Operative Technique in Plastic Surgery – Kevin C.Chung

TECH FIG 1 • Single-stage flexor tendon
reconstruction. A. Bruner incisions in the digit and
palm. If needed, a forearm incision is marked for more
proximal rod placement. B,C. The proximal tendon is
excised. D. The tendon sheath is intact. E,F. The
tendon graft is passed through the distal phalanx and
tied over a button. G. The tendon suture is weaved to
the profundus tendon proximally with fingers in slight
flexion. H. Completed single-stage tendon

reconstruction.
■ The lumbrical may be released if it is scarred.
■ At this point, a moist gauze is placed over the wound, and the graft is
harvested.
■ The harvested graft may be first secured to the distal or proximal junction
first, but we prefer to secure it first distally to facilitate setting tension.
■ The graft is sutured. We prefer a smooth 2.0 Prolene or a 4.0 steel wire in a
horizontal mattress configuration to facilitate easy pullout.
■ The sutures are shuttled through the tendon sheath by using a tendon passer
(TECH FIG 1D). The ends of the suture are brought distally and can be used
to slide the tendon graft through the sheath.
■ The distal end of the graft is woven once through the FDP stump with the
tendon weaver (TECH FIG 1E,F).
■ A Keith needle is placed into a wire driver and drill across the base of the
distal phalanx.
■ One suture end is threaded through the eyelet and passed dorsally through
the nail plate either through or around the bone, taking care not to pierce the
germinal matrix. The other suture is passed the same way.
■ The sutures may be tied over a polypropylene button or over the nail plate.
■ Alternatively, the graft can be secured with a small suture anchor in the
distal phalanx; the anchor is placed in the FDP insertion and angled slightly
proximally with care to avoid intra-articular penetration of the DIP joint.
■ The graft is then sutured to the distal FDP stump at the distal weave.
■ The wrist is positioned in neutral, and the graft is tensioned to place the
finger in slight flexion and aligned with the natural cascade (TECH FIG
1G). Err on the side of overtensioning rather than undertensioning.
■ The proximal end of the graft is then weaved through the proximal FDP
tendon at the correct tension (TECH FIG 1H).
■ We prefer three weaves, each 90 degrees to each other, which are secured
with figure-of-8 sutures.
■ Two-Stage Flexor Tendon Reconstruction
Stage 1

■ Approach the finger with a volar Bruner incision (TECH FIG 2A).
■ Assess the flexor sheath and preserve as much as possible.
■ If the sheath is deficient, pulley reconstruction is indicated.
■ A lacerated sheath may be repaired in this stage as long as it does not hinder
the gliding of the rod.
■ A stenotic sheath may require dilatation or partial release in order to pass the
rod.
■ Cut the FDS and FDP leaving a 1- to 2-cm stump at the insertion sites. The
excised tendon can be used for pulley reconstruction and should be
maintained on the field during the case.
■ There are two approaches to rod placement, depending on the anticipated
location of the tenorrhaphy. Some surgeons perform the tenorrhaphy in the
palm, whereas others perform the tenorrhaphy at the level of the forearm.
■ If there is a large amount of scarring in the palm, forearm placement is
preferred.
■ If a forearm tenorrhaphy is used, a palmaris longus tendon is usually too
short and a plantaris tendon or other longer tendon may be needed at the
secondary reconstruction.
■ An incision can be made in the palm or in the distal forearm.
■ Identify the FDS and FDP tendons by using a turn-key motion with an Allis
clamp. This is performed by clamping around the tendon and then twisting
the clamp so the tendon wraps around the tines. This allows the surgeon to
apply a force in line with the tendon and helps avoid pulley rupture.
■ The FDS is released and allowed to retract proximally in most cases, but
may be retained as the motor for the second stage if the FDP is of poor
quality.
■ Shorten the FDP but tag it with a suture and sew it side to side to an adjacent
FDP tendon to prevent retraction and allow easy identification in stage 2.
■ Suture the silicone rod into the distal FDP stump. The size of the rod should
fit snugly into the sheath. It is usually 4 to 6 mm.
■ Guide the rod through the flexor sheath (TECH FIG 2B–D) and allow it to
float freely through the carpal tunnel and into the forearm.
■ You should observe the rod in the proximal forearm incision, and it should
glide smoothly without buckling as the finger is taken through a range of
motion.
■ Alternatively, the silicone rod can be loosely tacked to the FDP at the level

of the palm if it has not retracted proximally.
■ Over the course of 2 or 3 months, the gliding silicone rod creates a
lubricated pseudosheath.1
Stage 2
■ Use the previous incisions to identify the silicone rod proximally and
distally.
■ Obtain the tendon graft. Be sure the length of the graft will be sufficient to
span the length of the defect (TECH FIG 3A,B).
TECH FIG 2 • Stage 1 of two-stage flexor tendon
reconstruction. A. Volar Bruner incision in the finger
and palm. B. The Hunter rod placement in flexor
sheath. C. Hunter rod sutured to the FDP stump. D.
Completed stage 1 of two-stage tendon
reconstruction.
■ Identify the rod distally in the finger.
■ Cut the sutures between the rod and the FDP stump and suture the distal end
of the rod to the proximal end of the graft (TECH FIG 3C).
■ Pull the rod through the proximal incision, which will shuttle the graft

through the sheath.
■ Perform a tendon weave on the distal FDP stump as described above for
single-stage grafting. If no stump is present, the graft can be inserted into the
distal phalanx with transosseous sutures tied over a button or the nail plate or
with a suture anchor (TECH FIG 3D).
■ Estimate the tension of the graft to produce slight flexion aligned with the
natural cascade (TECH FIG 3E).
■ Err on the side of overtensioning rather than undertensioning.
■ Perform a Pulvertaft weave on the proximal FDP using three orthogonal
weaves (TECH FIG 3F).
■ If the proximal FDP stump cannot be identified, a tenodesis to the adjacent
FDP tendon can be performed.

TECH FIG 3 • Stage 2. A,B. The tendon graft is
harvested. C. The sutures are cut between the rod
and the FDP stump, and the distal end of the rod is
sutured to the proximal end of the graft. D. A tendon
weave is performed on the distal FDP stump. E. The
tension of the graft is estimated to produce slight
flexion aligned with the natural cascade. F. Completed
stage 2 of two-stage tendon reconstruction.
■ Paneva-Holevich Modification
■ Described in 1969, this modification obviates the need for tendon graft
harvest in stage 2.2
■ In stage 1, the volar finger is approached and the silicone rod is secured to
the distal FDP or the distal phalanx as described above.
■ The FDS and FDP tendons are both identified in the palm and transected at
the level of the lumbrical origin proximal to the A1 pulley. Both distal ends
are sutured to each other using a locking core suture technique. We prefer a
Kessler stitch with a running epitendinous stitch.
■ The FDP-FDS “loop” will heal over 3 months.
■ In stage 2, the finger is exposed again.

■ The FDS tendon is transected as far proximal as possible. Pull the FDS-
FDP loop out of the palm. The proximally cut FDS tendon now becomes
the distal end of the graft.
■ Suture the distal end of the tendon graft to the silicone rod and shuttle the
graft through the pseudosheath.
■ Tension the graft and secure it as described above.
■ Pulley Reconstruction
■ Pulley reconstruction is performed at the first stage of the tendon
reconstruction if the A2 and A4 pulleys are deficient (TECH FIG 4A).
■ We prefer the tendon-wrapping method described by Bunnell.3
■ Approximately 12 cm of graft may be required to encircle the phalanx twice.
Oftentimes this can be obtained from excised flexor tendon.
■ The A2 and A4 pulleys should be reconstructed.
■ At the level of the proximal phalanx, the graft lies deep to the extensor
mechanism and deep to the neurovascular bundle, so that the intrinsic
tendons and the finger vascularity are not disrupted.
■ Whipstitch one end of the graft with a 4.0 braided suture.
■ Use a curved hemostat to dissect around the proximal phalanx deep to the
extensor mechanism, and pass the suture into the clamp.
■ Pass the graft around the mid shaft of the proximal phalanx twice and suture
to itself using 3.0 nonabsorbable suture.
■ At the level of the middle phalanx, the graft is passed superficial to the
extensor mechanism but still deep to the neurovascular bundle. Encircle the
middle phalanx twice and suture the graft to itself (TECH FIG 4B–D).
■ An alternative method is to shoestring the graft through existing pulley
edges. The residual pulley is often stiff enough to support the weave.

TECH FIG 4 • Pulley reconstruction using tendon
autograft. A. A2 and A4 pulley location. B. The grafts
are looped twice around the proximal phalanx. C,D.
The graft is passed under the extensor mechanism for
the A2 reconstruction and over the extensor
mechanism for the A4 reconstruction.
PEARLS AND PITFALLS
Indications
■ Single-stage grafting is indicated for a segmental gap in the tendon
with an intact sheath.
■ Two-stage grafting is indicated for a segmental tendon gap with
excessive scarring, multistructure injury, failed tendon zone II
repair, and/or a deficient sheath.
■ Digits considered for reconstruction should have adequate

vascularity and protective sensation.
■ Alternatives to tendon reconstruction include adjacent FDS to FDP
tendon transfer, arthrodesis, and amputation.
Graft
planning
■ Be sure the desired graft is anatomically present.
■ Plan for a graft with sufficient length.
■ If the graft needs to reach the palm, a palmaris graft may be
sufficient.
■ If the graft needs to reach the forearm, a plantaris graft may be
necessary.
■ If a graft is not present, an allograft gracilis or semitendinosus is an
acceptable alternative.
■ The graft should be about 4–5 mm in width to pass through the
sheath easily.
Preservation
of intact
structures
■ Do not sacrifice an intact FDS to pass a tendon graft.
■ Preserve as much of the native sheath as possible—not just A2 and
A4.
POSTOPERATIVE CARE
Stage 1
■ The major goal of stage 1 is to maintain passive range of motion
■ 0 to 2 weeks: edema control, dorsal thermoplast splint (wrist neutral, MP joint
60 degrees of flexion, IP joints 0 degrees). Passive flexion and active/passive
extension for all joints 6 times per day. If a pulley reconstruction was
performed, a thermoplast circumferential pulley ring is worn for 6 weeks.
■ 2 to 6 weeks: Remove splint. Buddy strap affected finger to adjacent finger.
Continue active and passive exercises until stage 2 is performed
(approximately 12 weeks).
Stage 2 (Modified Duran)
■ 0 to 3 weeks: Edema control, dorsal thermoplast splint (wrist 20 degrees of
flexion, MP joint 60 degrees of flexion, IP joints 0 degrees). Passive flexion
and active/passive extension for all joints 6 times per day.
■ 3 to 4 weeks: Add active range of motion (AROM), tendon gliding, and place
hold exercises in the splint.
■ 4 to 6 weeks: Exercises can be performed out of splint. Add blocking exercises
to PIP and DIP. Add wrist tenodesis exercises. Add grasp, dexterity, and ADL

exercises.
■ 6 to 8 weeks: Splint is only worn at night and in crowds. Volar pancake or IP
joint extension splints may be added if necessary. Add light resistance
exercises.
■ 8 to 12 weeks: Discontinue splint. Add progressive resistance exercises and
work simulation activities.
OUTCOMES
■ Outcomes results are graded by a variety of measures including total active arc
of motion (TAM), grip and pinch strength, and scoring systems by Schneider,
Stark, and Strickland.4–6
■ In general, results of primary repair are superior to reconstruction, and fingers
with an intact FDS obtain better motion than do those without one.7 Other
factors that portend a better prognosis are younger patient, less soft tissue scar,
good preoperative mobility, and at least one intact sensory nerve.8
■ Grafting through an intact FDS, Stark et al. reported “satisfactory” finger
flexion in 20 of 25 patients, defined as a distance of the pulp to distal flexion
crease within 3.2 cm and 20-degree active DIP flexion.5 Using similar criteria,
McClinton et al. reported success in 87 of 100 patients with an average of 48
degrees of DIP flexion.9
■ Two-stage grafting reported by Hunter and Salisbury resulted in pulp to crease
flexion within 3.2 cm in 85% of the 69 cases.10
■ TAM for two-stage grafting ranges from 186 to 206 degrees.7,11,12
COMPLICATIONS
■ Adhesion of the graft is the most common complication. A tenolysis may be
required 3 to 6 months after stage 2 reconstruction.
■ Bowstringing, tendon rupture, and infection are also not uncommon
complications.
■ A tight FDP graft may cause the “quadriga effect,” whereby the adjacent digits
experience a flexor lag as described earlier.
■ A loose FDP graft may cause imbalance in the finger. A swan-neck deformity
or a lumbrical plus finger may be the result. Lumbrical plus finger is diagnosed
when “paradoxical extension” of the IP joints occurs when the patient attempts
to make a fist; the lumbrical originates on the FDP and pulls the IP joints into
extension when a retracted FDP contracts. Retensioning the graft or resection
of the lumbrical origin may be required.

REFERENCES
1. Hunter JM, Subin D, Minkow F, Konikoff J. Sheath formation in response to
limited active gliding implants (animals). J Biomed Mater Res. 1974;5:155.
2. Paneva-Holevich E. Two-stage tenoplasty in injury of the flexor tendons of
the hand. J Bone Joint Surg. 1969;51(1):21-32.
3. Bunnell S. Repair of tendons in the fingers and description of two new
instruments. Surg Gynecol Obstet. 1918;26:103-110.
4. Schneider LH. Staged flexor tendon reconstruction using the method of
Hunter. Clin Orthop Relat Res. 1982;171:164-171.
5. Stark HH, Zemel NP, Boyes JH, Ashworth CR. Flexor tendon graft through
intact superficialis tendon. J Hand Surg [Am]. 1977;2(6):456-461.
6. Leversedge FJ, Zelouf D, Williams C, et al. Flexor tendon grafting to the
hand: an assessment of the intrasynovial donor tendon: a preliminary single-
cohort study. J Hand Surg [Am]. 2000;25(4):721-730.
7. Tonkin M, Hagberg L, Lister G, Kutz J. Post-operative management of flexor
tendon grafting. J Hand Surg [Br]. 1988;13(3):277-281.
8. Boyes JH, Stark HH. Flexor-tendon grafts in the fingers and thumb: a study of
factors influencing results in 1000 cases. J Bone Joint Surg Am.
1971;53(7):1332-1342.
9. McClinton MA, Curtis RM, Wilgis EF. One hundred tendon grafts for isolated
flexor digitorum profundus injuries. J Hand Surg [Am]. 1982;7(3):224-229.
10. Hunter JM, Salisbury RE. Flexor-tendon reconstruction in severely damaged
hands: a two-stage procedure using a silicone-Dacron reinforced gliding
prosthesis prior to tendon grafting. J Bone Joint Surg Am. 1971;53(5):829-858.
11. Beris AE, Darlis NA, Korompilias AV, et al. Two-stage flexor tendon
reconstruction in zone II using a silicone rod and a pedicled intrasynovial graft.
J Hand Surg [Am]. 2003;28(4):652-660.
12. Coyle MP Jr, Leddy TP, Leddy JP. Staged flexor tendon reconstruction
fingertip to palm. J Hand Surg [Am]. 2002;27(4):581-585.

40
CHAPTERTenolysis of Flexor Tendons
Richard Tosti, Jacques A. Machol IV, and Neal Chen
DEFINITION
■ Total active arc of motion in the fingers is approximately 260 degrees, which
is the sum of each individual joint: metacarpophalangeal (MP) joint 85 degrees,
proximal interphalangeal (PIP) 110 degrees, and distal interphalangeal (DIP)
65 degrees.
■ Flexion contracture is a loss of passive extension. Extension contracture is a
loss of passive flexion.
■ Flexion lag is a loss of active flexion, but preserved passive flexion. Extension
lag is a loss of active extension, but preserved passive extension.
■ This chapter will primarily focus on loss of digital motion caused by adhesions
of the flexor tendon.
ANATOMY
■ The strength and versatility of the hand is dependent upon the balance and
gliding of the long flexors and extensors and the intrinsic muscles.
■ The extensor apparatus is composed of four lumbrical muscles, four dorsal
interossei, three volar interossei, four extensor digitorum communis (EDC)
tendons, the extensor indicis proprius (EIP), and the extensor digiti quinti
(EDQ).
■ The long extensors (EDC, EIP, EDQ) originate in the forearm and insert on the
base of their respective proximal phalanx via the sagittal band attachments to
the volar plate. The long extensors continue distally to insert on the base of the
middle phalanx as the central slip but also give two “lateral slips” that join the
intrinsic tendons to form the lateral bands, which insert on the base of the distal
phalanx as the terminal tendon.

■ The intrinsic muscles originate in the hand and insert on the extensor
apparatus. The transverse fibers of the extensor hood link the intrinsic tendon
and the proximal phalanx. The oblique fibers of the extensor hood link the
intrinsic tendon and the middle phalanx. The tendons of the intrinsic muscles
join the lateral slips of the long extensor to form the lateral bands, which insert
as the terminal tendon.
■ Important to note is the course of the intrinsic tendon relative to centers of
rotation at the finger joints. At the MP joint, they course volar to the axis of
rotation producing a flexion moment. At the PIP and DIP joints, they course
dorsal to the axis of rotation producing an extension moment.1
■ Nine flexor tendons originate in the forearm. Flexor pollicis longus inserts at
the base of the distal phalanx of the thumb. Four flexor digitorum superficialis
(FDS) and four flexor digitorum profundus (FDP) tendons insert on the volar
base of the middle and distal phalanges, respectively.
■ The FDS tendons are superficial to the FDP in the hand, but as they enter the
fibrous sheath, the FDS bifurcates into two slips, which are directed dorsally to
their insertion.
PATHOGENESIS
■ Traumatic or postsurgical stiffness usually begins with edema or hematoma.2
■ The fluid distends the joints and surrounding structures, becoming a physical
barrier to motion.
■ The cellular response to injury initiates the inflammatory cascade.
■ The inflammatory cascade leads to fibroblast accumulation and fibroblast
proliferation into myofibroblasts.
■ Reaction to foreign material such as metal plates stimulates adhesion
formation as well.
■ Persistent motion loss leads to soft tissue contracture.
NATURAL HISTORY
■ Contracture or adhesions of dorsal structures generally limit passive flexion.
These structures include the dorsal skin, extensor tendons, intrinsic tendons,
dorsal capsule, and collateral ligaments.
■ Contracture or adhesions of the flexor tendons generally limit active flexion.
■ Contracture or adhesions of the volar structures limit passive extension. These
structures include the volar skin, flexor tendons, and volar capsule.
■ Contracture or adhesions of the extensor tendons limit active extension.

PATIENT HISTORY AND PHYSICAL FINDINGS
■ The most common stiff posturing is MP joint extension and IP joint flexion.
The MP joint is a cam shape, which holds the greatest fluid volume when in
extension. Extension at the MP creates a relative tension on the flexor tendons
that brings the IP joints into flexion.
■ However, a variety of postures and motion limitations are seen (Table 1).
Table 1 Assessment of a Stiff Finger
Cause
Active
Extension
Passive
Extension
Active
Flexion
Passive
Flexion
Extensor tendon
adhesion
−
+
−
+/−
Dorsal skin or
capsular contracture
+
+
−
−
Flexor tendon
adhesion
−
+/−
−
+
Volar skin or
capsular contracture
−
−
+
+
Dorsal and volar
combineda
−
−
−
−
Intrinsic contractureb
+
+
−
−
aCombined pathology of dorsal and volar structures by adhesion and/or
contracture.
bTesting of PIP joint with the MP joint extended.
■ Begin with assessment of passive and active range of motion (AROM).
■ Passive motion greater than active motion suggests a barrier outside the joint
(adhesion, rupture, denervation).
■ Passive motion of the PIP joint that varies with the position of the MP joint
suggests a barrier outside the joint (intrinsic or extrinsic tightness).
■ Passive motion barriers may occur from pathology either within the joint or
outside the joint.
■ Passive motion barriers mask active motion (ability or disability); thus active
joint motion can only be assessed after correction of passive motion barrier.

IMAGING
■ Stiffness is usually diagnosed by history and physical exam.
■ Radiographs may be helpful to rule out bone or joint malalignment as a cause.
DIFFERENTIAL DIAGNOSIS
■ Tendon rupture
■ Joint contracture
NONOPERATIVE MANAGEMENT
■ Prior to any attempt at tenolysis, tissue homeostasis must be achieved. This
includes a stable, supple soft tissue envelope, durable bony stability, and edema
control.
■ It is preferable to gain passive range of motion before a tenolysis procedure if
possible.
■ Daytime dynamic splints and nighttime static splints can help regain motion.
Dynamic splints are typically not worn at night, as they may lose their position.
■ Progressive static splints or serial casting can also be successful.
SURGICAL MANAGEMENT
■ Surgery may be considered for disability resulting from stiffness if 6 months
of nonsurgical management has failed to resolve symptoms.
Preoperative Planning
■ Wide-awake surgery under local anesthesia has the advantage of assessing
gains in active motion so that intraoperative modifications can be made.
■ Hardware removal may be required but should only be performed after bony
union has occurred.
■ A flexion contracture may be caused by any combination of volar skin
contracture, flexor tendon adhesion, or volar capsular contracture; these
structures can be addressed by Z-plasty lengthening, flexor tenolysis, or joint
release, respectively. Only after the flexion contracture is released can the
integrity of the extensor mechanism be assessed.3
■ An extension contracture may be caused by dorsal skin contracture, extensor
tendon adhesion, or dorsal capsule; these structures can be addressed by Z-
plasty lengthening, extensor tenolysis, or dorsal capsulotomy/collateral
ligament release, respectively. Only after the extension contracture is released
can the integrity of the flexor tendons be assessed.3

■ A flexion lag is often caused by adhesions between the flexor tendon and
surrounding bone, soft tissue, and skin. It may only be discovered after release
of an extension contracture.
■ An extension lag is often caused by adhesions between the extensor tendon
and surrounding bone, soft tissue, and skin. It may only be discovered after
release of a flexion contracture.
Positioning
■ Position the patient supine with the arm on a hand table.
■ A nonsterile tourniquet may be used proximally.
Approach
■ Dorsal approach to the finger for extensor tenolysis is made through either a
longitudinal incision centered over the PIP joint or a radially based curvilinear
incision.
■ For flexor tenolysis, a volar Bruner incision is the most common approach,
although a longitudinal midaxial incision can be considered.
■ In patients with a skin contracture, Z-plasty is often helpful.
T E C H N I Q U E S
■ Extensor Tenolysis With or Without Dorsal
Capsular Release
■ The extensor mechanism is exposed, and any adhesions to the skin are
released.
■ A Freer elevator can be used to free the extensor hood from the proximal
phalanx. This is usually performed from proximally to distally or from
laterally to centrally under the lateral bands.
■ Caution is taken to avoid detaching the central slip.
■ Adhesions to the middle phalanx can also be released from under the lateral
bands/extensor hood.
■ If there is a PIP joint contracture present, the collateral ligaments can be
excised from underneath the lateral bands.
■ Adhesions at the level of the metacarpal are approached in a similar manner

(TECH FIG 1).
■ Hardware, if present, should be removed at the time of tenolysis.
TECH FIG 1 • Extensor tendon adhesions after
fixation of metacarpal fracture, dorsal approach
showing adhesions of the extensor tendon to the skin
and underlying plate.
■ Flexor Tenolysis With or Without Volar Capsular
Release
■ Open the wound using the prior incisions and identify the neurovascular
structures first to protect them (TECH FIG 2A).
■ The A1 pulley is released and a window is opened over the cruciate and A3
pulleys.
■ The A2 and A4 pulleys are preserved as much as possible. If necessary,
pulleys may be partially “vented” by making a longitudinal incision along the
radial or ulnar border of the sheath.
■ The superficialis tendon and the profundus tendon are examined at the level
of the A1 pulley using an Allis clamp “turnkey” maneuver (TECH FIG 2B).
■ Tenolysis knives or a Freer elevator can be used to free adhesions around the

tendon. There are often deep adhesions to the bone and between the FDS and
FDP (TECH FIG 2C–G).
■ If a PIP joint contracture exists, the volar plate can be transversely incised
and the checkrein ligaments released.4
■ Rarely, FDS may be sacrificed if dense adhesions and a tight sheath are
encountered.
■ If contracture of the skin is causing the motion limitation, then preoperative
planning should include the design of a longitudinal incision with Z-
lengthening at the flexion creases.

TECH FIG 2 • A. Limited flexor tenolysis for adhesions
after a pinning of a proximal phalanx fracture. B.
Turnkey motion demonstrating return of extension. C.
Both the FDS and FDP tendons were isolated. The A4
pulley was previously excised during the initial repair
and was not competent. D–G. Tenolysis through
traction with an Allis clamp was sufficient to disrupt the
adhesions and restore motion.
■ Intrinsic Release
■ There are two types of intrinsic release:
■ The intrinsics can be released at the extensor hood.
■ The intrinsics can be released proximally off of the metacarpal in the
intrinsic slide procedure, typically for intrinsic contracture resulting from
compartment syndrome.
■ Distal release is indicated for a positive Bunnell intrinsic tightness test. The
PIP joint will have less flexion when the MP joint is extended and more
flexion when the MP joint is flexed.
■ The extensor hood is approached through a single midline dorsal incision or
a double midaxial incision.

■ The oblique fibers are identified in the distal third of the proximal phalanx.
■ A triangular wedge of the oblique fibers is excised.
■ Avoid cutting into the transverse fibers, which attach the proximal phalanx
to flex the MP joint.
■ Proximal release is indicated in patients with severe intrinsic tightness,
where the MP joint is also affected.1
■ Proximal release consists of cutting the intrinsics proximal to the MP joint.
Another alternative is an intrinsic slide where the intrinsics are released from
the metacarpal. These procedures are typically performed in more severe
intrinsic contractures such as those secondary to compartment syndrome.
PEARLS AND PITFALLS
Indications
■ Tenolysis will not improve a stiff finger that has joint incongruity
or malalignment.
■ Wounds, swelling, and inflammation should be resolved before
surgery.
■ Nonoperative measures should be continued as long as progress is
being made.
■ The patient must agree to a strict post-op rehab program before
surgery is considered.
Incision
■ For multiple MP joint extension contractures, avoid a single
transverse incision, as this will gap during early rehab.
■ Anticipate soft tissue contractures and be prepared to perform Z-
plasty or advancement flaps for coverage.
Sequential
release
■ Begin with releasing the tendon adhesions from the bone and skin.
■ Release the capsule and then ligaments if necessary.
■ Be mindful that intrinsic tightness may coexist and warrant
release.
Rehabilitation
■ Begin rehab immediately after surgery.
POSTOPERATIVE CARE
■ All protocols should begin 24 to 48 hours after surgery.
■ The quality of the tendon should be noted intraoperatively.

■ Thin, frayed, and poorly vascular tendons are at risk for rupture with an
aggressive protocol.5
Flexor Tendon Rehabilitation
■ Good-quality tendon
■ 0 to 2 weeks: Edema control, volar thermoplast splint (wrist neutral, MP and
IP joints 0 degrees) to be worn at night and in between exercises. AROM,
tendon gliding, and place-hold exercises to be performed hourly with 10 reps
each
■ 2 to 4 weeks: Continue above. Add blocking exercises to PIP and DIP. Add
grasp, dexterity, and ADL exercises. Add scar management.
■ 4 to 8 weeks: Continue above. Add sustained gripping and progressive
resistance. May add dynamic extension splint if needed.
■ 8 to 12 weeks: Add heavy resistance exercises and work simulation
activities.
■ Poor-quality tendon
■ 0 to 2 weeks: Edema control, volar thermoplast splint to be worn at night and
in between exercises. The splint is fabricated to place the joints in full
extension for extensor lag and in resting position for extension contracture.
Passive flexion performed hourly.
■ 2 to 4 weeks: Add AROM, tendon gliding, and place-hold exercises to be
performed hourly with 10 reps each. The splint is gradually brought to allow
MP joint at 0 degrees by 4 weeks. Add scar management.
■ 4 to 8 weeks: Add blocking exercises to PIP and DIP. Add grasp, dexterity,
and ADL exercises.
■ 8 to 12 weeks: Add sustained gripping and progressive resistance. May add
dynamic extension splint if needed.
■ 12 weeks: Add heavy resistance exercises and work simulation activities.
Extensor Tendon Rehabilitation
■ Good-quality tendon
■ 0 to 2 weeks: Edema control, volar thermoplast splint to be worn at night and
in between exercises. Fabricate the splint to place the finger joints in
extension for extensor lag and in resting position for extension contracture.
AROM, gliding, place-hold, and blocking exercises performed hourly.
■ 2 to 4 weeks: Add grasp, dexterity, and ADL exercises. Add scar
management.

■ 4 to 8 weeks: Add sustained gripping exercises. At 6 weeks, add progressive
resistance. May add dynamic flexion splint if needed.
■ 8 to 12 weeks: Add heavy resistance exercises and work simulation
activities.
■ Poor-quality tendon
■ 0 to 2 weeks: Edema control, volar thermoplast splint to be worn at night and
in between exercises. Fabricate the splint to place the finger joints in
extension for extensor lag and in resting position for extension contracture.
Tenodesis exercise, gentle AROM, gliding, and place-hold performed hourly.
■ 2 to 4 weeks: Add AROM and blocking exercises. Add scar management.
■ 4 to 8 weeks: Add grasp, dexterity, and ADL exercises.
■ 8 to 12 weeks: Add sustained gripping exercises and progressive resistance.
May add dynamic flexion splint if needed.
■ 12 weeks: Add heavy resistance exercises and work simulation activities.
OUTCOMES
■ Weeks et al. evaluated 789 stiff MP and PIP joints in 212 patients at a mean
3.4 months after injury. Exercises and dynamic splinting alone were effective
in 87% of patients. MP joint range of motion (ROM) improved 32 degrees on
average, while PIP joint ROM improved 36 degrees on average. Surgery was
required for the remaining 13%.6
■ Hunter et al. reported on 61 digits with PIP joint contractures treated
nonoperatively with exercises and static or dynamic splints. Preoperative
motion at the PIP joint range of motion was 24 to 67 degrees, which improved
to 8 to 98 degrees.5
■ Breton et al. reported on 75 digits that underwent postinjury zone II flexor
tendon tenolysis. They noted a preoperative total arc of motion of 128 degrees
and a postoperative arc of 192 degrees at 3 months. Flexor tendon rupture
occurred in seven cases.7
■ Yamazaki et al. noted that the preoperative range of motion was the strongest
predictor of postoperative range of motion in patients undergoing flexor
tenolysis after phalangeal fracture.8
■ Adjunctive treatments such as indwelling local anesthesia catheters and
continuous passive motion (CPM) devices have been described; however,
limited evidence justifies their routine use. Schwartz and Chafetz noted no
difference in gains in total arc of motion with CPM.9

COMPLICATIONS
■ Tendon rupture can occur if tenolysis performed before repair site is healed.
■ Tendon disruption can occur if the tenolysis erroneously strips the insertion
site.
■ Recurrence can occur if the patient is not compliant with rehab or if the zone
of injury is too great.
REFERENCES
1. Smith RJ. Balance and kinetics of the fingers under normal and pathological
conditions. Clin Orthop Relat Res. 1974;104:92-111.
2. Schneider LH. Tenolysis and capsulectomy after hand fractures. Clin Orthop
Relat Res. 1996;(327):72-78.
3. Jupiter JB, Goldfarb CA, Nagy L, Boyer MI. Posttraumatic reconstruction in
the hand. Instr Course Lect. 2007;56:91-99.
4. Watson HK, Light TR, Johnson TR. Checkrein resection for flexion
contracture of the middle joint. J Hand Surg [Am]. 1979;4:67-71.
5. Hunter E, Laverty J, Pollack R. Nonoperative treatment of fixed flexion
deformity of the proximal interphalangeal joint. J Hand Surg Br. 1999;24:281-
283.
6. Weeks PM, Wray RC Jr, Kuxhaus M. The results of non-operative
management of stiff joints in the hand. Plast Reconstr Surg. 1978;61:58-63.
7. Breton A, Jager T, Dap F, Dautel G. Effectiveness of flexor tenolysis in zone
II: a retrospective series of 40 patients at 3 months postoperatively. Chir Main.
2015;34(3):126-133.
8. Yamazaki H, Kato H, Uchiyama S, et al. Results of tenolysis for flexor tendon
adhesion after phalangeal fracture. J Hand Surg Eur Vol. 2008;33(5):557-560.
9. Schwartz DA, Chafetz R. Continuous passive motion after tenolysis in hand
therapy patients: a retrospective study. J Hand Ther. 2008;21(3):261-266.

41
CHAPTER
Acute Repair of Extensor
Tendon Injuries in Zones I to
VI
Michael Smith, Jacques A. Machol IV, and Neal Chen
DEFINITION
■ The extensor apparatus of the hand is a delicate and complex system that
works in synergy with the flexor system to facilitate gross and fine motor
activity of the hand and digits.
■ Extrinsic extensor function is provided to the digits by the extensor digitorum
communis (EDC), extensor indicis proprius (EIP), and extensor digiti minimi
(EDM). These muscles work in concert with the intrinsic muscles of the hand
to provide extension of the proximal and distal interphalangeal (DIP) joints
through the intrinsics’ contributions to the extensor mechanism via the lateral
bands.
■ The extensor apparatus can be injured by blunt or sharp trauma, as well as by
attrition from inflammatory conditions.
ANATOMY
■ The extensor tendons can be divided into superficial and deep muscle groups.1
■ The superficial group includes the extensor carpi radialis longus (ECRL), the
extensor carpi radialis brevis (ECRB), the EDC, the EDM, and the extensor
carpi ulnaris (ECU).
■ The deep group includes the extensor pollicis brevis (EPB), the extensor
pollicis longus (EPL), and the EIP.
■ The extensors are innervated by the posterior interosseous nerve (PIN) with
the exception of the ECRB and ECRL, which are innervated by the radial
nerve prior to the split into the PIN and the superficial radial nerve.2
■ The ECRB may sometimes be innervated by the PIN after the radial nerve has

split.
■ The extensor tendons travel through six separate dorsal compartments at the
level of the wrist prior to entering the hand.
■ The first dorsal compartment contains the abductor pollicis longus (APL) and
the EPB tendons.
■ There is septation of this compartment in 20% to 60% of individuals, and it is
common for the APL to have multiple tendon slips.3
■ The second dorsal compartment contains the wrist extensors, the ECRB and
ECRL.
■ The ECRB is located ulnarly in relation to the ECRL.
■ The third dorsal compartment contains the EPL tendon and is just ulnar to
Lister tubercle on the radius.
■ The fourth dorsal compartment contains the EIP and EDC tendons. The PIN is
also found within the base of this compartment.
■ The EIP can be identified at the level of the hand and wrist in that it:
• Is ulnar to the index finger slip of the EDC
• Has the distal most muscle belly
• Is the deepest tendon proximal to the extensor retinaculum
• Is not connected by juncturae tendinum
■ The EIP is absent in up to 1% of the population and can have multiple slips
in up to 16% of the population.
■ The fifth dorsal compartment contains the EDM and overlies the distal
radioulnar joint (DRUJ).
■ The EDM is found ulnar to the EDC tendon to the small finger.
■ The EDC tendon to the small finger is often absent, and a double EDM
tendon may occur in 80% to 90% of individuals.4
■ The sixth dorsal compartment contains the ECU tendon.
■ At the level of the hand, the tendons become flat and juncturae tendinum
provides interconnections between the EDC tendons.
■ At the level of the metacarpophalangeal (MCP) joint, the radial and ulnar
sagittal bands form a sling around the extensor tendon and attach to the volar
plate (FIG 1A).
■ Distal to the MCP, the intrinsic muscles of the hand join the extensor tendons
to form the extensor hood.

FIG 1 • A–C. Extensor apparatus at the digit.
■ The central tendon trifurcates at the level of the proximal phalanx, with the
radial and ulnar slips becoming the lateral bands and the central slip inserting
into the base of the middle phalanx by providing proximal interphalangeal
(PIP) joint extension.
■ The interossei split into medial and lateral slips. The medial slip will insert

into the base of the proximal phalanx and functions to flex the MCP joint. The
lateral slip will join with the lateral band of the common extensor tendon to
form the conjoined lateral band. The radial and ulnar conjoined lateral bands
will form the terminal tendon and insert onto the distal phalanx, extending the
DIP joint (FIG 1B,C).
■ The triangular ligament prevents the conjoined lateral bands from volar
subluxation, and the transverse retinacular ligament prevents dorsal
subluxation.1
■ By convention, the extensor tendons are divided into nine zones to assist in
classification of extensor tendon injuries. Odd-numbered zones are located
over joints, and even-numbered zones are located over the long bones (FIG 2):
■ Zone I includes the DIP.
■ Zone II is the middle phalanx.
■ Zone III is the PIP.
■ Zone IV is the proximal phalanx.
■ Zone V is overlying the MCP joint.
■ Zone VI is over the metacarpals.
■ Zone VII includes the carpus and extensor retinaculum.
■ Zone VIII involves the distal forearm, up to the musculotendinous junction of
the tendons.
■ Zone IX involves the remaining part of the upper forearm.
PATHOGENESIS
■ Extensor tendons can be disrupted in a number of ways.
■ Disruption of the terminal tendon in zone I, resulting in a mallet finger, can
occur either through an avulsion of the tendon from its insertion or a fracture of
the base of the distal phalanx at the tendon insertion.
■ The tendons can also be cut from a sharp laceration, and it is not uncommon to
encounter tendon ruptures from attritional wear, from either inflammatory
arthritis or other conditions such as prominent hardware.

FIG 2 • Extensor tendon zones.
NATURAL HISTORY
■ Often, there is an extensor deficit when the tendon is not repaired. In some
cases, such as mallet fingers, the patient can still have a functional hand, even
with the extensor tendon left unrepaired.
■ In other cases, such as a sharp laceration of the EDC at zone VII, there will be
residual impairment.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Patients will often present with a history of a recent trauma in the instance of
extensor tendon laceration or mallet finger (FIG 3).

■ Pain and a history of a pop are common with a mallet finger injury.
■ Patients with attritional rupture, especially patients with inflammatory
arthropathy who already have some functional deficits in their hand, may not
realize that one of their extensor tendons has ruptured.
■ Initial evaluation should include a thorough physical examination, testing all
flexor and extensor tendons, in addition to the digital neurovascular bundles.
■ Upon initial inspection, attention should be paid to the resting cascade of the
digits. If this is disrupted, there is a high likelihood of tendon injury.
■ Wounds should be closely inspected and a determination made of the
cleanliness, sharpness, size, location, and potential for injury with the wound.
■ The function of each extensor tendon should be tested both with and without
resistance. Test each finger individually as the juncturae tendinum may mask
an injury.
■ To test the EIP and EDM, ask the patient to keep the middle and ring fingers
flexed into the palm and extend the index and small fingers.
■ If there is pain and swelling of the PIP joint, coupled with a mild PIP
extension lag or weak PIP joint extension against resistance, one must
consider a central slip injury.
■ The Elson test, in which the DIP joint will become rigid with attempted
extension of the PIP joint from a flexed position, will confirm an early
central slip injury. The DIP becomes rigid because the finger extends through
the intact lateral slips.
■ Active and passive range of motion of all the joints in the hand and wrist
should be tested and recorded.

FIG 3 • Clinical appearance of a mallet finger (zone 1
extensor tendon injury). (Courtesy of Philip Blazar, MD.)
FIG 4 • Radiographic appearance of a bony mallet

injury. (Courtesy of Philip Blazar, MD.)
IMAGING
■ Radiographs of the hand or digit should be taken in orthogonal planes after an
acute extensor tendon injury. This will identify any associated fractures, such
as in a bony mallet injury (FIG 4), and can also identify any foreign bodies
remaining in the extremity after a sharp injury.
■ Ultrasound can be a useful adjunct in the setting of a chronic tendon injury to
determine the position of the proximal and distal tendon ends if direct repair is
being considered.
■ If 4 to 6 weeks have passed since injury, or if the nature of the rupture was
secondary to attritional rupture, direct repair often is not possible because of
shortening of the proximal tendon, and reconstruction or transfer should be
considered.
■ MRI can also aid in determining the position of the tendon ends; however, this
is an expensive modality and can be time-consuming to obtain in some
institutions.
■ In doubtful cases, ultrasound can make a precise determination of the tendon
status.
DIFFERENTIAL DIAGNOSIS
■ Extensor tendon laceration or disruption
■ Adhesions of the extensor tendon system
■ Fracture
■ PIN palsy
■ Radial nerve palsy
NONOPERATIVE MANAGEMENT
■ Nonoperative management of extensor tendon disruption is usually considered
for soft tissue mallet finger injuries and closed central slip avulsions.
■ In closed soft tissue mallet finger injuries, good results can often be obtained
with full-time DIP extension splinting.5 The duration of immobilization varies,
but we usually use an extension splint for 8 weeks followed by 4 weeks of
night splinting.
■ Patient compliance is the most important factor for achieving good outcome
with extension splinting of soft tissue mallet injuries. However, patients

should be counseled that they will likely have a small extensor lag and dorsal
prominence either with or without operative treatment.
■ Surgical indications for soft tissue mallet injuries are debated but
traditionally include open injuries or mallet fractures with volar subluxation
or a fracture fragment larger than 30% to 50% of the articular surface.
■ If there is a closed injury to the central slip, the injury can be treated with
extension splinting of the PIP joint. One must ensure that the full passive PIP
joint extension and DIP flexion can be achieved in the splint.
■ Full-time extension splinting is continued for 6 weeks, followed by 6 weeks
of nighttime splinting.
■ Active flexion exercises of the DIP during this period of immobilization can
help pull the lateral bands dorsally and prevent volar subluxation of the
bands, which can result in a boutonniere deformity.
■ If the tendon injury is incomplete, greater than 50% of the tendon is intact, and
there is no extensor lag or weakness on physical exam, tendon injuries can be
treated nonoperatively with 1 or 2 weeks of splinting.
SURGICAL MANAGEMENT
Preoperative Planning
■ Prior to undertaking surgical repair of the extensor tendons, one must ensure
that they have performed a complete physical examination of the hand and
upper extremity. Other tendon injuries, nerve injuries, fractures, or concomitant
conditions that will need to be addressed surgically should be identified
preoperatively.
■ Radiographs should be obtained to rule out fracture, foreign body, or other
etiology of tendon injury such as inflammatory arthritis or prominent hardware.
■ If the tendon disruption is chronic, a detailed preoperative plan should be
developed to include the possibility of tendon reconstruction or transfer if the
tendon cannot be repaired primarily.
■ If necessary, pinning of the PIP joint is considered.
■ Any additional equipment that may be required to complete and protect a
strong repair should be communicated to the operating room staff in advance,
including hardware and intraoperative fluoroscopy.
Positioning
■ The positioning for the techniques listed below is the same.

■ The patient is placed supine on the operating room table.
■ A hand and upper extremity table extension is attached to the table.
■ A nonsterile tourniquet is applied to the upper arm over padding.
■ The arm is pronated to expose the dorsum of the hand.
■ One or two OR towels are fluffed and placed in the palm of the hand to keep
the fingers extended.
Approach
■ There are a number of described surgical approaches to the dorsum of the DIP,
PIP, and MCP joints as well as the hand, wrist, and forearm.6
■ In general, a longitudinal incision is preferred to allow the surgeon to extend
the incision distally or proximally should the need arise.
■ We prefer to make a gentle S incision over the DIP joint, a radially based
curvilinear longitudinal incision across the PIP and MCP joints and a straight
longitudinal incision over the metacarpals, wrist, and forearm.
■ The incision should take into consideration possible future procedures.
■ If there is a laceration, this is usually extended proximally and distally in a
longitudinal manner to fully explore the wound and injured structures.
■ Distal to the carpus, there is not much subcutaneous tissue between the skin
and the tendon layer. The dissection is brought down sharply to the level of the
tendons or extensor retinaculum with care taken to preserve dorsal veins if
possible.
■ Once the level of the tendon is encountered, full-thickness skin flaps are raised
for full exposure of the tendon ends or extensor retinaculum.
■ If the extensor retinaculum is to be opened, we prefer to identify the EPL
exiting distally and open the retinaculum in line with the third dorsal
compartment to ensure the EPL tendon does not get inadvertently transected.
T E C H N I Q U E S
■ Repair of Open Mallet Injury (Zone I Injury)
■ If the terminal tendon has been sharply transected, it is possible to perform a
primary repair that is then supplemented with Kirschner wire fixation of the
DIP joint in extension.

■ Often, the pre-existing laceration can be incorporated into the incision and
should be extended distally and proximally.
■ Careful sharp dissection of the skin off the terminal tendon is performed,
preferably with a flexible scalpel (Beaver Mini-Blade No. 67, Beaver-Visitec
Int.).
■ Once the terminal tendon has been exposed, insert the K-wire in retrograde
fashion under C-arm fluoroscopy to hold the joint in extension while the
tendon repair is being performed.
■ A determination is made if there is enough remaining terminal tendon in the
insertion of the distal phalanx to facilitate direct repair.
■ If there is enough tendon remaining, a four-strand repair is then performed
using a 4-0 nonabsorbable braided suture, usually in doubled horizontal
mattress configuration if possible or a figure-eight configuration.
■ If there is not enough tendon remaining for a primary repair, the proximal
tendon end can be brought back to the insertion site of the distal phalanx
and secured over a pullout suture button.
■ Repair using one or two microsuture anchors has been described; however,
the insertion of the terminal tendon is immediately adjacent to the origin of
the germinal matrix and the risk of iatrogenic injury to the nail bed makes
this our less preferred technique.
■ A simpler method of repair involves dermatotenodesis (TECH FIG 1).
With this method, one or two 2-0 nylon sutures are placed through the skin
and tendon ends and sutured in a horizontal mattress fashion. The sutures
are left for 3 weeks and then removed. Full-time splinting is continued for a
total of 6 weeks and nighttime splinting for an additional 6 weeks.
■ Once the repair is completed, the wound is copiously irrigated and the skin is
closed with interrupted suture.
■ The joint is protected with an extension splint for the length of time the pin
is in place.
■ We pull the pin at 4 to 6 weeks and continue with nighttime splinting for an
additional 6 weeks.
■ Active and passive range of motion at the PIP and MCP joints is encouraged
to prevent stiffness.

TECH FIG 1 • Example of dermatotenodesis
performed in the ring finger after a zone I extensor
tendon injury. (Courtesy of Philip Blazar, MD.)
■ Closed Mallet Fracture Pinning
■ Ideally, before a closed mallet fracture is brought to the operating room for
surgical repair, one should attempt to obtain radiographs with the digit held in
extension at the DIP joint to see if fracture reduces easily.
■ If seen acutely, oftentimes the fracture will reduce well with extension of
the digit.
■ At the beginning of the procedure, the C-arm is brought in and joint is
visualized radiographically.
■ The DIP joint is then flexed in an attempt to bring the dorsal fragment as far
distal as possible.
■ One 0.028- or 0.035-in. Kirschner wire (K-wire) is then placed just proximal
and dorsal to the dorsal fragment and driven across the DIP joint into the
middle phalanx.
■ The distal phalanx is then extended, and the K-wire should hold the dorsal
fragment in a stable position as the phalanx reduces back to the fragment.
■ Once adequate reduction has been achieved, a second K-wire is inserted in a
retrograde fashion from the tip of the distal phalanx across the DIP joint and

into the middle phalanx.
■ The DIP joint is protected with an extension splint throughout the time the
pins are in place.
■ The pins are pulled in the office at 4 to 6 weeks and nighttime splinting
continues for an additional 6 weeks.
■ Active and passive range of motion at the PIP and MCP joints is encouraged
to prevent stiffness.
■ Zone III Central Slip Repair
■ Zone III injuries overlie the PIP joint and involve the insertion of the central
slip.
■ If left untreated, the lateral bands will migrate volarly and a boutonniere
deformity can develop (PIP joint flexion and DIP joint hyperextension).
■ Central slip repair can be achieved by either primary repair in open
lacerations or injuries or with suture anchors for avulsion injuries.
■ In 1999, Cluett et al.7 found similar biomechanical strengths for both
suture anchor repair and primary repair.
■ For lacerations, the laceration is extended proximally and distally to provide
full exposure of the central slip and assess for any additional injury to the
bone and PIP articular surface.
■ In closed, avulsion-type injuries, a dorsal curvilinear approach is utilized.
This avoids making a longitudinal incision directly over the PIP joint.
■ Skin flaps are raised sharply, taking advantage of the layer between the skin
and the extensor apparatus.
■ The injured central slip is identified and the tendon edges sharply debrided.
■ The PIP joint is pinned in extension with a single 0.035-in. K-wire.
■ If primary repair is to be performed, we prefer to perform the repair using a
running, interlocking, horizontal mattress stitch popularized by Lee et al.8
using a 3-0 or 4-0 braided nonabsorbable suture.
■ If suture anchor repair is to be performed, we prefer to place a single mini
anchor into the central footprint of the middle phalanx. Care is taken to direct
the suture anchor away from the base of the middle phalanx, so as not to
penetrate the joint surface with the suture anchor.
■ Postoperatively, active DIP motion is allowed. The pin is removed from the
PIP joint at 3 weeks. At this point, begin gentle range of motion with hand

therapy and nighttime splinting as needed.
■ Zone V Extensor Tendon Repair
■ Extensor tendon injury at the level of the MCP joint is the most common
location for extensor tendon disruption (TECH FIG 2A).1
■ This zone is also where “fight bite” injuries often occur and special diligence
must be made to ensure the MCP joint is thoroughly irrigated to prevent or
treat an underlying septic arthritis of the MCP joint.
■ There is a high incidence of partial tendon lacerations at this level. Extensor
tendon lacerations involving more than 50% of the tendon should be repaired.
■ Zone V injuries also must take into account the sagittal bands on the radial
and ulnar sides of the MCP joint.
■ If the patient has an acute closed sagittal band rupture, it can often be
treated with extension splinting of the MCP joint for 3 to 4 weeks with the
PIP joint free.
■ Extend the laceration both proximally and distally to ensure there is adequate
exposure of the extensor tendon injury at this level and the MCP joint.
■ Raise skin flaps with sharp dissection in the plane between the skin and the
extensor apparatus.
■ With open injuries, the MCP joint should always be explored and irrigated to
prevent septic arthritis.
■ Evaluate the sagittal band, and if it has been lacerated, perform a primary
repair with a braided absorbable suture after the tendon has been repaired.
■ At this level, the tendon is beginning to become thicker and may
accommodate a core suture. If possible, we prefer to repair the tendon at this
level with either a four-strand repair using 3-0 braided, nonabsorbable suture
or the running, interlocking, horizontal mattress suture configuration
described above (TECH FIG 2B,C).
■ Postoperatively, there has recently been more emphasis on early, controlled
mobilization of the repair.

TECH FIG 2 • A. Initial exploration of a zone V
laceration with disruption of the extensor tendon to the
ring finger. B. Zone VII extensor tendon laceration. C.
Zone VII extensor tendon repair using core sutures.
(Courtesy of Philip Blazar, MD.)
PEARLS AND PITFALLS
Counseling
■ It is important to set realistic expectations with your patients for the
treatment of mallet fingers. Long-term studies have shown that
patients undergoing either surgical or nonoperative treatment will
likely have some degree of mild extensor lag at the end of treatment.
Technique
■ The dorsal skin can be thin and friable. Take extra care to handle the
tissues delicately and develop full-thickness skin flaps.

Indications
■ In soft tissue mallet injuries, splinting is preferable to surgical repair
as the skin is thin and sometimes can die after surgery. In addition,
suture material can be prominent.
Suture
anchors
■ If placing suture anchors into the distal phalanx for a zone I repair, be
careful not to place the anchor into the germinal matrix.
Zone V
injuries
■ Always explore the MCP joint in open injuries. Wound cultures
should be obtained in “fight bite injuries.”
POSTOPERATIVE CARE
■ Traditionally, extensor tendon repairs have been treated with initial
immobilization for longer periods of time when compared with flexor tendon
repairs.
■ There is some evidence that for zone V and VI repairs, there are better short-
term functional results with early mobilization protocols. There is some
evidence of short-term superiority of early, controlled mobilization of extensor
tendon repairs but no evidence of long-term superiority of early motion
compared with immobilization9; plus, there is a higher risk of tendon repair
rupture.10,11
■ For zone I, II, and III repairs, immobilization of the DIP and PIP joints
respectively in extension for 6 weeks after repair is reasonable.
■ At that time, range of motion exercises can begin and nighttime splinting
initiated for an additional 6 weeks.
■ Be sure to move the remaining joints of the finger to help prevent stiffness of
the entire digit.
■ For zone IV, V, and VI repairs, the MCP joints respectively are immobilized
for about 4 weeks in extension, followed by gentle range of motion in
conjunction with hand therapy. There is variation regarding immobilizing the
PIP joints.
OUTCOMES
■ Kalainov et al.12 treated 21 patients with mallet fractures in which greater than
one-third of the articular surface was involved with splinting in a 2005
retrospective study. They had good results in terms of pain and function, but
their follow-up averaged only 2 years.
■ Outcomes of surgical treatment for mallet injuries have been comparable
across the various techniques. Most patients will have an extensor lag from 2 to

7 degrees and flexion ranged from 67 to 78 degrees.13–16
■ Pratt et al. reported on 27 patients who underwent zone III repairs and were
treated with a postoperative protocol that consisted of static immobilization for
3 weeks and early controlled motion for an additional 3 weeks. Twenty-two of
27 patients had good results with mean PIP flexion of 94 degrees. Five fingers
had extension lags of an average of 6 degrees.17
■ Newport et al. reported on 101 digits that underwent extensor tendon repair
and were treated postoperatively with static splinting.18 They found that
patients with associated injuries (fracture, dislocation, flexor tendon injury) and
distal repairs (zones I–IV) did worse than those without injuries and proximal
repairs, with flexion loss being the most significant complication.
COMPLICATIONS
■ Infection
■ Tendon rupture
■ Extensor lag
■ Wound dehiscence
■ Adhesions and stiffness
■ Nail deformities
REFERENCES
1. Matzon JL, Bozentka DJ. Extensor tendon injuries. J Hand Surg [Am].
2010;35(5):854-861.
2. Branovacki G, Hanson M, Cash R, Gonzalez M. The innervation pattern of
the radial nerve at the elbow and in the forearm. J Hand Surg Br.
1998;23(2):167-169.
3. Gonzalez MH, Sohlberg R, Brown A, Weinzweig N. The first dorsal extensor
compartment: an anatomic study. J Hand Surg [Am]. 1995;20(4):657-660.
4. Celik S, Bilge O, Pinar Y, Govsa F. The anatomical variations of the extensor
tendons to the dorsum of the hand. Clin Anat. 2008;21(7):652-659.
5. Handoll HH, Vaghela MV. Interventions for treating mallet finger injuries.
Cochrane Database Syst Rev. 2004;(3):CD004574.
6. Cheah AE, Yao J. Surgical approaches to the proximal interphalangeal joint. J
Hand Surg [Am]. 2016;41(2):294-305.
7. Cluett J, Milne AD, Yang D, Morris SF. Repair of central slip avulsions using
Mitek Micro Arc bone anchors: an in vitro biomechanical assessment. J Hand
Surg Br. 1999;24(6):679-682.

8. Lee SK, Dubey A, Kim BH, et al. A biomechanical study of extensor tendon
repair methods: introduction to the running-interlocking horizontal mattress
extensor tendon repair technique. J Hand Surg [Am]. 2010;35(1):19-23.
9. Talsma E, de Haart M, Beelen A, Nollet F. The effect of mobilization on
repaired extensor tendon injuries of the hand: a systematic review. Arch Phys
Med Rehabil. 2008;89(12):2366-2372.
10. Mowlavi A, Burns M, Brown RE. Dynamic versus static splinting of simple
zone V and zone VI extensor tendon repairs: a prospective, randomized,
controlled study. Plast Reconstr Surg. 2005;115(2):482-487.
11. Bulstrode NW, Burr N, Pratt AL, Grobbelaar AO. Extensor tendon
rehabilitation: a prospective trial comparing three rehabilitation regimes. J
Hand Surg Br. 2005;30(2):175-179.
12. Kalainov DM, Hoepfner PE, Hartigan BJ, et al. Nonsurgical treatment of
closed mallet finger fractures. J Hand Surg [Am]. 2005;30(3):580-586.
13. Moradi A, Kachooei AR, Mudgal CS. Mallet fracture. J Hand Surg [Am].
2014;39(10):2067-2069.
14. Hofmeister EP, Mazurek MT, Shin AY, Bishop AT. Extension block pinning
for large mallet fractures. J Hand Surg [Am]. 2003;28(3):453-459.
15. Fritz D, Lutz M, Arora R, et al. Delayed single Kirschner wire compression
technique for mallet fracture. J Hand Surg Br. 2005;30(2):180-184.
16. Lu J, Jiang J, Xu L, et al. Modification of the pull-in suture technique for
mallet finger. Ann Plast Surg. 2013;70(1):30-33.
17. Pratt AL, Burr N, Grobbelaar AO. A prospective review of open central slip
laceration repair and rehabilitation. J Hand Surg Br. 2002;27(6):530-534.
18. Newport ML, Blair WF, Steyers CM Jr. Long-term results of extensor tendon
repair. J Hand Surg [Am]. 1990;15(6):961-966.

42
CHAPTER
Stabilization of Extensor
Carpi Ulnaris Tendon
Subluxation With Extensor
Retinaculum
Michael Smith, Jacques A. Machol IV, and Neal Chen
DEFINITION
■ Symptomatic recurrent extensor carpi ulnaris (ECU) subluxation over the
ulnar head with forearm rotation can be a cause of ulnar-sided wrist pain. Not
all patients with subluxation of the ECU are symptomatic, and painless
subluxation is not an absolute indication for surgery.
■ Symptomatic ECU instability manifests in patients who play sports such as
tennis, hockey, squash, golf, or baseball.
■ It is suspected that snapping of the ECU over the ulnar head with resisted
supination, flexion, and ulnar deviation is the mechanism that leads to
symptoms.
ANATOMY
■ The ECU tendon runs through the sixth dorsal compartment following an
angular path across the ulnar head as it travels from its muscle origin on the
lateral epicondyle to its insertion on the base of the fifth metacarpal.
■ The ECU ulnarly deviates and extends the wrist. The ulnar deviation is
counterbalanced by the radially deviating forces of the abductor pollicis
longus, extensor carpi radialis longus, and the extensor carpi radialis.
■ The ECU tendon lies just dorsal to the flexion/extension axis of the wrist;
therefore, the tendon is at risk for subluxation volar to the flexion/extension
axis with hypersupination of the forearm and flexion with ulnar deviation of
the wrist.1

■ The ECU tendon is stabilized by the extensor retinaculum.
■ The ECU tendon runs through a fibro-osseous tunnel at the level of the distal
ulna called the ulnar groove.
• The average ECU groove depth measures approximately 1.4 mm, and the
radius of curvature is approximately 7.0 mm.2
■ In addition, the ECU has its own subsheath, which consists of an overlying
band of connective tissue measuring 1.5 to 2.5 cm in length that functions to
keep the ECU tendon within the ulnar groove.
■ There are transverse fibers of the medial wall of the ECU compartment that
extend proximally and become confluent with the ECU epimysium. These
fibers help prevent volar subluxation of the tendon during supination.2,3
■ The ECU subsheath stabilizes the ECU during forearm rotation, while the
extensor retinaculum helps prevent bowstringing of the extensor tendons.
■ The ECU subsheath also contributes to the dorsal portion of the triangular
fibrocartilage complex.
■ The distal subsheath contributes more to ECU stability than does the proximal
half of the subsheath.4
■ Wrist flexion and supination are positions of relative instability for the ECU
subsheath.4
PATHOGENESIS
■ Incompetence of the ECU subsheath, whether through attritional wear or acute
traumatic injury, is thought to lead to ECU instability.
■ Laxity in the ECU subsheath and painless snapping over the ulnar head may
be a normal variant, especially in individuals that are ligamentously lax.
■ It is proposed that traumatic wrist flexion, ulnar deviation, and supination can
result in rupture of the ECU subsheath from its ulnar attachments and lead to
the subluxation of the tendon out of the distal ulnar groove.1
■ Symptomatic patients may demonstrate a snap when the wrist is placed in the
at-risk position of flexion, ulnar deviation, and supination.
■ ECU instability injuries were classified by Inoue and Tamura and separated
into three distinct types.
■ The ECU subsheath can have detachment along the ulnar border (type A), the
radial border (type B), or a periosteal detachment with expansion of the
sheath, creating a false pouch that allows subluxation of the tendon from the
ulnar groove (type C).5,6

NATURAL HISTORY
■ If left untreated, chronic instability of the ECU tendon can exacerbate ECU
tendinopathy as the tendon snaps over the ulnar prominence of the ulnar
groove.
■ Some authors have theorized that chronic dislocation of the ECU tendon may
lead to distal radioulnar joint (DRUJ) instability and eventual degenerative
changes at the DRUJ. This phenomenon is uncommon.
■ There are some patients who have naturally lax ligaments and have a degree of
subluxation of the ECU tendon without previous injury. Their ECU instability
is often bilateral and asymptomatic and found incidentally on exam.
■ In general, we recommend observing these patients.
PATIENT HISTORY AND PHYSICAL FINDINGS
■ Patients are often younger and participate in stick or racket sports such as
tennis, golf, baseball, or hockey.
■ Patients will complain of recurrent, painful snapping over the dorsoulnar wrist
with wrist supination and pronation that limits their participation in sports,
hobbies, or activities of daily living.
■ There may be a history of a specific, acute injury.
■ On physical exam, the ECU tendon can be palpated subluxating over the ulnar
head with circumduction of the wrist.
■ Sometimes, supination and ulnar deviation against resistance are required to
produce the snapping.
■ If the ECU is irritated, it will often be most painful with full passive radial
wrist flexion.
■ Occasionally, the clinical exam is inconclusive if the patient is not able to
voluntarily subluxate the ECU tendon.
■ Painful subluxation of the ECU tendon is an important component of the
physical examination, and the surgeon should be cautious if contemplating
surgical treatment in the patient who does not have painful demonstrable ECU
instability.
■ Careful examination of the contralateral wrist should be done to ensure that the
patient does not have asymptomatic subluxation of the ECU tendon as a natural
variant and the patient’s complaints do not have another etiology.
■ Other etiologies for the patient’s pain are ruled out, such as ulna impaction,
ECU tendinosis, DRUJ instability, LT instability, or TFCC tears.

IMAGING
■ Routine anteroposterior, lateral, and oblique radiographs of the wrist are
obtained to rule out other pathologies that may be causing ulnar-sided
discomfort such as fracture or DRUJ arthritis.
■ It is important to note positive ulnar variance, as this can indicate ulnocarpal
impaction.
■ MRI is an option to evaluate for tendon subluxation; however, this is often a
dynamic phenomenon that may not be visualized using a static MRI.
■ Some authors suggest performing an MRI with both wrists positioned in
pronation, neutral, and supination. This provides a comparison with the
contralateral wrist to show the ECU tendon within the ulnar groove in all
three positions. However, the usefulness of this imaging technique is debated.
■ Other pathologies, such as TFCC tears, ECU tendonitis, or longitudinal tears,
may be visualized with MRI, but the clinical significance of these findings
needs to be considered thoughtfully.
■ Dynamic ultrasound may demonstrate ECU subluxation out of the ulnar
groove for patients in whom there was not definitive snapping or subluxation
elicited during physical exam.7–9 The role of dynamic ultrasound is still in
evolution.
DIFFERENTIAL DIAGNOSIS
■ ECU tendonitis
■ Triangular fibrocartilage complex tear
■ Ulnocarpal impaction
■ Carpal instability
■ DRUJ instability
■ DRUJ arthritis
■ Ulnar nerve entrapment
NONOPERATIVE MANAGEMENT
■ In acute injuries, 4 to 6 weeks of either a long-arm or Muenster cast
immobilization is usually sufficient.
■ Some authors recommend immobilizing in pronation and slight radial
deviation, which allows the ECU subsheath to heal to the ulnar edge of the
ulnar groove.1
■ After cast removal, a custom splint is applied and progressive return to activity

is begun in conjunction with occupational therapy.
■ Full, unrestricted activity is usually achieved by 3 months if the patient is no
longer painful.
■ After treatment, some patients will have asymptomatic subluxation.
SURGICAL MANAGEMENT
■ For patients in whom symptomatic instability of the ECU tendon persists after
a period of immobilization and therapy, operative treatment is considered (FIG
1).
■ If the ECU sheath is incompetent, a retinacular sling reconstruction should be
elected. An ulnar groove deepening is performed only if the sheath is
competent.
■ Some authors prefer sling reconstruction for all cases.
Preoperative Planning
■ If a patient has an MRI present, it is useful to evaluate the anatomic details to
understand if there is a type A, B, or C subluxation.
Positioning
■ The patient should be positioned supine on the operating room table with the
operative extremity on a hand or upper extremity table.
■ Prior to draping the arm, perform an exam under anesthesia to recreate the
ECU instability. It is important to note the position of instability preoperatively
so one can confirm that the stabilization is effective once completed.
■ A nonsterile tourniquet is placed on the upper arm to facilitate hemostasis.
■ The arm is held in pronation to facilitate a dorsal approach to the ECU tendon.

FIG 1 • Anatomic ECU tendon sheath reconstruction. A.
Exposure of the 6th dorsal compartment and elevation
of the extensor retinaculum. B. Imbrication of the
extensor retinaculum and subsheath. C. Final fixation of
the extensor retinaculum and subsheath after
imbrications.
T E C H N I Q U E S
■ Exposure
■ The arm is exsanguinated and the tourniquet is inflated.

■ A 5-cm longitudinal incision is made overlying the sixth dorsal compartment
and ECU tendon (TECH FIG 1).
■ After the skin is incised, blunt dissection is carried out through the
subcutaneous fat to identify and protect the dorsal cutaneous branch of the
ulnar nerve.
■ The extensor retinaculum over the sixth compartment should be sharply
incised in a longitudinal fashion on its ulnar-most border and the retinaculum
carefully dissected off of the underlying ECU subsheath.
TECH FIG 1 • Marked incision for ECU retinacular
sling reconstruction. (Courtesy of Philip Blazar, MD.)
■ Retinacular Sling Reconstruction of the ECU
Subsheath
■ The extensor retinaculum is carefully dissected from its ulnar border to
expose the ECU subsheath (TECH FIG 2A).
■ Once the ECU subsheath is fully exposed, the type of pathology (type A, B,
or C) of the subsheath is noted and the wrist is taken through a full arc of
motion from pronation to supination to gauge the behavior of the tendon
through wrist range of motion.
■ At the level of the ECU subsheath, overlying the ulnar groove, a 3-cm

rectangular flap of retinaculum is developed starting at the second
compartment; the base of which is the septum between the fifth and sixth
dorsal compartments (TECH FIG 2B).
■ This sling of retinaculum is then passed from radial to ulnar, volar to the
ECU tendon, and folded back to the base of the flap (TECH FIG 2C).
■ A trial stitch should be placed in order to assess the tightness of the sling in
pronation, neutral, and supination in both wrist flexion and extension (TECH
FIG 2D).
■ The sling should not constrict the tendon, but it must still prevent
subluxation of the ECU tendon about the ulnar head.
■ The flap is sutured to itself using 3-0 nonabsorbable, braided suture.
■ The remainder of the extensor retinaculum is anatomically repaired to ulnar
border of the retinaculum using an absorbable suture.
■ The tourniquet is let down, and hemostasis is confirmed.
■ The wound is copiously irrigated, the dorsal incision is sutured, and the
patient is placed into a sugar-tong splint with the wrist in mild pronation,
extension, and radial deviation.