­
ately after surgery, all patients receive a dorsal “cobra”
splint in 30° to 40° wrist flexion, with metaphalangeal
(MP) and interphalangeal (IP) joints in 0° (Figure
13[A]-3A).
Red: Passive Flexion, Active Extension.
The patient is instructed to perform passive flexion
(three times a day) and active extension (hourly) of all
fingers. The extension of involved digits should reach
the dorsal splint (0° in all finger joints) (Figure 13[A]-
3B–E). The goal of passive flexion is to make the
involved digits reach the palm.
The exercises are monitored by hand therapists at
least once a week, and continue to postoperative 3.5
weeks. The splint is then removed to allow active mobi­
lization of the wrist. The rubber band is fixed to a wrist
bandage for another 1.5 weeks. After 5 weeks the patient
is instructed to actively flex and extend fingers. Exercises
against resistance or passive full extension are not yet
allowed. If a passive extension deficit is noted, a static
or dynamic extension splint is adapted. At 8 weeks,
exercises against slight resistance are started. Over the
next 4 weeks, the resistance is gradually increased. Full
was measured using the original Strickland classification
for the fingers and the Buck-Gramcko classification for
the thumbs.
OPERATIVE TECHNIQUES
After Bruner zigzag incisions, the core suture was
achieved with the six-strand Lim/Tsai5,6 double-loop
technique with polyamid (4-0 Supramid; S. Jackson,
Alexandria, VA) and an epitendinous running suture
with polypropylen (5-0 Prolene) (Figure 13[A]-2). The
two slips of the FDS tendon were repaired with the use
of simple core Kessler sutures with polyamid single
suture (4-0 Supramid). No repair of the tendon sheath
was performed.
POSTOPERATIVE CARE
Therapists decide after consulting the surgeon as to
which protocols to be used depending on postoperative
hand conditions (swelling, pain) and the compliance of
the patient. Therapists may change the protocols during
the process of rehabilitation (see Figure 13[A]-1).
The Staged Rehabilitation Group:
“Stop and Go”
Conditions for the “stop and go” program are that the
patient is older than 12 years and that the patient speaks
Figure 13(A)-2  Technique of the six-strand core and running suture tendon repairs.

120
Section 2:  Primary Flexor Tendon Surgery
Figure 13(A)-3  A, Cobra splint and rubber band. B–E, Passive flexion. F, Place and hold (yellow). G, H, Tenodesis exercise
(yellow and green). I, Active flexion (green).
A
B
C
D
E
F
G
H
I

121
Chapter 13A:  The Bern Experience
motion, evaluated by the original Strickland classifica­
tion system, rendered 21 of 50 excellent and 18 of 50
good results in the group of Lim/Tsai repair compared
to 4 of 21 and 5 of 21 in the group of Kessler repair. The
TAM of the group of Lim/Tsai was 141.4°, which is
significantly better (p = 0.013) than the TAM of 123.3°
in the Kessler group. In the group of Lim/Tsai, 14 of 50
fingers (12 of 45 patients) (28%) necessitated an exten­
sion splint compared to 8 of 21 fingers (8 of 20 patients)
(38%) in the group of Kessler. On average, extension
splinting was applied around 8.5 weeks postoperatively.
The average extension lag was 20.7° in the group of
Lim/Tsai and 18.8° in the group of Kessler before splint­
ing. Twelve weeks postsurgery, the remaining extension
deficits of the interphalangeal joints were 12° and
16.4°, respectively, demonstrating no statistically sig­
nificant difference between the two groups. Using the
linear model, in the group of Lim/Tsai, the grip strength
was significantly better (p = 0.02), and the average time
of treatment for long fingers was significantly shorter
compared to the group of Kessler (p < 0.0001).
In the staged rehabilitation (“stop and go”) group,
48 flexor tendon repairs in 26 long fingers and 9 thumbs
were evaluated after 3 months; 14 fingers were treated
with the green, 9 fingers using the yellow and 3 using
the red protocol. Of 9 thumbs, 6 were rehabilitated with
the green, 1 with the yellow and 2 with the red protocol.
Nine (35%) flexor tendon repairs were rated excellent,
7 (27%) good, 6 (23%) fair, and 4 (15%) poor using
the original Strickland criteria. The mean active range
of motion at the end of therapy was 90° of flexion and
10° hyperextension for the MP joint, whereas it was
90° of flexion but an extension lag of 10° for the PIP
joint and 43° of flexion and full extension for the DIP
joint. Grip strength compared to the contralateral hand
was 72%.
The results of the FPL repair were good or excellent
in 90% (6 excellent, 2 good, 1 fair) of digits. The mean
resistance is allowed after 12 weeks. The passive flexion
and active extension (red) is a basic program. The yellow
and green programs described next are built up on it,
with addition of active motion components.
Yellow: Place and Hold
To the basic program (red), place-and-hold exercises are
added. The place-and-hold exercises are done after the
basic exercises to decrease tissue resistance. In doing
place-and-hold exercises, all fingers are passively flexed
and actively hold in the flexed position for one second
(Figure 13[A]-3F). During the therapy session, the
splint is removed to perform wrist tenodesis exercises to
initiate tendon gliding: active extension of the wrist
while the fingers stay relaxed (Figure 13[A]-3G–I). After
3.5 weeks, the splint is removed. The rubber band is
fixed to a wrist bandage and the exercises are continued
in the same way. After 5 weeks, the therapy is continued
in the way as described in the red protocol.
Green: Early Active
In addition to the basic exercises, the patient starts cau­
tiously with active flexion in the splint to reach a middle
position (every joint around 60° flexion).
If the patient is cooperative and able to follow the
directions given by the surgeon/therapist, he is instructed
to remove the splint and to perform the wrist tenodesis
exercise with active finger flexion: active wrist extension
with complete active finger flexion without resistance.
When the patient is not considered to be compliant, he
is “downgraded” to the yellow or even the red protocol
at any time in the course of therapy.
The control and progression of rehabilitation remain
the same as for red and yellow.
OUTCOMES
Our results of the two- and six-strand repair are sum­
marized in Table 13(A)-2. The assessment of range of
Table 13(A)-2  Results of Repairs of Completely Lacerated FDP Tendons Using Two Suture Methods
Evaluations
Lim and Tsai Group
Kessler Group
p values
TAM
PIP + DIP joints
141° (90°–195°)*
123° (75°–190°)
.013
MP + PIP + DIP joints
232° (190°–290°)
213° (155°–290°)
.013
Extension deficit
23/50 digits
11/21 digits
NS
PIP + DIP joints
12° (5°–30°)
16° (10°–25°)
NS
Extension
14/50 digits
8/21 digits
NS
Grip strength
Injured hand
34.6 kg (14–60 kg)
30.3 kg (14–60 kg)
NS
Uninjured hand
45 kg (22–70 kg)
46.3 kg (22–66 kg)
NS
Difference (uninjured-injured)
10.4 kg (−40 to 40 kg)
16.1 kg (−6 to 34 kg)
.02
Duration of therapy
112 days (62–230 days)
209 days (83–496 days)
<.001
*The numbers given in the parentheses are ranges. NS, not significant.

122
Section 2:  Primary Flexor Tendon Surgery
Kessler Group
The rupture rate in the group of Kessler was 3 of 26
fingers (11%). The complication rate was 6 of 26 fingers
(23%). The complication rate (including dehiscence and
tenolysis) was significantly lower (Lim/Tsai: 4%; Kessler:
23%) in the group of Lim/Tsai repair (p = 0.048).
In the staged rehabilitation group “stop and go” the
rupture rate was 2 of 48 (4%). One rupture occurred
while the patient was fighting with others during a
nightmare.
DISCUSSION
Gill and colleagues5 conducted a human cadaveric study
and showed the superiority of the Lim/Tsai four-strand
repair over two- or four-strand repair techniques with
regard to tensile strength. Xie and coworkers7 compared
different six-strand suture configurations and showed
that in vitro the modified Savage and the Tang suture
have greater tensile strength than the Lim/Tsai suture,
but they also concluded that the Lim/Tsai suture has the
mechanical strength for unrestricted active finger flexion.
The loop-suture technique simplifies flexor tendon
active range of motion of the thumb was 61° of flexion
and 5° hyperextension in the MP joint and 39° of
flexion in the IP joint but with a slight extension lag of
5° (Table 13[A]-3).
COMPLICATIONS
All eight patients requiring secondary surgery had com­
plete lacerations of both the FDP and the FDS tendons.
Table 13(A)-4 details the injured finger and the lacera­
tion site within zone 2 according to Tang’s subdivision
of zone 2.9
Lim/Tsai Group
One 30-year-old patient with impaired flexion and
extension of the middle finger required a tenolysis
with FDS resection 9 months after primary repair. One
patient sustained a rupture of the repaired index FDP
and was reconstructed with a palmaris longus tendon
graft 2 months after the primary repair. The rupture
rate in the group of Lim/Tsai was 1 of 51 fingers (2%)
and the complication rate including tenolysis was 2 of
51 (4%).
Table 13(A)-3  Results of Staged Rehabilitation After Flexor Tendon Repairs in 26 Fingers and 9 Thumbs
26 Fingers (Strickland Criteria)
9 Thumbs (Buck-Gramcko Criteria)
Functional Grades
Results
Protocol
Functional Grades
Results
Protocol
Excellent
9 (35%*)
9 green
Excellent
6 (66%)
6 green
Good
7 (27%)
4 green, 3 yellow
Good
2 (18%)
1 yellow, 1 red
Fair
6 (23%)
6 yellow
Fair
1 (9%)
1 red
Poor
4 (15%)
3 red, 1 green
Poor
0
—
Grip Strength
72% compared to the opposite
site
Pinch Strength
85% compared to the
opposite site
*Percentage of the fingers rated in each grade is given in the parentheses.
Table 13(A)-4  Tendon Injury Sites and Complications Using Tang’s Division of Subzones
Groups
Numbers of
Complications
Age
Finger
Lacerations Within
Tang’s Subzones
Time of Secondary Surgery (Months
After Last Surgery)
Lim/Tsai
2 (out of 51 fingers)
1 tenolysis
—
1 rupture
30
Long
2B
9 months
—
—
26
Index
2B
—
—
2 months
Kessler
6 (out of 26 fingers)
1 tenolysis
2 dehiscence
3 ruptures
53
Index
2B
9 months
—
—
18
Long
2D
—
7 months
—
46
Ring
2B
—
7 months
—
30
Long
2D
—
—
2 months
59
Long
2B
—
—
4 months
82
Ring
2B
—
—
1 month

123
Chapter 13A:  The Bern Experience
of Kessler. Compared to the 50% to 100% good and
excellent results of other studies,13-21 the outcome in
the group of Kessler repair seemed to be rather poor.
The results of the group of Lim/Tsai are in line with the
above mentioned reports of zone 2 tendon repairs, espe­
cially in view of the longer follow-up of at least at 6 to
12 months in these studies. The only report on Lim/Tsai
sutures with place-and-hold exercises in zone 2 is by
Lim and Tsai.6 They achieved 81% good/excellent results
after 7 months assessed by the revised Strickland criteria
compared to 100% of good/excellent results in the
group of Lim/Tsai and 91% in the group of Kessler after
3 months in our series when using the revised Strickland
criteria.
We evaluated a six-strand suture repair technique and
the benefit of place-and-hold exercises on digital func­
tion compared to a two-strand repair without place-
and-hold exercises. In an additional group of patients,
“stop and go” early active mobilization protocol pro­
duced better outcomes compared with the previous
patient groups with place-and-hold or passive flexion
and active extension protocols. In nearly 50% of the
patients, the surgeons and the therapists decided not to
use the early active (green) but rather the place-and-hold
(yellow) or Kleinert/Duran (red) rehabilitation program
despite the use of a strong six-strand repair. The actual
effects of wound conditions and swelling on the resis­
tance to tendon gliding can be difficult to estimate in
due course. In our experience, it is better to have a few
options for the rehabilitation protocols to select accord­
ing to patients’ wound conditions and degree of hand
swelling. Furthermore, we should consider the capabil­
ity of the patient to perform the exercises to reduce the
likelihood of repair ruptures.
Our experience with “stop and go” protocols indi­
cates that the protocols allow individual adjustments of
postoperative rehabilitation, thus optimizing outcomes
after flexor tendon repair. With these protocols, rehabili­
tation can be adapted to different patients’ conditions,
leading finally to good and excellent results.
repair compared to the modified Savage repair and does
not use superficial knots like the Tang suture. Given the
tensile strength of the Lim/Tsai suture, our comparison
of the six-strand and two-strand repair techniques1 dem­
onstrated a better outcome without increasing the risk
of tendon ruptures using place-and-hold exercises post­
operatively in the Lim/Tsai suture group. This group
demonstrated a significantly better TAM. There was no
increased rate of ruptures, nor did it differ significantly
between the two groups. Even without a statistically rel­
evant difference, there may still be a clinical difference
given the drop of the rupture rate from 11% to 2%
between the Kessler and the Lim/Tsai groups. The
rupture rate in group of Lim/Tsai and in the group of
Kessler is in line with the published rupture rate of 4%
to 10% in zone 2 mentioned in the review of Tang.10
Furthermore, the overall complication rate (including
tenolysis and dehiscence) was significantly lower in the
group of Lim/Tsai.
Tang and colleagues11 performed a biomechanical
study showing that gliding curves of a small diameter
and gliding over the rim of a major pulley are associated
with an increased rupture risk. Dowd and coworkers14
stated that these characteristics were typically found in
zone 2B repairs and repairs of tendons in the little finger
(zone 2B defined by Tang9: subzone from the proximal
margin of the FDS insertion to the distal border of the
A2 pulley). In the clinical study by Dowd and col­
leagues,12 32 of 42 fingers requiring rerepair had injuries
in zone 2B and/or in the little finger. In our study, no
repair ruptured in the small finger. Four of six patients
with ruptures or dehiscences, had undergone repair in
zone 2B (see Table 13[A]-4), which seems to support
Dowd and colleagues’ conclusion of zone 2B as the repair
site at highest risk. The remaining two patients required
repairs in zone 2D (subzone from the proximal border
of the A2 pulley to the proximal margin of zone 2).
Using the original Strickland classification, the group
of Lim/Tsai demonstrated 39 of 50 (78%) good and
excellent results compared to 9 of 21 (43%) in the group
References
1. Hoffmann GL, Büchler U, Vögelin E: Clinical results of flexor
tendon repair in zone II using a six-strand double-loop tech­
nique compared with a two-strand technique, J Hand Surg
(Eur) 33:418–123, 2008.
2. Strickland JW: The scientific basis for advances in flexor
tendon surgery, J Hand Ther 18:94–110, 2005.
3. Al-Qattan MM, Al-Turaiki TM: Flexor tendon repair in zone
2 using a six-strand ‘figure of eight’ suture, J Hand Surg (Eur)
34:322–328, 2009.
4. Trumble TE, Vedder NB, Seiler JG III, et al: Zone-II flexor
tendon repair: A randomized prospective trial of active place-
and-hold therapy compared with passive motion therapy,
J Bone Joint Surg (Am) 92:1381–1389, 2010.
5. Gill RS, Lim BH, Shatford RA, et al: A comparative analysis
of the six-strand double-loop flexor tendon repair and three
other techniques: A human cadaveric study, J Hand Surg (Am)
24:1315–1322, 1999.
6. Lim BH, Tsai TM: The six-strand technique for flexor tendon
repair, Atlas Hand Clin 1:65–76, 1996.
7. Xie RG, Zhang S, Tang JB, et al: Biomechanical studies of 3
different six-strand flexor tendon repair techniques, J Hand
Surg (Am) 27:621–627, 2002.
8. Strickland JW, Glogovac SV: Digital function following flexor
tendon repair in Zone II: A comparison of immobilization
and controlled passive motion techniques, J Hand Surg (Am)
5:537–543, 1980.
9. Tang JB: Flexor tendon repair in zone 2C, J Hand Surg (Br)
19:72–75, 1994.
10. Tang JB: Clinical outcomes associated with flexor tendon
repair, Hand Clin 21:199–210, 2005.

124
Section 2:  Primary Flexor Tendon Surgery
trolled active motion regimen, J Hand Surg (Br) 19:607–612,
1994.
17. Klein L: Early active motion flexor tendon protocol using one
splint, J Hand Ther 16:199–206, 2003.
18. Lee H: Double loop locking suture: a technique of tendon
repair for early active mobilization. Part II: Clinical experi­
ence, J Hand Surg (Am) 15:953–958, 1990.
19. May EJ, Silfverskiold KL, Sollerman CJ: Controlled mobiliza­
tion after flexor tendon repair in zone II: A prospective com­
parison of three methods, J Hand Surg (Am) 17:942–952,
1992.
20. Silfverskiold KL, May EJ: Flexor tendon repair in zone II with
a new suture technique and an early mobilization program
combining passive and active flexion, J Hand Surg (Am)
19:53–60, 1994.
21. Small JO, Brennen MD, Colville J: Early active mobilisation
following flexor tendon repair in zone 2, J Hand Surg (Am)
14:383–391, 1989.
11. Tang JB, Xu Y, Wang B: Repair of strength of tendons of
varying gliding curvature: A study in a curvilinear model,
J Hand Surg (Am) 28:243–249, 2003.
12. Dowd MB, Figus A, Harris SB, et al: The results of immediate
re-repair of zone 1 and 2 primary flexor tendon repairs which
rupture, J Hand Surg (Br) 31:507–513, 2006.
13. Bainbridge LC, Robertson C, Gillies D, et al: A comparison
of post-operative mobilization of flexor tendon repairs with
“passive flexion-active extension” and “controlled active
motion” techniques, J Hand Surg (Br) 19:517–521, 1994.
14. Baktir A, Turk CY, Kabak S, et al: Flexor tendon repair in zone
2 followed by early active mobilization, J Hand Surg (Br)
21:624–628, 1996.
15. Cullen KW, Tolhurst P, Lang D, et al: Flexor tendon repair in
zone 2 followed by controlled active mobilisation, J Hand
Surg (Br) 14:392–395, 1989.
16. Elliot D, Moiemen NS, Flemming AFS, et al: The rupture
rate of acute flexor tendon repairs mobilized by the con­

125
David Elliot, MA, FRCS, BM, BCh
B
The Chelmsford Experience
THE ST. ANDREW’S UNIT
As a basis for modern practice, this is only likely to
improve results if surgery is carried out by adequately
trained surgeons and followed by early mobilization by
skilled hand therapists, not general physiotherapists.
The Chelmsford unit has tried to progress along these
lines for the past 20 years in both respects. The growth
of specialist hand therapy during this period, both
within the unit and, more generally, throughout the
United Kingdom, has been an essential factor in this
change. The development of a dedicated all-day trauma
theater and increasing numbers of consultant hand sur­
geons and training surgeons at a senior (fellow) level
involved in this surgery have also been integral to main­
taining the quality of service with increasing numbers
of referrals. Emergency services locally are arranged to
relocate these injuries almost entirely to our unit from
the surrounding accident and emergency departments
of several large peripheral towns and the suburbs of East
London, which have a combined population of around
4 million people.
THE PROBLEMS OF PRIMARY FLEXOR
TENDON REPAIR
Repair of the divided flexor tendon to achieve normal,
or near normal, function is a problem that has not yet
been solved. Primary flexor tendon surgery remains
technically difficult, with each result still being uncer­
tain. There have been about 20 methods of assessing
flexor tendon results described in the hand literature
since 1950.4 This repeating need to reevaluate our
methods of assessment has come not from attempts to
keep up with improvement of the results over the years
but from a repeating need to quantify how much we
should reasonably downgrade our expectations to
accommodate for the imperfections of our treatment.
Over and above the actual technical difficulties of repair­
ing tendons, we face the complications of rupture and
adherence of repairs during healing and these two prob­
lems have dominated thought on this subject for a
century. “Spot-welding” by scar adhesions can occur
anywhere along the length of a flexor tendon, but it is
a particular problem in the fingers themselves, where
the flexors are confined within the tendon sheath in a
system as finely bored as the pistons in an engine. This
requires that the tendons be mobilized throughout the
OUTLINE
This chapter reviews the research into primary flexor
tendon surgery chronologically through from 1989 to
2010 in the Hand Surgery Unit of the St Andrew’s
Centre for Plastic Surgery, Chelmsford, UK, explaining
the changes made and the thinking behind them.
Movement should be instituted with care and judgment.
In the first week, it will prevent the incision from healing
and encourage infection. If begun late, adhesions will
already have immobilized the tendon. Rough, extreme and
continuous movements will cause fibrin and scar tissue to
form and bind the tendons, and also cause the sutures to
cut out. Rest favors a natural repair, with a minimum of
inflammatory reaction, but, also, allows adhesions to form
to all raw surfaces. Movement encourages the formation
of synovial membranes over the raw surfaces. It would
seem that a moderate amount of intermittent movement,
with as long an excursion as practical, interspersed by rest,
will yield the best results.
Sterling Bunnell MD, San Francisco, 1918
HISTORY
Although Bunnell (1918) wrote on primary repair and
early, albeit guarded and intermittent, active mobiliza­
tion, his subsequent experience in the 1920s presum­
ably led to the dictate that flexor tendons divided in the
tendon sheath of the fingers should not be repaired
primarily but treated by delayed tendon grafting. This
practice dominated the practice of flexor tendon surgery
for 40 years. The past 50 years is notable for the reversal
of this policy and recognition that results after primary
or delayed primary flexor tendon repair, that is within
a few days of tendon division, can be better than after
delayed tendon grafting, provided early surgery is com­
bined with early mobilization of the repaired tendons,
a change largely pioneered by Verdan,1 Young and
Harman,2 and Kleinert and colleagues.3 Although there
is ongoing debate about the details of technique, the
central tenet of modern flexor tendon surgery is to repair
and move the flexor tendons within a few days of injury.
While all flexor tendon surgery is complicated, it is
simplest in the newly injured and unscarred digit and
the results of correctly rehabilitated primary repairs are
likely to be the best attainable.

126
Section 2:  Primary Flexor Tendon Surgery
rehabilitation, in respect of simplifying rehabilitation to
a level commensurate with the availability of therapy in
our own unit and likely to be available worldwide. The
results of these, and subsequent reports throughout the
1990s, confirmed a rupture rate of around 5% when
using variants of the Belfast regimen,5,26-30 which was
similar to that reported at the time by units worldwide
using the Kleinert regimen.26,29,31-35
PASSIVE MOBILIZATION
The other alternative to the Kleinert technique of mobi­
lization, introduced in the United States by Duran and
Houser (1975) and supported by Strickland and Glogo­
vac (1980), in which the fingers were only mobilized
passively by a therapist, or the patient’s other hand,
was never popular in the United Kingdom as it was
very labor (therapy) intensive, with no seeming advan­
tages.36,37 A common debate at the time which, to my
knowledge, has never been settled, was whether the
tendons actually moved significantly with this regimen
or simply bunched up as the fingers were passively
flexed. Another factor that made it unattractive was the
fact that the first report included a 14% rupture rate,36
while the second had only 56% good and excellent
results,37 both of which are unacceptable compared with
published results at the time using the Kleinert regimen
and, subsequently, the Belfast regimen. The most
common use now of the Duran Houser idea is in helping
Kleinert and Belfast regimens push for better results at
the extremes of movement.
ST. ANDREW’S EARLY RESULTS—FINGERS
Our own early results using a two-strand Tajima modi­
fication of the Kirchmayer, or Kessler, core suture19,38 of
3-0 or 4-0 polypropylene (Prolene), in which the suture
is tied with a single intratendinous knot, a simple con­
tinuous running circumferential suture of 5-0 or 6-0
nylon (Ethilon), or polypropylene, and a modification
of the Belfast regimen (Figure 13[B]-1), were reported
in 1994.28 Over a period of 312 years, 233 patients were
treated for complete divisions of flexor tendons in zones
1 and 2 within 24 hours of admission following emer­
gency referral. The patients included 58 complete
tendon divisions in 58 fingers in 54 patients in zone 1
and 259 tendon divisions in 166 fingers in 149 fingers
in zone 2. A later study extended this survey to include
508 patients with 840 acute complete flexor tendon
divisions in 605 fingers treated in the same manner
between June 1989 and December 1996.29 These reports
were both focused on the problem of rupture. In the
first report, an overall rupture rate of 5.8% was achieved,
with a rupture rate for zone 2 injuries of 5.4% and for
zone 1 injuries of 6.8%, confirming our belief that the
regimen was safe for use as an alternative to Kleinert-
type regimens for mobilization of zone 1 and 2 finger
flexor tendon injuries. In the larger survey, after
period immediately after repair when tendon continuity
depends almost entirely on the strength of the sutures,
as healing of the flexor tendon takes about 3 months.
Unfortunately, this period is sometimes longer than that
for which the hand can be kept free of activities, or
accidents, liable to snap the repair. In this unit, our
main research interests have been to eliminate rupture
of the tendons while maintaining a policy of enthusias­
tic early active mobilization. The assumption support­
ing this philosophy is that the results will be better with
increasing early movement through the first 5 weeks,
albeit within the protective environment of a dorsal
splint, provided the sutures hold and rupture does not
occur. Our research over 20 years has aimed at liberating
rehabilitation from unnecessary constraints while, coin­
cidently, reducing the rupture rate after primary repair.
EARLY ACTIVE MOBILIZATION
The author’s interest in early active mobilization comes
from his training with McGrouther in Glasgow, then
with Brown and Black in Newcastle, prior to arrival in
the Chelmsford unit. The latter part of my training coin­
cided with the publishing of an article by the hand
surgeons in Belfast, not far away, in which they described
mobilization after routine zone 2 flexor tendon repairs
in a Kleinert traction splinting system but without the
elastic bands (i.e., actively moving the fingers when
flexing as well as when extending).5 This was not actually
new as many before had either never used rubber bands
or tried to get rid of them,6-25 although always stressing
the use of some variant of suture technique to make the
repair stronger, presuming this would be necessary to
withstand early active movement. What the Belfast sur­
geons identified was the fact that the sutures did not
need to be stronger to allow early active mobilization
in both directions. The desire to be free of the rubber
bands had been prevalent for years, largely because of
the problems arising from the flexed resting position of
the proximal interphalangeal joints in Kleinert traction
and, also, because of the difficulties in managing Klein­
ert traction. It was also realized that many patients never
actually used the rubber bands to passively flex but
simply flexed their fingers actively, even when the bands
were correctly tensioned, which was often only for 5
minutes after leaving the therapy department. This stim­
ulated me to repeat the Belfast experiment. This is
recorded in an article26 comparing patients mobilized in
a passive flexion-active extension, or “Kleinert” regimen,27
with patients mobilized in an active flexion-active exten­
sion, or “Belfast” regimen,5 after the same repair with a
two-strand modified Kessler core suture and a simple
running circumferential suture. This study, performed
between 1986 and late 1987 (although only published
much later), and the study from Sheffield, UK, reporting
the results of their repeat of the Belfast experiment28
convinced me that this was the way forward for

127
Chapter 13B:  The Chelmsford Experience
exclusion of 68 patients who did not complete the
8-week rehabilitation program, 440 patients with 728
complete tendon divisions in 526 fingers were assessed.
Twenty-three patients suffered rupture of 28 tendons in
23 fingers, an overall rupture rate of 4%. One hundred
and twenty-nine fingers with zone 1 injuries had a
rupture rate of 5% and 397 fingers with zone 2 injuries
had a rupture rate of 4%. The good and excellent results
in the final year of the first study, assessed using the first
Strickland method of assessment,37 of 62.5% for zone 1
injuries and 79.4% for zone 2 injuries confirmed that
these rates of rupture were not being achieved at the
expense of increased protection and poor mobility.
These studies confirmed that early active motion was as
safe as any current regimen, with results comparable to
those of previous studies in terms of both rupture and
mobility in a considerable number of fingers, most
other studies in the literature being much smaller in
size. At the time, we wrote that we believed the Belfast
type of rehabilitation was both simpler and less expen­
sive to maintain than the Kleinert type of rehabilitation
regimen. We were no longer concerned about the safety
of the Belfast regimen, something, which still persists
elsewhere, particularly in the United States. However, we
Figure 13(B)-1  Original Billericay/Chelmsford variation of
the Belfast splint with (A) the fingers resting in extension,
and (B) the fingers actively flexing.
A
B
had also reached the conclusion that argument over
which was the best of the two active regimens was prob­
ably unproductive.
THE 5% RUPTURE RATE
Throughout this period, we were concerned by the
seemingly static state of acute flexor tendon repairs
being reported worldwide in those units publishing
results. With few exceptions, most studies discussing
acute flexor tendon repair and early mobilization
reported a rupture rate of between 3% and 6%. In
studies of less than 100 patients, these figures indicated
negligible differences in the number of patients with
ruptured tendon repairs in different units in different
countries and continents, using a multitude of suture
techniques and variations of the basic regimens of early
postoperative mobilization. Even taking into account
the variations in methods of assessment used at the
time,4,39-41 the similarity of the results in different studies
showed that an adequately trained, but not necessarily
experienced, surgeon, using a routine repair of divided
flexor tendons, whether using the Kirchmayr/Kessler
core suture or following the technique described by
Tsuge,42,43 and with good therapists, would achieve 70%
to 80% excellent, or good, results and suffer a rupture
rate of about 5%. The only identifiable way of improv­
ing results in the early 1990s, although having little
effect on rupture rate, seemed to be to increase post­
operative supervision, generally believed to be the
explanation of the excellent results achieved by Chow
and his colleagues, dealing with military personnel.32 It
was thought at the time that this was unattainable in
civilian practice, until the civilian surgeons and thera­
pists in Göteborg, in Sweden, showed that—with a
stronger technique of circumferential suturing and a
more rigorous therapy regimen, incorporating features
of the Kleinert, the Duran-Houser, and the Belfast
regimens—this was not true.44 However, this study still
included two ruptures in 55 repairs: stronger sutures
and more complex rehabilitation still had not solved
the problem of rupture of primary repairs.
ETIOLOGY OF RUPTURES
Our second article was intended to look further at this
seemingly unconquerable rupture rate by examining the
third factor in the problem of rupture: the patient. We
analyzed the 23 patients whose primary repairs rup­
tured between 1989 and 1996: two tendons ruptured
during sleep, four patients had an accident that was not
their fault, and five patients claimed they were exercising
as instructed at the time of rupture. There were reasons
to doubt the truth of this information in three cases.
However, we gleaned definite information that 11
patients’ repairs ruptured while using the hand for a
variety of tasks, ranging from lightweight activities such
as lifting a newspaper to unreasonable activities such as

128
Section 2:  Primary Flexor Tendon Surgery
we have not had time to research this fully and have
only gone halfway from the original flexed position
to a straight wrist splint. The actual therapy regimen
has not changed since that described in 1994 (Box
13[B]-1).30 The time in the splint remains 5 weeks, fol­
lowed by 3 weeks weaning from the splint. Light activi­
ties start at 8 weeks, with heavy lifting only after 12
weeks. This 5-week period of total protection seems to
be in accord with our findings in respect of the timing
of rupture of repairs.4,28,46
RUPTURE RE-REPAIR
Our interest in the rupture of repairs was taken further
in a more recent review of all ruptures of zone 1 and 2
primary flexor tendon repairs performed in our unit
between 1989 and 2003.46 Although concern about
tendon rupture had been one of the major determinants
in the evolution of the various techniques of tendon
suture and early postoperative mobilization throughout
the past 10 years of the twentieth century, there was still
almost no information in the literature about the etiol­
ogy of tendon rupture.28,47 The intention of our 2006
report46 was to analyze in further detail (1) the reasons
for tendon rupture during the early mobilization period
and (2) the outcome of immediate re-repair, with a view
moving a wardrobe. In other words, just under 50% of
the ruptures had occurred as a result of patient noncom­
pliance. This injury mainly occurs at an age and in a
social group for which improving compliance is likely
to be difficult. Nevertheless, all patients have subse­
quently been told the causes and incidence of failure
before 2 months, with need for further surgery, by the
author on the morning after surgery as a routine. In this
era, it would seem reasonable that the patient should
have the likely consequence of noncompliance spelled
out clearly before rehabilitation begins!
The group labeled “uncooperative patients” includes
adults and children who do not cooperate and small
children who cannot. As adults constitute by far the
greater proportion of patients who sustain flexor tendon
injuries, they are the major concern. In any group of
patients, there will always be rule breakers, those who
resent authority, and those without the discipline to
adhere to the strict rehabilitation regimen demanded
after this injury. Psychological manipulation and more
time are the only direct means we have of improving
the results of these patients and it is debatable whether
we can change this factor more than a little. However,
among this group are some with low pain thresholds,
poor social circumstances, or a low level of comprehen­
sion and we can, sometimes, help these individuals
more, given adequate resources.
Most ruptures in our study occurred with the splint
in place. These tendon repairs might have been pro­
tected from rupture by better mechanical obstruction of
the palm. Rubber bands across the palm have a definite
obstructing action, which was not present in the original
technique of early active motion.5 However, all of our
patients at that time wore a modified Belfast splint,
which included wide thermoplastic bars across the open
side of the splint, running from the distal edge back to
the volar aspect of the wrist and known locally as “beer-
can bars” (see Figure 13[B]-1).30 These provided a
similar obstruction to grasping to that of the rubber
bands of the Kleinert splint. Attempts to increase this
feature of splinting and/or attempts to make splints
impossible to remove might interfere with rehabilita­
tion and would probably still fail in a proportion of
patients. They would certainly have little effect in those
who remove the splint to use the hand for grasping. In
the last five years, the ‘beer-can bars’ on our splints have
given way to a sheath of lightly elasticated material
which holds the fingers in extension against the dorsal
splint for most of the time, with the sheath being rolled
down into the palm for exercising of the fingers (Figure
13[B]-2).
THE SPLINTED WRIST POSITION
While accepting the work of Savage that the best posi­
tion for the wrist in respect of minimum firing of both
the flexor and extensor muscles is in slight extension,45
Figure 13(B)-2  Illustration of the current Billericay/
Chelmsford variation of the Belfast splint with (A) the fingers
resting in extension, and (B) the fingers actively flexing.
A
B

129
Chapter 13B:  The Chelmsford Experience
experienced in the emergency theater, was certain that
venting was correct and necessary in many cases. The
discussion of “venting” is taken further and, I believe,
to its logical conclusion in other chapters of this book
and in two review articles in the recent past.48,49 Analyz­
ing the sites along the tendon sheath were tendon injury
commonly occurs, Dr. Tang has described appropriate
pulley releases for each injury and accords this process
of pulley “venting” equal importance as the use of stron­
ger repairs in increasing the margin of safety of early
active mobilization.49 We believe the results of zone 1
primary flexor tendon surgery are equally dependent on
judicious venting of the A4 pulley.50
STRONGER REPAIRS
At that time, increasing the strength of our sutures
seemed likely to be the most effective preventative of
tendon rupture in this group of patients. The ability of
tendon sutures to withstand the forces of early move­
ment is, probably, the most fundamental limitation to
what can be achieved by early movement of primary
flexor tendon repairs by any technique. This has been
the second prong in the mechanical way forward since
Harmer, in Boston, in 1917, introduced a flexor tendon
core suture that he believed was sufficiently strong
to resist rupture and commenced immediate free
movement of the fingers postoperatively without any
splints,14 and, in the same year, Kirchmayr presented
his stronger suture, with the same purpose in mind.38
Our work on ruptures had convinced us, like others,
that we needed stronger sutures to continue aggressive
early active mobilization without this 5% rupture rate.
In the recent past, there had been numerous studies,
mostly experimental, describing a variety of means by
which this might be achieved. The suture changes can
be split, broadly, into those modifying the core suture
and those modifying the circumferential suture. Our
examination of the patients who had ruptured our
repairs simply confirmed what everyone had assumed
and highlighted a need to move toward clinical applica­
tion of the laboratory research into stronger sutures and
identify which of these suture modifications was suffi­
ciently practical to be used in clinical practice. Regret­
tably, few of the laboratory experiments of suture
configurations of the nineties have since been pro­
gressed to clinical studies by their authors.
ZONE 2 AS A BLACK BOX
Throughout the 1990s, we were not entirely happy with
the zone 2 model for investigation of the problem
further, although zone 2 had become the accepted
testing ground for mobilization techniques—and for
individual units! It was obvious that most studies
reported less than 50 cases and that it was difficult to
collect sufficient cases of zone 2 injuries alone in a
single unit to make a series. As a result, three things had
to identifying whether this should be an invariable
policy, whenever possible. Discussion of our views on
the management of ruptures of primary repairs of flexor
tendons in zones 1 and 2 in the fingers are considered
further in Chapter 19.
VENTING THE PULLEYS
In retrospect, a factor in achieving these results that
received no attention at the time but was, possibly, of
significance was that, from the earliest of the studies in
which I was involved, it had been routine to “vent”
pulleys as necessary to allow repairs to travel through a
full range of excursion on passive movement of the
finger after repair without impinging on the A2 or A4
pulleys. The conviction that this “made sense” followed
a private conversation as a trainee in the mid-1980s at
the Derby Hand Course with Dr. Strickland. At the time,
Lister and others were quite adamant that these pulleys
should remain entirely intact. Dr. Strickland seemed
less certain and I, knowing the problems I personally
Week 1—Discharged from hospital when pain controlled
by simple oral analgesics, patient able to do dressings
and achieving full extension to splint and active flexion
to 25% of full flexion. Instructed to carry out 10 active
flexion and extension exercises per hour.
Week 2—Seen by surgeons and therapists. Full extension
to splint and active flexion to 50% of full flexion. Ten
exercise repetitions per hour. Passive flexion exercises
started.
Weeks 3 and 4—Seen weekly by therapists only. Full
extension to the splint and progression to full range of
active flexion as soon as possible (usually achieved by
the end of week 3). Ten exercise repetitions per hour.
Passive exercises. Ultrasound started if necessary in
week 3.
Week 5—Seen by surgeons and therapists. Splint removed,
except at night and when risk to the hand (e.g., in
crowds). Wrist extension started, with fingers relaxed at
first.
Weeks 6 and 7—Seen weekly by therapists. Progression
to full range of movements of wrist and fingers.
Week 8—Splint discarded completely. Passive extension
exercises and dynamic extension splinting started if nec­
essary. All but heavy activities allowed, including driving.
Return to work (except heavy manual workers).
Weeks 10 to 12—Progressive return to heavy work by
week 12.
Box 13(B)-1 
The St. Andrew’s Early
Active Mobilization Regimen (1994)

130
Section 2:  Primary Flexor Tendon Surgery
However, we realized that the higher rupture rate might
make the FPL a good clinical model to test new sutures
and suture techniques. Using this model, we were able
to examine some of the new suture configurations being
described in laboratory experiments in a series of
studies,52-54 which are described in Chapter 16. Although
these reports elaborate an increasingly safer technique
for dealing with division of the FPL tendon, they were
undertaken largely to examine possible ways forward in
respect of the finger flexors. Ultimately, these clinical
experiments with the divided FPL achieved zero rupture
rates using two different suture techniques (a combina­
tion of a four-strand core suture55 and a Silfverskiöld
circumferential suture56) and Tang’s three Tsuge suture
repair.57,58
To us, this confirmed the likelihood that increase
in suture complexity would successfully reduce the
rupture rate during early mobilization after repair of the
finger flexor tendons and, like most others, we have
gone the way of increasing suture complexity. After a
dalliance with more complex circumferential sutures,
we came to the conclusion that these were too compli­
cated for trainees, who are likely to operate on these
cases both in our own unit and worldwide. The combi­
nation of a four-strand core suture and a complex cir­
cumferential sutures also gave rise to concern about the
bulk of the repairs and possible problems of resistance
to movement of the repaired tendon.59 This was sug­
gested by a slight drop in the excellent and good results
in this group of FPL repairs compared with previous
results. However, this problem was small. Of more sig­
nificance was the fact that these complex sutures are
more difficult to use in clinical practice. In our FPL
studies, this led to the use of Tang’s triple Tsuge suture
technique57,58 for FPL repair, as this is a less complicated
suture technique.
STRONGER SUTURES—DILEMMAS
Four-strand repairs have become the order of the day
for zone 1 and 2 finger flexor repairs at present in
Chelmsford. However, there remain two causes for
concern as we all move to more complex suturing. Reex­
amination of the clinical series reported over the past
25 years identifies the study in 1989 by Savage and Risi­
tano,25 which introduced Savage’s six-strand suture and,
with it, the search for the ideal multistrand suture that
would have the strength of the Savage suture but be
simpler to put into the tendon, as the series with the
lowest rupture rate of one rupture in 31 zone 2 fingers
and 2 thumbs (3%). The next lowest rupture rate was
in our series from Chelmsford in 1999, which reported
17 ruptures after zone 1 and 2 primary flexor tendon
repairs in 397 fingers (4%).31 This much larger series of
cases were repaired with only two-strand Kirchmayr/
Kessler core sutures and simple running circumferential
suturing, making the hard evidence for improvement of
happened. The first was that the total number of studies
remained small. The second was that most studies were
small in themselves and, in many cases, too small to be
of scientific value. The third was that the available
numbers were too small to analyze exactly what was
going on in the “black box” we called zone 2, as all the
results had to be put together to achieve a publishable
total. Zone 2 is far from homogeneous: there are eight
permutations of tendon injury in what we call a zone 2
injury. We ignore the three partial injuries and put all
those with at least one complete tendon division into
the black box marked “zone 2 injury”: there are actually
five different injuries in this box. In the 1990s, we
looked at this briefly and it looked as if there might be
differences in results for different injuries, with a com­
plete flexor digitorum profundus (FDP) and partial FDS
division faring worse with our current mobilization
than any other combination of tendon lacerations.
Another fact that we ignore is that fingers with both
tendons cut with the finger flexed have two repair lines
that are a long way apart when the finger is extended
and only come together in flexion. By contrast, when
the finger is cut in extension, the tendon repairs remain
together all the time throughout flexion and extension.
It might reasonably be expected that the results would
differ between these two injuries. A third fact about
zone 2 that we ignore in putting all the results together
is that the sheath is not a cylinder of unchanging topog­
raphy along the length of the zone. This is equally true
of zone 1.50 So, the tendon environment is varying
quite dramatically along both zones. Unfortunately, the
circumstances in respect of analysis of zone 2 injuries
have not changed. The fact that it is difficult to collect
even 50 acute zone 2 finger flexor injuries in a single
unit makes for an ongoing problem for those research­
ing new suture configurations in this field: if only 2 or
3 in every 50 repairs rupture, then it takes a long time
before we can be sure that any innovation has achieved
anything.
THE FLEXOR POLLICIS LONGUS MODEL
The flexor pollicis longus (FPL) tendon had been
researched very little over the previous 30 years, but the
extensive literature of an earlier era (1937 to 1960)
clearly identified a much higher rupture rate after
primary repair than that of the finger flexors.51,52 Sur­
geons at that time recognized this and debated whether
to repair this tendon by insertion of a tendon graft or
by lengthening the proximal tendon.52 When we
reported our results of zone 1 and 2 finger flexors in
1994,30 we also looked at the FPL results and found a
rather horrific rupture rate of 17% in 30 thumbs when
mobilized in the Belfast regimen of active flexion/active
extension of the repairs. At that time, we recommended
that this technique of mobilization not be used in its
present form after repair of the long thumb flexor.

131
Chapter 13B:  The Chelmsford Experience
patients, the distribution of hand casualties, availability
of therapists, the training of more hand surgeons and
therapists, and so on. Regrettably, our government and
immediate administrators, in keeping with many others,
have reduced facilities for treatment of this group of
patients progressively over the past few years. Neverthe­
less, it is probably still true to say that, globally, the
number of good hand units continues to increase, with
the result that primary flexor surgery is being carried
out to higher standards in more places now than 20
years ago.
CONCLUSION
However, given that 10 of every 100 patients undergoing
surgery in a good unit will still either experience rupture
of the repair or require a tenolysis to free stuck tendons,
we should not be satisfied with current practice. While
we are still obliged to call results “excellent” when they
are only 85% of normal,37 the search for better treat­
ment should continue!
clinical results by more complex core suturing question­
able. A very interesting laboratory study from Manches­
ter may identify a further, previously unknown, factor
that is concerning.60 It showed that even a single suture
passed through a tendon significantly affected the teno­
cyte cell population of the tendon around it. The suture
foreign body caused the tenocytes to move away. So,
perhaps, we are unwittingly making tendon repair
breakdown more likely as we put in more sutures!
ECONOMIC FACTORS
It is possible that the current small but constant remnant
of repairs that rupture relates more closely to factors
such as the degree of cooperation of the individual
patient (discussed earlier) and the ability of surgical
units to maintain a continuing high quality of surgical
repair and rehabilitation. In the United Kingdom, as in
most parts of the world, the availability of a high level
of expertise to this patient group remains a medicopo­
litical battle over unit budgets, accommodation for
References
1. Verdan CE: Primary repair of flexor tendons, J Bone Joint Surg
(Am) 42:647–657, 1960.
2. Young RE, Harmon JM: Repair of tendon injuries of the hand,
Ann Surg 151:562–566, 1960.
3. Kleinert HE, Kutz JE, Ashbell T, et al: Primary repair of lacer­
ated flexor tendons in “no man’s land,” J Bone Joint Surg (Am)
49A:577, 1967.
4. Elliot D, Harris SB: The assessment of flexor tendon func­
tion after primary tendon repair, Hand Clin 19:495–503,
2003.
5. Small JO, Brennen MD, Colville J: Early active mobilisation
following flexor tendon repair in zone 2, J Hand Surg (Br)
14:383–391, 1989.
6. Becker H, Orak F, Duponselle E: Early active motion follow­
ing a bevelled technique of flexor tendon repair: Report on
fifty cases, J Hand Surg (Am) 4:454–460, 1979.
7. Brunelli G, Vigasio A, Brunelli F: Slip-knot flexor tendon
suture in zone 2 allowing immediate mobilisation, Hand
15:352–358, 1983.
8. Bunnell S: Repair of tendons in the fingers and description
of two new instruments, Surg Gynecol Obstet 126:103–110,
1918.
9. Emery FE: Immediate mobilization following flexor tendon
repair. A preliminary report, J Trauma 17:1–7, 1977.
10. Furlow LT: The role of tendon tissues in tendon healing, Plast
Reconstr Surg 57:39–49, 1976.
11. Garlock JH: The repair processes in wounds of tendons, and
in tendon grafts, Ann Surg 85:92–103, 1927.
12. Hernandez A, Velasco F, Rivas A, et al: Preliminary report on
early mobilization for the rehabilitation of flexor tendons,
Plast Reconstr Surg 40:354–358, 1967.
13. Hester TR, Hill L, Nahai F: Early mobilization of repaired
flexor tendons within digital sheath using an internal profun­
dus splint: Experimental and clinical data, Ann Plast Surg
12:187–198, 1984.
14. Harmer TW: Tendon suture, Boston Med Surg J 177:808–810,
1917.
15. Harmer TW: Cases of tendon and nerve injury, Boston Med
Surg J 194:739–747, 1926.
16. Harmer TW: Injuries to the hand, Am J Surg 42:638–658,
1938.
17. Lahey FH: A tendon suture which permits immediate motion,
Boston Med Surg J 188:851–852, 1923.
18. Lexer E: Die Verwerthung der freien Sehnentransplantation,
Archiv Klin Chir 98:818–825, 1912.
19. Kessler I, Nissim F: Primary repair without immobilisation of
flexor tendon division within the digital sheath, Acta Orthop
Scand 40:587–601, 1969.
20. Mangus DJ, Brown F, Byrnes W, et al: Tendon repairs with
nylon and a modified pullout technique, Plast Reconstr Surg
48:32–35, 1971.
21. Mantero R, Bertolotti P, Badoini C: II pull-out in “no man’s
land” e al canale digitale nelle lesioni dei flessori (metodo
personale), Riv Chir Mano 11:119–130, 1973/74.
22. Murray G: A method of tendon repair, Am J Surg 99:334–335,
1960.
23. Nigst H: Chirurgie der Beugesehnen, Handchir 8:225–236,
1976.
24. Pribaz JJ, Morrison WA, Macleod AM: Primary repair of flexor
tendons in no-man’s land using the Becker repair, J Hand Surg
(Br) 14:400–405, 1989.
25. Savage R, Risitano G: Flexor tendon repair using a “six strand”
method of repair and early active mobilisation, J Hand Surg
(Br) 14:396–399, 1989.
26. Bainbridge LC, Robertson C, Gillies D, et al: A comparison
of post-operative mobilization of flexor tendon repairs with
“passive flexion-active extension” and “controlled active
motion” techniques, J Hand Surg (Br) 19:517–521, 1994.
27. Cullen KW, Tolhurst P, Lang D, et al: Flexor tendon repair in
zone 2 followed by controlled active mobilisation, J Hand
Surg (Br) 14:392–395, 1989.
28. Elliot D, Moiemen NS, Flemming AFS, et al: The rupture rate
of acute flexor tendon repairs mobilized by the controlled
active motion regimen, J Hand Surg (Br) 19:607–612, 1994.
29. Harris SB, Harris D, Foster AJ, et al: The aetiology of acute
rupture of flexor tendon repairs in zones 1 and 2 of the fingers
during early mobilization, J Hand Surg (Br) 24:275–280,
1999.

132
Section 2:  Primary Flexor Tendon Surgery
30. Baktir A, Türk CY, Kabak S, et al: Flexor tendon repair in zone
2 followed by early active mobilization, J Hand Surg (Br)
21:624–628, 1996.
31. Lister GD, Kleinert HE, Kutz JE, et al: Primary flexor tendon
repair followed by immediate controlled mobilisation, J
Hand Surg (Am) 2:441–451, 1977.
32. Chow JA, Thomes LJ, Dovelle S, et al: A combined regimen
of controlled motion following flexor tendon repair in “no
man’s land,” Plast Reconstr Surg 79:447–455, 1987.
33. Chow JA, Thomes LJ, Dovelle S, et al: Controlled motion
rehabilitation after flexor tendon repair and grafting. A multi-
centre study, J Bone Joint Surg (Br) 70:591–595, 1988.
34. Gault DT: A review of repaired flexor tendons, J Hand Surg
(Br) 12:321–325, 1987.
35. Saldana MJ, Chow JA, Gerbino P 2nd, et al: Further experience
in rehabilitation of zone II flexor tendon repair with dynamic
traction splinting, Plast Reconstr Surg 87:543–546, 1991.
36. Duran RJ, Houser RG: Controlled passive motion following
flexor tendon repairs in zones II and III. In Hunter JM,
Schneider LH, editors: AAOS Symposium on Flexor Tendon
Surgery in the Hand, St Louis, 1975, CV Mosby, pp 105–114.
37. Strickland JW, Glogovac SV: Digital function following flexor
tendon repair in zone II: A comparison of immobilization
and controlled passive motion techniques, J Hand Surg (Am)
5:537–543, 1980.
38. Kirchmayr L: Zur Technik der Sehnennaht, Zentralbl Chir
40:906–907, 1917.
39. Amadio PC: Outcome assessment in hand surgery and hand
therapy: an update, J Hand Ther 14:63–67, 2001.
40. Jansen CW, Watson MG: Measurement of range of motion of
the finger after flexor tendon repair in zone II of the hand,
J Hand Surg (Am) 18:411–417, 1993.
41. So YC, Chow SP, Pun WK, et al: Evaluation of results in flexor
tendon surgery: A critical analysis of five methods in ninety-
five digits, J Hand Surg (Am) 15:258–264, 1990.
42. Tsuge K, Ikuta Y, Matsuishi Y: Intra-tendinous tendon suture
in the hand—a new technique, Hand 7:250–255, 1975.
43. Tsuge K, Ikuta Y, Matsuishi Y: Repair of flexor tendons by
intratendinous suture, J Hand Surg 2:436–440, 1977.
44. Silfverskiöld KL, May EJ: Flexor tendon repair in zone II with
a new suture technique and an early mobilization program
combining passive and active flexion, J Hand Surg (Am)
19:53–60, 1994.
45. Savage R: The influence of wrist position on the minimum
force required for active movement of the interphalangeal
joints, J Hand Surg (Br) 13:262–268, 1988.
46. Dowd MB, Figus A, Harris SB, et al: The results of immediate
re-repair of zone 1 and 2 primary flexor tendon repairs which
rupture, J Hand Surg (Br) 31:507–513, 2006.
47. Peck FH, Kennedy SM, Watson JS, et al: An evaluation of the
influence of practitioner-led hand clinics on rupture rates
following primary tendon repair in the hand, Br J Plast Surg
57:45–49, 2004.
48. Elliot D: Primary flexor tendon repair: operative repair,
pulley management and rehabilitation, J Hand Surg (Br)
27:507–513, 2002.
49. Tang JB: Indications, methods, postoperative motion and
outcome evaluation of primary flexor tendon repairs in Zone
2, J Hand Surg (Eur) 32:118–129, 2007.
50. Moiemen NS, Elliot D: Primary flexor tendon repairs in zone
1, J Hand Surg (Br) 25:78–84, 2000.
51. Murphy FG: Repair of laceration of flexor pollicis longus
tendon, J Bone Joint Surg (Am) 19:1121–1123, 1937.
52. Sirotakova M, Elliot D: Early active mobilization of primary
repairs of the flexor pollicis longus tendon, J Hand Surg (Br)
24:647–653, 1999.
53. Giesen T, Sirotakova M, Elliot D: Flexor pollicis longus
primary repair: further experience with the Tang technique
and controlled active mobilisation, J Hand Surg (Eur) 34:
758–761, 2009.
54. Sirotakova M, Elliot D: Early active mobilization of primary
repairs of the flexor pollicis longus tendon with two Kessler
two strand core sutures and a strengthened circumferential
suture, J Hand Surg (Br) 29:531–535, 2004.
55. Smith AM, Evans DM: Biomechanical assessment of a new
type of flexor tendon repair, J Hand Surg (Br) 26:217–219,
2001.
56. Silfverskiöld KL, Andersson CH: Two new methods of tendon
repair: an in vitro evaluation of tensile strength and gap for­
mation, J Hand Surg (Am) 18:58–65, 1993.
57. Tang JB, Shi D, Gu YQ, et al: Double and multiple looped
suture tendon repair, J Hand Surg (Br) 17:699–703, 1994.
58. Tang JB, Gu YT, Rice K, et al: Evaluation of four methods of
flexor tendon repair for postoperative active mobilisation,
Plast Reconstr Surg 107:742–749, 2001.
59. Kubota H, Aoki M, Pruitt DL, et al: Mechanical properties of
various circumferential tendon suture techniques, J Hand Surg
(Br) 21:474–480, 1996.
60. Wong JK, Cerovac S, Ferguson MW, et al: The cellular effect
of a single interrupted suture on tendon, J Hand Surg (Br)
31:358–367, 2006.

133
Robert R.L. Gray, MD, and Peter C. Amadio, MD
C
The Mayo Clinic Experience
OUTLINE
This chapter presents the indications, methods, and
postoperative care for flexor tendon repair that are
followed at the Mayo Clinic.
Flexor tendon injuries in the hand, especially in zone 2,
have proved to be a difficult clinical entity to manage,
with humbling results in many cases. Advances in repair
technique, suture material, and rehabilitation have
improved outcomes over historic controls, but the
typical result remains a finger with motion that is less
than normal.
Many basic science studies have looked at various
biomechanical aspects of tendon repair, as well as
biologic aspects of tendon healing and adhesion
formation.1-4 Manipulation of these biologic processes,
in an effort to speed healing, limit scarring, or both,
has come the fore of tendon repair research, as
biomechanical gains are providing relatively modest
clinical improvements in comparison with initial
breakthroughs.5
In our research in flexor tendon repair, we similarly
investigated methods of improving healing as well as
improving motion and lowering work of flexion. Pri­
marily, in our lab, we have focused on lowering gliding
resistance by improving repair methods and by the addi­
tion of bioactive compounds to limit scar formation
and decrease friction. The results are encouraging and
will direct future efforts by serving as benchmark and
model for comparison of new techniques.6-9
Examination of our clinical experience with flexor
tenorrhaphy reveals some emerging trends, but more
significantly, illuminates some limitations in our ability
to address these injuries. Without dedicated prospective
data collection, much of the outcome information is
not standardized. In addition, as part and parcel of
the patient population who experience these injuries,
frequently young men, not always steadily employed
and often, at our center, being referred from a great
distance for surgery, with aftercare provided closer to
home, compliance, and follow-up have been variable.
What follows is a resume of our current approach to
these problems.
INDICATIONS
Our indications for primary flexor tenorrhaphy are rela­
tively simple and inclusive. Any patient with an acute
traumatic tendon injury who desired surgery after an
explanation of the risks, benefits, and alternatives is
offered the procedure. In addition to the tendinous
injury, associated bony and neurovascular injuries are
repaired as indicated. Typically, this included primary
neurorrhaphy with or without a nerve conduit and arte­
rial repair if both proper digital arteries are injured. If
soft tissue coverage is lacking, this is addressed first,
though often recently through microsurgical techniques
that have allowed skin cover and tendon repair to be
accomplished simultaneously.
OPERATIVE TECHNIQUES
There are currently 12 hand surgeons at the Mayo Clinic.
Although there are some shared practices, each surgeon
manages his or her own patients. As time has progressed,
there has been a trend toward repair techniques with
greater numbers of core suture strands.2 Currently, for
flexor digitorum profundus (FDP) repairs in zone 2,
many surgeons use a double Tsuge repair of 3-0 Supra­
mid, with a running peripheral suture of 6-0 Prolene
(Figure 13[C]-1). Others prefer a double modified Pen­
nington repair of 3-0 or 4-0 Ticron, Supramid, or, more
recently, Fiberwire, again with a running suture of 6-0
Prolene in the epitenon (Figure 13[C]-2). Less com­
monly, some surgeons use the Strickland six-strand
technique, a Tajima modification of a Kessler two-strand
technique, or a cruciate four-strand technique.13 We find
the locking loops of the Pennington repair to be particu­
larly effective, especially when they are tightened sepa­
rately prior to tying the knot. For those who use it, the
speed of the Tsuge repair is an attraction, especially in
cases of polytrauma.
While a running simple epitendinous suture of 6-0
Prolene is most commonly used to tidy the FDP repair,
occasionally a running locked suture is used for this
purpose. In cases with transections of the FDP and both
slips of the flexor digitorum superficialis (FDS), we
seldom repair all three tendons. Most commonly, one
slip of FDS (the smaller or less easily repaired side, if
there is a difference) is excised to minimize bulk at the
repair site.10-12 When all three tendons are repaired, the
most common repair of the FDS slips is a single figure-
of-eight stitch.
In all repair techniques, efforts are made to keep any
surface knots and suture loops limited, especially on the
volar surface. If the knots and loops are not buried in
the repair site (modified Kessler), they are positioned

134
Section 2:  Primary Flexor Tendon Surgery
A
B
C
D
E
F
G
H

135
Chapter 13C:  The Mayo Clinic Experience
Figure 13(C)-1  A, Nerve cutting box is used to freshen and prepare tendon edge. B, Tendon edges are opposed without
tension. Note the repaired FDS slip beneath and the Keith needle used to prevent the proximal FDP tendon stump from
retracting. C, The lateral third of the distal stump is grasped with the first stitch. D, The stitch is locked through the looped
end. E, The next throw is begun just distal to the grasping loop, taking care to center it within the tendon. The loop should
be pulled securely flat prior to completing the repair. F, The second Tusge stitch is placed in the same fashion. One side of
the suture loop is cut at this point. G, Approximately one-third of the tendon is grasped in the next throw. The two suture
ends are now tied for each suture loop to complete the repair. H, Completion of core suture repair. Note the absence of
gapping or bunching at the repair site. An epitendeninous repair is then performed at this point with fine (6-0)
nonabsorbable monofilament suture.
A
B
C
D
E
Figure 13(C)-2  A, Proximal stump is entered for modified
Kessler repair. Note that the tendon is grasped within
the stump so that the surface is not damaged by the
forceps—a “no-touch” technique. B, A grasping stitch is
completed and a transverse stitch is placed across the
midsubstance of the tendon. C, Another grasping stitch
exiting the proximal stump completes that side. The
grasping loop on the distal stump is thrown. D, The distal
stitch is completed. The strands are tied together so that
the knots are completely within the repair site. E, The
repair is completed and a running epitendinous repair is
completed with 6-0 nylon suture.

136
Section 2:  Primary Flexor Tendon Surgery
extension with IP flexion and wrist flexion, MCP exten­
sion, and IP extension. In this protocol, which allows
passive pull both proximally and distally in zone 2,
the MCP joints are separately mobilized by alternating
this modified synergistic pattern with the normal syner­
gistic motion of wrist extension with fist alternating
with wrist flexion and finger extension. For patients who
live close to the clinic, biweekly or every-other-day
therapy visits are scheduled in the first few weeks post­
operatively. The patient is seen by the surgeon at a
minimum of once weekly. Patients who live at a dis­
tance pose more problems, because it is difficult to
supervise their rehabilitation.
SUMMARY
The experience with primary flexor tendon repair at the
Mayo Clinic is probably typical of most institutions.
These are a challenging clinical entity in isolation and
more often than not are accompanied by a neurovascu­
lar injury that further hinders the results. Repair tech­
niques have tended to increase the number of core
suture strands over time, as well as those that use a
locking stitch as opposed to a grasping stitch. Most
surgeons are now choosing a four-strand technique with
a trend toward the Tsuge being the repair of choice.
Epitendinous stitches are nearly universally used with a
6-0 nonabsorbable monofilament suture. When both
slips of the FDS and the FDP are transected in zone 2,
one slip of the FDS is often, but not always, resected to
reduce bulk at the repair site.
Flexor tendon injuries remain an important clinical
problem due to their frequency and complex manage­
ment. As repair techniques and rehabilitation protocols
have improved, increasing attention is being placed on
biologic interventions to improve healing and decrease
adhesion formation. Improvements in results will likely
be seen once these adjunctive methods leave the labora­
tory and enter the clinical sphere.
laterally (Tsuge) so that they do not interfere with
tendon gliding.14 Lateral position of the suture knots
has been shown to lower substantially the work of
flexion. Less frequently, knots of the Tsuge repair are
buried in slits made in the tendon substance.
Neurovascular injuries are quite common, occurring
in nearly two-thirds of our patients. Typically, all proper
digital nerves are repaired when feasible, but usually
isolated proper digital artery injuries are not repaired.
Mangled hands of course must be managed separately,
often with delayed repair or secondary reconstruction.
POSTOPERATIVE CARE
The postoperative protocol used nearly universally in
our historical series was the modified Duran protocol
as described in the Indiana Hand Center guide to hand
therapy.15 While this is still preferred by several in our
group, others now prefer early protected mobilization
with synergistic wrist motion flexor tendon rehabilita­
tion protocols.16 Some prefer the use of hinged dorsal
splints that, while effective, are expensive to fabricate.
Patients are usually seen for their initial visit 3 to 6
days postoperatively.17 The initial postoperative dressing
is usually a well-padded dorsal splint with the wrist in
30° of flexion and the metacarpophalangeal (MCP)
joints in flexion, with the interphalangeal (IP) joints
blocked at 0°extension. Using IP motion is allowed in
this splint, although some prefer full immobilization
for the first few days postoperatively. This initial dress­
ing is removed at the first postoperative visit, and the
wounds are examined. A protective dorsal-blocking
thermoplastic splint is then usually fabricated. Depend­
ing on the level of swelling present in the digits, the
standard Duran passive motion protocol is initiated at
this point or, if swelling is minimal, place-and-hold
exercises are begun immediately.18 Several surgeons
now use the modified Tanaka method, in which the
synergistic motion includes alternating wrist and MCP
References
1. Momose T, Amadio PC, Zhao C, et al: The effect of knot loca­
tion, suture material, and suture size on the gliding resistance
of flexor tendons, J Biomed Mater Res 53:806–811, 2000.
2. Momose T, Amadio PC, Zhao C, et al: Suture techniques
with high breaking strength and low gliding resistance: exper­
iments in the dog flexor digitorum profundus tendon, Acta
Orthop Scand 72:635–641, 2001.
3. Yang C, Zhao C, Amadio PC, et al: Total and intrasynovial
work of flexion of human cadaver flexor digitorum profundus
tendons after modified Kessler and MGH repair techniques,
J Hand Surg (Am) 30:466–470, 2005.
4. Tanaka T, Amadio PC, Zhao C, et al: Gliding characteristics
and gap formation for locking and grasping tendon repairs:
A biomechanical study in a human cadaver model, J Hand
Surg (Am) 29:6–14, 2004.
5. Zhao C, Sun YL, Ikeda J, et al: Improvement of flexor tendon
reconstruction with carbodiimide-derivatized hyaluronic acid
and gelatin-modified intrasynovial allografts: study of a
primary repair failure model, J Bone Joint Surg (Am) 92:2817–
2828, 2010.
6. Akasaka T, Nishida J, Araki S, et al: Hyaluronic acid dimin­
ishes the resistance to excursion after flexor tendon repair: An
in vitro biomechanical study, J Biomech 38:503–507, 2005.
7. Sun Y, Chen MY, Zhao C, et al: The effect of hyaluronidase,
phospholipase, lipid solvent and trypsin on the lubrication
of canine flexor digitorum profundus tendon, J Orthop Res
26:1225–1229, 2008.
8. Zhao C, Sun YL, Kirk RL, et al: Effects of a lubricin-containing
compound on the results of flexor tendon repair in a canine
model in vivo, J Bone Joint Surg (Am) 92:1453–1461, 2010.
9. Yoshii Y, Villarraga HR, Henderson J, et al: Speckle tracking
ultrasound for assessment of the relative motion of flexor
tendon and subsynovial connective tissue in the human
carpal tunnel, Ultrasound Med Biol, 35:1973–1981, 2009.