Phẫu Thuật Tạo Hình Grabb & Smith’s (Bản Cập Nhật – Kevin C. Chung)

After reduction is achieved, a well-padded plaster splint is applied. Circumferential casting is not
recommended in the acute setting because a cast does not accommodate postinjury swelling. For most
fractures, a short arm dorsoradial splint out to the level of the metacarpal heads is adequate to
immobilize the wrist. Routine use of a sugar-tong splint is common, and Smith fractures and fractures
that involve the DRUJ require sugar-tong splinting to control pronosupination. The plaster should be
molded and the wrist positioned to oppose the initial pattern of fracture displacement. For a classic Colles
fracture, this entails a three-point mold with two points of dorsal pressure proximal and distal to the
fracture, and a single point of volar pressure at the level of the fracture. This functions to maintain tension
on the intact dorsal periosteal hinge and opposes dorsal displacement. This fracture pattern is
immobilized in slight wrist flexion and ulnar deviation. Extremes of flexion/extension and radioulnar
deviation should be avoided.
Patients treated initially with closed reduction and plaster immobilization should be followed closely for
interval radiographs to ensure that reduction has been maintained. Not infrequently, a fracture of
uncertain stability will be treated with initial closed reduction and immobilization and then undergo
interval displacement, resulting in conversion to operative treatment. If ongoing closed treatment is
planned, the splint should be adapted as the padding compresses and swelling decreases in order to
maintain the mold. Transition to a cast is made at 2 weeks and generally continued until 4 weeks
postinjury for minimally displaced fractures and 6 weeks for fractures that had initial displacement or
comminution. A removable splint is then applied and weaned over the ensuing month. 13
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Closed Reduction and Percutaneous Pinning
Percutaneous pinning of the distal radius is applicable to extraarticular or simple articular fractures
without metaphyseal comminution that are reducible, but unstable after reduction. It is not indicated in
severely comminuted or osteoporotic fractures. Pinning is performed in the operating room under
fluoroscopic control, usually utilizing 0.062 in Kirschner wires. Several methods of pin fixation have been
described—we prefer transradial styloid and Kapandji (intrafocal) pinning.
Transradial styloid pinning simply entails closed reduction of the fracture with or without the use of
intraoperative traction. This is followed by placement of one or two retrograde pins beginning in the tip
of the radial styloid, directed across the metaphyseal fracture line and into the volar-ulnar cortex of the
radius. This may be supplemented by an additional retrograde pin beginning dorsally between the fourth
and fifth extensor compartments and directed in a volar-radial direction.
Kapandji (or intrafocal) pinning entails insertion of pins directly into the fracture site from the volar-
radial and dorsoulnar aspects. These pins are then levered distally to reduce the fracture and restore
radial height/inclination and volar tilt, respectively, before being advanced into the opposite cortex to
maintain the reduction. 14
These techniques have the advantage of low cost and easy removal of all hardware in the office. Concerns
of percutaneous pinning include neurovascular injuries during pin placement 15 and pin tract infections.
Additionally, pin constructs do not provide rigid fixation, limiting early rehabilitation of the wrist.
Required immobilization with closed reduction percutaneous pinning is one reason many surgeons
prefer volar locking plate (VLP) fixation, despite some metaanalyses that report similar outcomes with
both techniques. 16
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Volar Locking Plate Fixation
Since its introduction by Orbay and Fernandez, 17 VLP fixation has become a popular method for treating
distal radius fractures. Even though a wide variety of proprietary devices are available, basic plate design
involves a narrow proximal stem that affixes to the radial shaft and a wide distal end, which abuts (and
potentially buttresses) the volar aspect of the radial metaphysis with screws or pegs to support articular
surface (Figure 75.7). This construct transmits load from the articular surface, via the subchondral locking
pegs to the strong volar radial cortex, thereby opposing secondary displacement, even in cases of severe
metaphyseal 
 comminution. Subchondral locking pegs provide enough support that bone grafting of
dorsal metaphyseal defects is rarely 
 necessary. Fracture fixation using a VLP is demonstrated in Figure
75.8.
FIGURE 75.7 Anatomy of a volar locking plate.
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FIGURE 75.8 Preoperative (A, B) and postoperative (C, D) radiographs demonstrating use of a volar locking plate to stabilize
a distal radius fracture.
Application of a VLP is generally done through a flexor carpi radialis approach. After fracture exposure
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and mobilization, the fracture may be reduced and the plate is used to stabilize the fracture. The plate
must be placed proximal to the watershed line to avoid irritation of the flexor tendons, 18 but not so
proximal that the locking pegs fail to support the subchondral bone (Figure 75.9).
FIGURE 75.9 A. The watershed line is a transverse ridge located between the distal border of the pronator quadratus and the
origin of the volar extrinsic ligaments of the wrist (yellow line). It marks the most prominent portion of the volar distal radius and
is thus point of contact for overlying flexor tendons. Volar locking plates should ideally be positioned proximal to the watershed
line. B. Radiographically, this can be checked by ensuring that the plate does not protrude beyond a tangent line dropped from
the most volar portion of the distal radius as visualized on lateral radiograph.
Advantages of VLP fixation include wide applicability, absence of a need to routinely remove hardware,
and a low rate of tendon irritation/rupture. The rigid nonspanning fixation offered by a VLP allows early
mobilization and rehabilitation of the injured wrist. 19
Limitations of the volar approach include poor visualization of dorsal articular surface and centrally
impacted fractures. Small but crucial volar or dorsal ulnar corner fragments may be difficult to capture
with standard VLP, requiring additional fixation or fragment-specific plates. 20
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Dorsal Plating
Prior to introduction of the VLP, dorsal buttress plating of the distal radius was common. This approach
offered easy exposure, facilitated subchondral bone grafting, and allowed effective buttressing of dorsally
displaced fractures. Additionally, this approach allowed direct visualization of the articular surface and
intercarpal ligament injuries via a dorsal capsulotomy. Unfortunately, dorsal plates were prone to irritate
and sometimes rupture the extensor tendons, 21 and hardware removal was frequently required. For this
reason, dorsal buttress plating has been supplanted by the VLP as the fixation method of choice for most
fracture patterns. Despite this, some fracture patterns are still preferably managed with dorsal plates.
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Fragment-Specific Fixation
In some cases, critical articular fracture fragments may be too small to support multiple locking
screws/pegs. Furthermore, placing a VLP distal enough to capture small volar rim fragments may cause
irritation or rupture of overlying flexor tendons. In these situations, fragment-specific fixation can be used.
This is a system of ultralow profile miniplates, pin plates, hook plates, and wireforms anatomically
designed to fix a single common articular fracture fragment (see Classification section above). While this
technique often requires both dorsal and volar approaches to the distal radius, each approach can be done
with minimal soft tissue dissection owing to the smaller size of the implants (Figure 75.10).
FIGURE 75.10 Posteroanterior (A) and lateral (B) views of an intra-articular fracture of the distal radius treated with fragment-
specific plating of the dorsal ulnar fragment and K-wire fixation of the radial styloid fragment.
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External Fixation and Bridge Plating
External fixation can be used for temporary or definitive treatment of many distal radius fractures,
though it is most commonly used in highly comminuted and shortened fracture patterns. Additional
indications include situations of excessive edema or substantial soft tissue injury. External fixators
maintain length while aligning the joint surface with the radial shaft. The most common configuration is a
radiocarpal spanning uniplanar fixator anchored in the radial shaft and second metacarpal. More
complex designs including dynamic devices, fixators that do not span the radiocarpal joint, and a device
offering multiplanar control are also available. 12
Advantages of external fixation include the ease of application and avoiding the devascularization of
multiple small bony fragments that can occur during open reduction internal fixation. Limitations include
the external frame, the risk of pin-related infection, and potential injury to tendons and nerves.
To avoid external pins, dorsal bridge (aka spanning or distraction) plating can be used for similar fracture
patterns. 22 A straight plate is affixed to the dorsal radial shaft and proximal second or third metacarpal,
spanning and distracting the fracture to maintain length and axial alignment. This device is mechanically
similar to a uniplanar external fixator, in that it provides distraction across the fracture and does not
disrupt its vascularity, but the plate sits closer to the fracture and thus provides increased stability. The
plate is generally removed at 12 weeks, during which time the wrist should be immobilized to prevent
plate breakage.
Because this load-bearing fixation technique allows early weight bearing upon the injured extremity, it is
useful in polytrauma patients with multiple injured extremities. A limitation of both external and internal
spanning fixations is that ligamentotaxis cannot alone reliably maintain reduction of displaced and
impacted articular fragments. For this reason, external and internal spanning fixation is often augmented
with other hardware (i.e., K-wires, fragment-
 specific plates) to maintain articular reduction (Figure
75.11).
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FIGURE 75.11 Posteroanterior (A) and lateral (B) views of an intraarticular fracture of the distal radius treated with a dorsal
bridge plate augmented by a K-wire in the radial styloid. Two radioulnar pins were also used for treatment of traumatic instability
of the distal radioulnar joint.
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Associated Injuries
Median Nerve Dysfunction
Median nerve dysfunction associated with distal radius fracture is usually due to nerve stretching over a
dorsally angulated fracture. Accumulation of hematoma within the carpal tunnel may also irritate and
compress the nerve. Median nerve function (two-point discrimination, thenar motor function) should be
assessed and documented before and after reduction. If median nerve function worsens or does not
improve after reduction, carpal tunnel release (and often surgical treatment of the fracture) is indicated.
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Ulnar Styloid Injuries
Ulnar styloid fractures occur commonly with distal radius fractures. They are not independently
predictive of outcomes, and the presence of even a large ulnar styloid fragment does not necessarily
indicate DRUJ instability. 23 If a large styloid fragment is present in a fracture with DRUJ instability after
fixation of the radius, repair of the ulnar styloid is indicated.
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Distal Radioulnar Joint Instability
Evaluation of every distal radius fracture should include assessment of DRUJ stability in neutral,
supination, and pronation. Following fixation of the radius, the ulna is stabilized in one hand and the
radius is shucked in an AP direction. Laxity varies among individuals, so suspected instability should
always be compared to the uninjured side. If DRUJ instability is detected, this may represent a TFCC
disruption.
Treatment for DRUJ instability is based upon fracture pattern and the positions of maintained forearm
stability. If a large ulnar styloid fragment is present, this may be fixed with a K-wire, tension band, or
screw, thereby reestablishing the TFCC’s constraint of the DRUJ. If the DRUJ is stable in supination,
postoperative immobilization in this position for 3 weeks and then in neutral for another 3 weeks often
allows soft tissue healing to the point that DRUJ stability is restored. If the joint is unstable in supination,
TFCC repair or DRUJ pinning is indicated. 24
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Intercarpal Ligament Injuries
Scapholunate and lunotriquetral interosseous ligament tears occur with 16% to 40% and 8.5% to 15% of
distal radius fracture respectively. 25 Plain radiographs may suggest the diagnosis, but magnetic
resonance imaging (MRI) or arthroscopy can be used to guide treatment. High physical demand patients
with static or dynamic carpal instability may benefit from interosseous ligament repair. 25
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Complications
Complications include stiffness, posttraumatic arthrosis of the radiocarpal or distal radioulnar joint, and
complex regional pain syndrome (CRPS). CRPS is characterized by pain out of proportion to the injury,
edema, vasomotor instability, and stiffness. There is conflicting evidence regarding ascorbic acid reducing
the risk of CRPS. In this setting, electrodiagnostic studies to evaluate for peripheral nerve compression
are important as missed peripheral nerve compression are easily treatable and can be a cause of CRPS. 26
Early referral to a pain management specialist for initiation of multimodality treatment 27 and to a hand
therapist for edema control and joint mobilization are important adjunctive treatments.
Attritional rupture of the extensor pollicis longus after distal radius fracture results from increased
pressure within the third extensor compartment and is most often seen in minimally displaced fractures
treated nonoperatively. Both flexor and extensor tendon irritation can result from contact with a
prominent plate or screw tip. 27 When applying a VLP, this problem can be mitigated by proper implant
placement, and choosing distal locking screw/pegs that do not penetrate the dorsal cortex. Biomechanical
studies demonstrate support of 75% or articular surface is sufficient to resist displacement. 28 Unexplained
pain or crepitus with active range of motion at any interval following plate fixation requires radiographic
evaluation, and consideration should be given to removal or exchange of hardware depending on
fracture healing.
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Rehabilitation of Distal Radius Fractures
Rehabilitation of a distal radius fracture begins promptly after diagnosis. Finger motion is encouraged
immediately. The period of strict immobilization following initial fracture treatment will vary based upon
the fracture pattern, bone quality, fixation method, patient predisposition, and surgeon preference.
Therapeutic concerns and specific protocols for each type of fixation have been described in detail by
Slutsky and Herman. 29 In general, the era of rigid VLP fixation has been marked by enthusiasm for early
active wrist and forearm motion. After fracture healing, late concerns include scar management and
desensitization, strengthening, and restoration of advanced/occupational activities.
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Outcomes Assessment
Many level III to IV studies have been published concerning the outcomes of treatment for distal radius
fracture. Unfortunately, high-level evidence is still lacking, in part due to the widely varied and
incomplete methods of assessment that have been employed. The Distal Radius Outcomes Consortium
has recently developed a consensus Unified Approach to Outcomes Assessment for Distal Radius
Fractures. 30 In this document, the consortium outlines minimum outcomes to capture after distal radius
facture, subdivided into the domains of performance measures, patient reported outcomes, pain,
complications, and radiographs. It is their aim that widespread adoption of these measures will provide a
deliberate and systematic assessment of both treatment effectiveness and quality that is accessible for
review and comparison.
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Scaphoid Fractures
Epidemiology
The scaphoid accounts for 60% to 70% of all carpal fractures, and like fractures of the distal radius, it
often fractures after falling onto an outstretched hand. Their incidence has been calculated at 12.4 per
100,000 personyears, with a peak occurring in men between the ages of 15 and 19 years. 31
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Anatomy
The scaphoid is the link between the proximal and distal carpal rows, and is described as proximal and
distal poles with an intervening waist. The proximal pole articulates with the lunate and the scaphoid
fossa of the distal radius, the waist articulates with the capitate, and the distal pole articulates with the
trapezium and trapezoid (see Figure 75.1). About 75% to 80% of scaphoid fractures occur at the waist,
10% to 15% occur at the proximal pole, and 5% to 10% occur distally.
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Biomechanics of Injury
Scaphoid fractures most commonly occur after fall on an outstretched hand, which causes impaction of
the proximal pole upon the dorsal rim of the distal radius. Waist fractures occur around the
radioscaphocapitate ligament, which acts as a fulcrum. After scaphoid waist fracture, the distal fragment
tends to flex and the proximal fragment tends to extend due to its strong lunate attachment via the
scapholunate interosseous ligament. This can be visualized radiographically as an elevated lateral
intrascaphoid angle (>35°) and humpback deformity on the lateral projection.
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Vascularity
The scaphoid is almost entirely covered by articular cartilage; it has a delicate vascular supply with
greater than 70% of the scaphoid’s intraosseous vascularity from the dorsal scaphoid branches of the
radial artery. These vessels enter the dorsal ridge in a retrograde direction, providing the single dominant
intraosseous vessel to the proximal pole of the scaphoid. A minor volar contribution comes from the
radial artery or its superficial palmar branch. 32 Because of this unique vascular anatomy, the proximal
pole of a fractured scaphoid is particularly prone to avascular necrosis and nonunion, especially when the
fragment is small.
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Classification
At least 13 distinct schemes for classification of acute scaphoid fractures have been proposed based upon
assessment by plain radiography. Schemes generally divide fractures by anatomical location, fracture
plane orientation, and/or stability and displacement. 33 The most commonly cited classification scheme is
the modified Herbert 34 system followed by the Russe 35 system. A summary of the modified Herbert and
Russe classifications can be found in Tables 75.2 and 75.3.
TABLE 75.2
Modified Herbert Classification of Scaphoid Fractures
Type
Description
Depiction
Stability
A1
Tubercle
Stable
A2
Incomplete waist
B1
Distal oblique
Unstable
B2
Complete waist
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B3
Proximal pole
B4
Fracture dislocation
Varies, usually waist fracture
D1
Fibrous union
Nonacute
D2
Pseudoarthrosis
D3
Sclerotic pseudoarthrosis
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TABLE 75.3
Russe Classification of Scaphoid Fractures
Type
Description
Depiction
Stability
D4
Avascular necrosis
HO
Horizontal oblique
Most stable
T
Transverse
Intermediate stability
VO
Vertical oblique
Least stable
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Radiographic Evaluation
Physical examination has a high sensitivity and low specificity for detecting acute scaphoid fractures, so
radiographs including PA, lateral, pronated and supinated oblique, and scaphoid views are utilized.
Approximately 20% of patients with negative radiographs have an occult acute fracture. Clinical
suspicion with negative radiographs has historically been followed by immobilization in a thumb spica
cast and follow-up radiographic examination at 2 weeks. This strategy still fails to detect 9% of scaphoid
fractures, results in delayed fracture diagnosis, and unnecessarily immobilizes many patients. For these
reasons, early advanced imaging in patients with negative plain films and suspicion for a fracture based
upon history or examination findings has become increasingly popular. MRI is the most sensitive and
specific imaging modality for diagnosing scaphoid fractures and also allows assessment of osseous blood
supply and soft tissue injuries. Computed tomography (CT) scan reformatted in the long axis of the
scaphoid is slightly less sensitive and specific for identification of scaphoid fracture, but has the
advantage of superior bony detail. 36
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Operative Indications
Operative indications are dependent upon fracture alignment and stability. Nondisplaced fractures may
be treated with immobilization. Indications for operative management of the fractured scaphoid include
37
Greater than 1 mm of displacement at the waist
Lateral intrascaphoid angle >35°
Bone loss or comminution
Dorsal intercalated segment instability
Malalignment
Any proximal pole fracture
Delayed presentation is also a relative indication for surgery, as this population has an increased risk of
nonunion with nonoperative treatment. Because of the scaphoid’s retrograde vascular supply, distal pole
and tubercle fractures have a low incidence of nonunion and can generally be treated nonoperatively.
Less invasive surgical techniques have resulted in an increased operative treatment of nondisplaced
scaphoid waist fractures. Proponents cite improvements in union rate and earlier mobilization, but
outcomes studies examining operative versus nonoperative management of nondisplaced scaphoid waist
are inconclusive. 38
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Nonoperative Treatment
Nonoperative treatment is reserved for nondisplaced scaphoid waist and distal pole fractures. Repeat
images at 2 weeks are obtained to verify if alignment has been maintained. Above elbow thumb spica,
short arm thumb spica and simple short arm casting have all been advocated, without conclusive
evidence one method is superior. Recently, a randomized trial demonstrated better healing when the
thumb is not included. 39
The duration of immobilization depends upon the patient and the location of the fracture. Distal pole and
tubercle fractures generally require only 6 to 8 weeks to heal, whereas scaphoid waist fractures usually
require 12 weeks. Immobilization can be discontinued when bony union has been demonstrated. We
advocate CT scan to confirm healing between 10 and 12 weeks, when the fracture is no longer visible on
plain radiographs.
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Open Reduction and Internal Fixation
Until the mid-1980s, most scaphoid fixation was performed using Kirschner wires. In 1984, Herbert and
Fisher popularized the use of headless compression screws, revolutionizing the treatment of scaphoid
fractures. 40
The initial screw was not cannulated and required a jig for insertion. Subsequently, a cannulated
modification (Herbert-Whipple screw) was developed, allowing insertion over a fluoroscopically targeted
guidewire. 41 When there is bone loss or comminution, cancellous or corticocancellous autogenous bone
graft from the distal radius can be used to fill the void and aid in healing.
Fracture location often dictates the surgical approach. Because of the volar obliquity of the scaphoid axis,
proximal pole fractures are more easily visualized using a dorsal approach, whereas distal pole fractures
are amenable to a volar approach. Waist fractures can be addressed from either side, with advantages and
drawbacks to each. A volar approach provides wide bony exposure, and facilitates correction of a
humpback deformity using structural bone graft to support the collapsed volar cortex. However, the
volar margin of the trapezium hinders retrograde screw placement. The dorsal approach to a scaphoid
waist fracture provides an unobstructed path for screw placement, but exposure is more limited, and
bone grafting for correction of a humpback deformity is more difficult from the dorsal approach.
Furthermore, the dorsal location of the dominant blood supply is at risk with distal exposure.
Percutaneous and mini-open techniques can be performed from dorsal or volar with minimal soft tissue
and vascular disruption. 42 These approaches are best suited for nondisplaced fractures, though displaced
fractures can still be treated percutaneously with the aid of joystick manipulation using Kirschner wires
and arthroscopic visualization.
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Postoperative Management and Rehabilitation
After surgical treatment of a scaphoid fracture, the patient is immobilized in a short arm splint with or
without a thumb spica component. Finger motion is initiated immediately and the surgical dressing is
changed at 2 weeks to a cast or removable brace. Some surgeons allow intermittent splint removal for
light active range of motion exercises at the wrist even before bony union. Assessment of bony union is
variable among surgeons, with some relying on CT scans to determine healing. Progressive wrist range of
motion and strengthening is initiated following bony union.
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Outcomes
Distal pole scaphoid fractures are quite vascular and in the absence of substantial displacement can be
treated nonoperatively. Displaced scaphoid waist fractures are treated operatively, and the rate of union
is generally thought to be approximately 90%, though this depends upon surgical technique and patient
factors. Proximal pole fractures are managed with surgery, with some reports of union at 95%. 43
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Complications
Nonunion is the most important adverse outcome for scaphoid fracture. The overall incidence is
approximately 10%, but this rate may be elevated by delayed presentation, fracture comminution,
smoking, incomplete immobilization, or errors in surgical technique. 44 Because of the retrograde nature
of scaphoid vascularity, proximal pole fractures have an increased incidence of nonunion and avascular
necrosis.
The shortening and collapse of the scaphoid is manifested with flexion of the distal fragment and
proximal scaphoid extension. When not corrected, a predictable pattern of degenerative changes known
as scaphoid nonunion advanced collapse arthritis occurs.
A detailed classification system and complex treatment algorithms have been developed for treatment of
scaphoid nonunion. 45 Treatment principles for scaphoid waist nonunion include debridement and
reduction of the fracture if necessary, rigid fixation, and bone grafting to restore the native shape and
length of the scaphoid and induce osteogenesis. When nonunion is present in the absence of scaphoid
flexion, screw fixation and autogenous distal radius cancellous bone grafting can be performed via a
dorsal or volar approach (Figure 75.12). When a humpback deformity is present, a volar approach is
recommended such that the scaphoid can be extended and then held in alignment with corticocancellous
autogenous bone graft. 45
FIGURE 75.12 A. This patient presented with subacute wrist pain and radiographs demonstrated a scaphoid waist nonunion.
B, C. This was treated with debridement of the nonunion, cancellous bone grafting from the distal radius, and stabilization with
a headless compression screw via a volar approach.
An alternative to nonvascularized bone grafting is the use of pedicled or free vascularized bone flaps. A
variety of these flaps have been applied to nonunions when decreased vascularity of the proximal
fragment is suspected, and to those that have been recalcitrant to treatment with nonvascularized
autograft. In theory, by bringing new blood supply to the fracture site these flaps can aid in the healing of
a hypovascular fracture site. The 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) flap was the
first to be described, and several additional pedicled flaps from the dorsal and volar distal radius are
available. 46 These are limited by their small size and diminutive vascular pedicles. As an alternative, the
medial femoral condyle free flap has been popularized as a robust and reliable source of vascularized
bone for treatment of scaphoid waist nonunion. 47
In cases of proximal pole nonunion with avascular necrosis, the fragment may be too small or sclerotic to
allow intercalary bone grafting and fixation of the scaphoid. When this proximal fragment is
unsalvageable in a young patient, replacement of the entire proximal pole including the proximal
articular surface may be indicated. Options include nonvascularized osteochondral rib graft and a
vascularized free medial femoral trochlea osteochondral free flap 48 (Figure 75.13). In patients who are
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older and have low functional demand and in those who have developed arthritis of the radioscaphoid
joint or irreducible flexion of the distal scaphoid fragment, salvage options such as proximal row
carpectomy or limited intercarpal fusion are recommended.
FIGURE 75.13 In cases of proximal pole nonunion with avascular necrosis, the fragment may be too small or sclerotic to allow
intercalary bone grafting and fixation of the scaphoid. In this case, the proximal pole can be entirely resected (A), and the
scaphoid reconstructed with a medial femoral trochlea osteocartilaginous free flap harvested from the knee (C). Fixation of the
osteocartilaginous flap is achieved using a cannulated headless compression screw (B).
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Other Carpal Fractures
Triquetral Fractures
The triquetrum is the second most common carpal fracture. Dorsal rim fractures result from hyperflexion
and radial deviation resulting in avulsion of the dorsal radiocarpal and dorsal intercarpal ligaments with
a cortical fragment of the triquetrum. Most injuries can be treated with 3 to 6 weeks of immobilization;
however, large fragments may require surgical fixation. In dorsal rim fractures with associated
lunotriquetral ligament avulsion and resultant instability, the fragment can be ignored and the joint
simply pinned. 49 Triquetral body fractures reflect a high-energy mechanism and are often associated with
other pathology such as a greater arc perilunate dislocation. Displaced body fractures and those
associated with carpal instability patterns require surgical treatment.
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Hamate Fractures
Hook of Hamate
Two patterns of hamate fracture present with relative frequency: fractures of the hook and
hamatometacarpal fracture-dislocations. The hook of the hamate may be injured by compressive trauma
during stick-and-ball sports or by avulsion at its attachment to the transverse carpal ligament. This injury
may be associated with weak or painful grip due to the hook’s role as a pulley for the ring and small
flexor digitorum profundus tendons, or with ulnar nerve symptoms due to irritation of the adjacent
motor branch. Advanced imaging with CT scan or MRI may be required for diagnosis. Treatment of acute
hook fractures is 6 to 12 weeks of immobilization. 49 Established symptomatic nonunions are treated with
excision of the hook fragment.
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Hamatometacarpal Fracture-Dislocation
An axial load applied to the fourth and fifth metacarpals may result in fracture of metacarpal base,
extending through the carpometacarpal joint to include the dorsal hamate. The presence of a
hamatometacarpal fracture-dislocation can easily be missed on a standard radiographic series, and
clinical suspicion should prompt a pronated oblique film or CT scan. Treatment for these injuries may
include closed immobilization, percutaneous pinning of the carpometacarpal joints, or open reduction
and internal fixation. 50
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Questions
1. A 45-year-old woman presents to the emergency department with snuffbox and distal tubercle
tenderness 2 hours after a bicycle accident. She is insistent upon avoiding surgery. A favorable
outcome utilizing immobilization without operative intervention is most likely if her X-ray reveals
scaphoid fracture of which type?
a. Incomplete waist fracture
b. Nondisplaced proximal pole fracture
c. Nondisplaced proximal pole fracture with sclerosis
d. Displaced distal tubercle fracture
2. Verification that a VLP has been placed upon the distal radius in a position that is unlikely to cause
flexor tendon irritation or rupture can be best obtained using which plain radiographic view?
a. PA
b. Lateral
c. Oblique
d. Carpal tunnel view
3. Which clinical factor has not been implicated as a risk factor for radius fracture displacement after
initial closed reduction and plaster immobilization?
a. Dorsal comminution
b. Age over 60
c. Associated fracture of the ulna
d. Volar tilt of 10°
4. Dorsal bridge plating of a distal radius fracture should be strongly considered for initial
management of which patient?
a. 35-year-old woman with left closed intraarticular, comminuted distal radius fracture and
bilateral operative femur fractures
b. 95-year-old male with a right intraarticular distal radius fracture characterized by 5° of dorsal
angulation, ulnar neutral variance, and 1 mm of articular step-off
c. 25-year-old male pitcher with depressed fracture of the volar lunate facet
d. 45-year-old woman with a heavily comminuted metadiaphyseal fracture of the left distal
radius and ipsilateral segmental fractures of the second through fifth metacarpals
5. To what is the high risk of nonunion after treatment of a proximal pole scaphoid fracture
attributable?
a. The anterograde nature of the primary blood supply to the scaphoid, which enters volarly
b. The retrograde nature of the scaphoid’s blood supply, which enters volarly
c. The anterograde nature of the scaphoid’s blood supply, which enters dorsally
d. The retrograde nature of the scaphoid’s blood supply, which enters dorsally
6. A 23-year-old woman comes in to the emergency department after falling off her snowboard onto
an outstretched left hand. Physical examination demonstrates tenderness in the anatomic snuffbox.
Initial PA, lateral, and oblique plain radiographs of the wrist demonstrate no fracture. What
additional imaging is most sensitive and specific for detection of an acute scaphoid fracture?
a. Immediate MRI
b. Immediate CT scan
c. Immobilization and follow-up plain radiography in 2 weeks
d. Immobilization and follow-up plan radiography in 2 days
1. Answer: a. The modified Herbert classification scheme divides scaphoid fractures into three major
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groups: stable, unstable, and nonacute. Of the types listed above, only incomplete waist is a stable
type of fracture. As such, immobilization in a thumb spica cast for up to 12 weeks will likely result in
fracture union. Proximal pole fractures are at high risk for nonunion and avascular necrosis, and
generally fracture of the proximal pole is considered an indication for operative fixation in order to
reduce this risk. Avascular necrosis of the proximal pole occurs with a fracture that is subacute or
chronic condition and may be identified following a new acute injury. However, given that acute
scaphoid fractures can be easily missed, delayed detection at the time of reinjury symptom
exacerbation, or radiographic examination for an unrelated complaint is not uncommon.
Nonoperative treatment of a proximal pole nonunion is not recommended. Displaced scaphoid
fractures, regardless of the anatomical location, are not amenable to nonoperative treatment.
2. Answer: b. A VLP should be placed distal enough that all articular fragments are stabilized by
locking screws/pegs supporting the subchondral bone. However, placing the plate too distal leads to
volar prominence of the distal edge of the plate putting the flexor tendons at risk for irritation or
attritional rupture. As such, when possible, a VLP should be placed be positioned proximal enough
that it lies entirely volar to the volar rim of the distal radius. The proximodistal position of the plate
and the volar/dorsal relationship between plate and volar rim are best visualized on the lateral
projection. Although proximodistal placement of the plate can be assessed to some degree on the PA,
oblique views, the volar rim is easily distinguishable only on the lateral. The carpal tunnel view is
not applicable to distal radius fractures, but can be used to visualize hook of hamate, pisiform, and
trapezium fractures.
3. Answer: d. In a landmark 1989 study, Lafontaine et al demonstrated five clinical/radiographic
predictors of distal radius fracture displacement after initial closed reduction and immobilization.
These were initial dorsal angulation greater than 20°, dorsal comminution, radiocarpal intraarticular
involvement, associated fracture of the ulna, and age greater than 60 years. In a larger 2006 study,
Mackenney et al found that the most important predictors of fracture instability were advanced age,
dorsal comminution, and the position of the fracture at presentation. Volar tilt of 10° is well within
the range of normal and would not be considered a marker of fracture instability.
4. Answer: a. A dorsal bridge plate is a long, straight implant which spans the distal radius and is
anchored into the radial shaft and second or third metacarpal. By unloading the radiocarpal joint and
maintaining distraction across the fracture, dorsal bridge plating can provide rigid stability and
maintain some degree of articular reduction via ligamentotaxis. Notably, this technique does not call
for direct open manipulation of fracture fragments. For this reason, it is useful for heavily
comminuted fractures wherein surgical exposure would result in unacceptable devascularization of
the fragments. Additionally, because this bridging technique protects the distal radius from any axial
loading, it is relatively indicated in polytraumatized patients who require early upper extremity
weight bearing to facilitate lower extremity rehabilitation or transfers.
5. Answer: d. Gelberman et al demonstrated that 70% to 80% of the intraosseous vascularity (and the
entire proximal pole) comes from the dorsal scaphoid branches of the radial artery, entering through
the dorsal ridge. These dorsal vessels enter the scaphoid distally and course in a retrograde direction
to supply the proximal pole of the scaphoid. A minor volar contribution comes from radial artery or
its superficial palmar branch, which gives off several volar scaphoid branches at the level of the
radioscaphoid joint, entering the bone at its distal tubercle.
6. Answer: a. Approximately 20% of patients with clinical suspicion for a scaphoid fracture and
negative initial plain radiographs have an occult fracture. For this reason, patients with negative
radiographs have traditionally been immobilized for 2 weeks and then sent for repeat plain
radiography seeking interval displacement or resorption. Disadvantages of this strategy include the
fact that is unnecessarily immobilizes many of patients and still fails to detect 9% of scaphoid
fractures. In an effort to avoid these disadvantages, immediate advanced imaging has gained
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popularity. MRI is the most sensitive commonly employed modality (97.2%), followed by CT
(90.7%).
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References
Karl, JW, Olson, PR, Rosenwasser, MP. The epidemiology of upper extremity fractures in the United States, 2009. J Orthop Trauma.
2015;29(8):e242-e244.
Swart, E, Tulipan, J, Rosenwasser, MP. How should the treatment costs of distal radius fractures be measured? Am J Orthop. 2017;46(1):E54-
E59.
Kleinman, WB. Stability of the distal radioulna joint: biomechanics, pathophysiology, physical diagnosis, and restoration of function what we
have learned in 25 years. J Hand Surg Am. 2007;32(7):1086-1106.
Pechlaner, S, Kathrein, A, Gabl, M, et al. Distal radius fractures and concomitant lesions. Experimental studies concerning the
pathomechanism. Handchir Mikrochir Plast Chir. 2002;34(3):150-157.
Shehovych, A, Salar, O, Meyer, C, Ford, DJ. Adult distal radius fractures classification systems: essential clinical knowledge or abstract
memory testing? Ann R Coll Surg Engl. 2016;98(8):525-531.
Ng, CY, McQueen, MM. What are the radiological predictors of functional outcome following fractures of the distal radius? J Bone Joint Surg
Br. 2011;93(2):145-150.
Goldfarb, CA, Yin, Y, Gilula, LA, et al. Wrist fractures: what the clinician wants to know. Radiology. 2001;219(1):11-28.
Medoff, RJ. Essential radiographic evaluation for distal radius fractures. Hand Clin. 2005;21(3):279-288.
Graham, T. Surgical correction of malunited fractures of the distal radius. J Am Acad Orthop Surg. 1997;5(5):270-281.
Lafontaine, M, Hardy, D, Delince, P. Stability assessment of distal radius fractures. Injury. 1989;20(4):208-210.This study examined 112 distal
radius fractures treated with closed reduction and plaster immobilization. Five criteria including dorsal angulation >20, dorsal comminution,
intraarticular radiocarpal fracture, associated ulnar fracture, and age exceeding 60 years were found to predict loss of reduction despite immobilization.
As a result, the authors recommended close radiological surveillance and possible early fixation of fractures with three or more of these risk factors.
Mackenney, PJ, McQueen, MM, Elton, R. Prediction of instability in distal radial fractures. J Bone Joint Surg Am. 2006;88A:1944-1951.Over 4000
distal radial fractures were prospectively assessed for early and late instability. Patient age, metaphyseal comminution of the fracture, and ulnar
variance, but not dorsal angluation were identified as the most consistent independent predictors of radiographic outcome. Formulas to predict the
radiographic outcome were constructed using these independent predictors, and can be used to inform surgical decision-making.
Agee, JM. Application of multiplanar ligamentotaxis to external fixation of distal radius fractures. Iowa Orthop J. 1994;14:31-37.
Fernandez, DL. Closed manipulation and casting of distal radius fractures. Hand Clin. 2005;21(3):307-316.
Trumble, TE, Wagner, W, Hanel, DP, et al. Intrafocal (Kapandji) pinning of distal radius fractures with and without external fixation. J Hand
Surg Am. 1998;23(3):381-394.
Chia, B, Catalano, LW, Glickel, SZ, et al. Percutaneous pinning of distal radius fractures: an anatomic study demonstrating the proximity of
K-wires to structures at risk. J Hand Surg Am. 2009;34(6):1014-1020.
Chaudhry, H, Kleinlugtenbelt, YV, Mundi, R, et al. Are volar locking plates superior to percutaneous k-wires for distal radius fractures? A
meta-analysis. Clin Orthop Relat Res. 2015;473(9):3017-3027.This is a metaanalysis of seven randomized controlled trials to determine whether
patients treated with volar locking plates achieved better function, wrist motion, radiographic outcomes, or fewer complications patients treated with K-
wires for dorsally displaced distal radius fractures. Patients treated with volar locking plates had slightly better early function, fewer superficial wound
infections, and similar radiographic outcomes as patient treated with K-wires. The clinical significance of these differences is questionable, and both
methods of fixation are still in use.
Orbay, JL, Fernandez, DL. Volar fixation for dorsally displaced fractures of the distal radius: a preliminary report. J Hand Surg Am.
2002;27(2):205-215.This clinical series marks the introduction of volar locking fixation for the treatment of distal radius fractures and is the first
documentation of outcomes using this technique. The authors conclude that this is a versatile technique with a favorable complication profile and is
applicable to many patterns of distal radius fracture.
Soong, M, Earp, BE, Bishop, G, et al. Volar locking plate implant prominence and flexor tendon rupture. J Bone Joint Surg Am. 2011;93A:328-
335.This study classified volar locking plates applied to the distal radius according to their degree of volar prominence on the lateral radiograph. The
authors conclude that there is an increased risk of flexor tendon rupture when plates are more prominent than the volar rim, corresponding to placement
beyond the watershed line.
Quadlbauer, S, Pezzei, C, Jurkowitsch, J, et al. Early rehabilitation of distal radius fractures stabilized by volar locking plate: a prospective
randomized pilot study. J Wrist Surg. 2017;6(2):102-112.
Dy, CJ, Wolfe, SW, Jupiter, JB, et al. Distal radius fractures: strategic alternatives to volar plate fixation. Instr Course Lect. 2014;63:27-37.
Azzi, AJ, Aldekhayel, S, Boehm, KS, Zadeh, T. Tendon rupture and tenosynovitis following internal fixation of distal radius fractures. Plast
Reconstr Surg. 2017;139(3):717e-724e.
Hanel, DP, Lu, TS, Weil, WM. Bridge plating of distal radius fractures. Clin Orthop Relat Res. 2006;445:91-99.
Sammer, DM, Chung, KC. Management of the distal radioulnar joint and ulnar styloid fracture. Hand Clin. 2012;28(2):199-206.
Hanel, DP, Jones, MD, Trumble, TE. Wrist fractures. Orthop Clin North Am. 2002;33(1):35-57.
Desai, MJ, Kamal, RN, Richard, MJ. Management of intercarpal ligament injuries associated with distal radius fractures. Hand Clin.
2015;31(3):409-416.
Placzek, JD, Boyer, MI, Gelberman, RH, et al. Nerve decompression for complex regional pain syndrome type II following upper extremity
surgery. J Hand Surg Am. 2005;30(1):69-74.
Mathews, AL, Chunk, KC. Management of complications of distal radius fractures. Hand Clin. 2015;31(2):205-215.
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Wall, LB, Brodt, MD, Silva, MJ, et al. The effects of screw length on stability of simulated osteoporotic distal radius fractures fixed with volar
locking plates. J Hand Surg Am. 2012;37(3):446-453.This biomechanical study investigated the effect of screw length upon the stability of distal
radius fractures fixed with volar locking fixation. The authors found that locked unicortical distal screws of at least 75% the AP length of the distal
radius produce construct stiffness similar to bicortical fixation. They concluded unicortical distal fixation using screws of adequate length does not
compromise construct integrity and should be entertained in cases of extraarticular distal radius fracture to avoid extensor tendon injury.
Slutsky, DJ, Herman, M. Rehabilitation of distal radius fractures: a biomechanical guide. Hand Clin. 2005;21(3):455-468.
Waljee, JF, Ladd, A, MacDermid, JC, et al. A unified approach to outcomes assessment for distal radius fractures. J Hand Surg Am.
2016;41(4):565-573.
Garala, K, Taub, NA, Dias, JJ. The epidemiology of fractures of the scaphoid: impact of age, gender, deprivation and seasonality. Bone Joint J.
2016;98B(5):654-659.
Freedman, DM, Botte, MJ, Gelberman, RH. Vascularity of the carpus. Clin Orthop Relat Res. 2001;(383):47-59.
Berg Ten, P, Drijkoningen, T, Strackee, S, Buijze, G. Classifications of acute scaphoid fractures: a systematic literature review. J Wrist Surg.
2016;05(02):152-159.
Filan, SL, Herbert, TJ. Herbert screw fixation of scaphoid fractures. J Bone Joint Surg Br. 1996;78(4):519-529.
Russe, O. Fracture of the carpal navicular: diagnosis, nonoperative treatment, and operative treatment. J Bone Joint Surg Am. 1960;42A:759-
768.
Yin, ZG, Zhang, JB, Gong, KT. Cost-effectiveness of diagnostic strategies for suspected scaphoid fractures. J Orthop Trauma. 2015;29(8):e245-
e252.
Cooney, WP, Dobyns, JH, Linscheid, RL. Fractures of the scaphoid: a rational approach to management. Clin Orthop Relat Res. 1980;(149):90-
97.
Ram, AN, Chung, KC. Evidence-based management of acute nondisplaced scaphoid waist fractures. J Hand Surg Am. 2009;34(4):735-738.
Buijze, GA, Goslings, JC, Rhemrev, SJ, et al. Cast immobilization with and without immobilization of the thumb for nondisplaced and
minimally displaced scaphoid waist fractures: a multicenter, randomized, controlled trial. J Hand Surg Am. 2014;39(4):621-627.
Herbert, TJ, Fisher, WE. Management of the fractured scaphoid using a new bone screw. J Bone Joint Surg Br. 1984;66B:114-123.This clinical
series marks the introduction of the headless compression screw for the treatment of scaphoid fractures and is the first documentation of outcomes using
this technique. The authors document high rates of fracture union in primary and secondary cases and conclude that this device has wide applicability
in the treatment of scaphoid fractures. Modern scaphoid (and other) fixation is based upon a cannulated modification of this original headless
compression screw.
Whipple, TL. Stabilization of the fractured scaphoid under arthroscopic control. Orthop Clin North Am. 1995;26(4):749-754.
Merrell, G, Slade, J. Technique for percutaneous fixation of displaced and nondisplaced acute scaphoid fractures and select nonunions. J
Hand Surg Am. 2008;33(6):966-973.
Suh, N, Grewal, R. Controversies and best practices for acute scaphoid fracture management. J Hand Surg Eur Vol. 2018;43:4-12.This review
article represents a current and complete collation of the evidence surrounding the diagnosis, management, and outcomes of acute scaphoid fractures.
Evidence-based recommendations are included with citation of the supporting literature.
Pinder, RM, Brkljac, M, Rix, L, et al. Treatment of scaphoid nonunion: a systematic review of the existing evidence. J Hand Surg Am.
2015;40(9):1797-1805.
Janowski, J, Coady, C, Catalano, LW III. Scaphoid fractures: nonunion and malunion. J Hand Surg Am. 2016;41:1087-1092.
Rizzo, M, Moran, S. Vascularized bone grafts and their applications in the treatment of carpal pathology. Semin Plast Surg. 2008;22(3):213-227.
Jones, DB Jr, Moran, SL, Bishop, AT, Shin, AY. Free-vascularized medial femoral condyle bone transfer in the treatment of scaphoid
nonunions. Plast Reconstr Surg. 2010;125(4):1176-1184.
Higgins, J, Burger, H. Proximal scaphoid arthroplasty using the medial femoral trochlea flap. J Wrist Surg. 2013;2(3):228-233.
Pan, T, Lögters, TT, Windolf, J, Kaufmann, R. Uncommon carpal fractures. Eur J Trauma Emerg Surg. 2016;42(1):15-27.
Kim, JK. A novel hamatometacarpal fracture-dislocation classification system based on CT scan. Injury. 2012;43(7):1112-1117.
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C H A P T E R 7 6
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Flexor Tendon Repair and Reconstruction
Xuan Qiu and Kevin C. Chung
Key Points
Complete flexor tendon lacerations should be repaired early (preferably within 7 days of injury).
Flexor tendon undergoes both intrinsic and extrinsic healing after repair.
At least four-strand core sutures placed 1 cm from the tendon ends should be used to repair flexor
tendon lacerations.
Epitendinous sutures augment flexor tendon repair strength.
Early protective motion improves the functional outcome of flexor tendon repair.
Shortening of a single digit flexor digitorum profundus tendon more than 1 cm should be avoided to
prevent the quadriga effect.
Finger flexion is powered by the actions of extrinsic and intrinsic muscles of the hand across multiple
joints. Flexor tendon injuries result in loss of finger flexion and impair power grip. These injuries are
often a result of penetrating trauma to the volar aspect of the fingers, palm, wrist, or forearm. Avulsion of
flexor digitorum profundus insertion at the base of the distal phalanx, or degenerative flexor tendon tears
in systemic inflammatory conditions such as rheumatoid arthritis, can also result in loss of finger flexion.
Management of flexor tendon injuries can be challenging, especially those within the fibrous digital
sheath, because of the tendency for peritendinous adhesion formation after surgery, which discourages
smooth gliding and prevents normal range of motion of the fingers. The evolution of treatment for flexor
tendon injuries has exemplified how clinical practice has been driven by our understanding of the
molecular biology and biomechanics of tendon healing from basic science and clinical research to
ultimately overcome the challenges in managing these conditions. Recent advances in surgical
techniques, suture design, and postsurgical rehabilitation protocols have made flexor tendon repair and
reconstruction more satisfactory to both the patient and surgeon.
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Anatomy
There are nine flexor tendons in the hand. The flexor pollicis longus (FPL) controls thumb flexion; the
flexor digitorum profundus (four FDP) and flexor digitorum superficialis (four FDS) control finger
flexions. The flexor tendon muscles originate from the volar proximal to mid forearm, and distally their
tendons enter the carpal tunnel before continuing to insert on the palmar aspect of the fingers. The
contraction of the flexor tendon muscles leads to flexion of the fingers to make a composite fist; the distal
tendon insertions determine the level of flexion (Table 76.1).
TABLE 76.1
Flexor Tendon Muscles
Muscles
Description
Flexor pollicis longus
(FPL)
Origin: radial shaft and interosseous membrane
Insertion: base of the distal phalanx of the thumb
Innervation: anterior interosseous branch of the median nerve (AIN)
Action: flexion of the interphalangeal (IP) joint of the thumb
Flexor digitorum
profundus (FDP)
Origin: proximal ulna and the interosseous membrane
Insertion: base of the distal phalanx of index, middle, ring, and small fingers
Innervation: AIN for the index and middle fingers; ulnar nerve for the ring and small fingers
Action: flexion of the distal interphalangeal (DIP) joint
Flexor digitorum
superficialis (FDS)
Origin: ulnar head from medial humeral epicondyle, the ulnar collateral ligament, and the coronoid
process; radial head from proximal radius
Insertion: palmar aspect of the middle phalanx
Innervation: median nerve
Action: flexion of the proximal interphalangeal (PIP) joints
Unlike the FDP tendons that spread to the fingers in the same coronal plane at the wrist and forearm, the
FDS tendons are stacked in two layers, with the more superficial tendons inserting onto the middle and
ring fingers, and the deeper tendons inserting onto the index and small fingers, respectively.
Additionally, each FDS tendon divides into two slips, radial and ulnar, to wrap around the FDP tendon to
continue distally on the dorsal aspect of the FDP tendon. They reunite at the Camper chiasm before
dividing again into two slips to insert onto the palmar aspect of the middle phalanx (Figure 76.1).
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FIGURE 76.1 Anatomy of flexor tendons.
(Reproduced with permission from Machol, JA IV, Chen, NC, Eberlin, KR. Acute repair of flexor tendon injuries. In: Chung, KC , ed. Operative Techniques in
Plastic Surgery. Philadelphia, PA: Wolters Kluwer; 2019. Part 6, Figure 37-1a.)
The FDS and FDP tendons within the flexor tendon sheath receive nutritional supply and eliminate
wastes by two ways: vascular perfusion and synovial diffusion. The direct arterial supply to the flexor
tendons comes from the well-developed vincular system, which takes off the common digital arteries and
continues to the dorsal aspect of the tendon (Figure 76.2). The palmar aspect of the tendon is relatively
avascular, and the paratenon promotes material exchange by means of diffusion. 1
FIGURE 76.2 Vascularity of flexor tendons.
The flexor tendons are covered by a thin layer of fibroblasts known as the epitenon, which is surrounded
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by a synovial sheath. The membranous inner component of the sheath provides a smooth gliding surface
in addition to secreting synovial fluid rich in hyaluronic acid, 2 which provides both lubrication and
nutrition. The outer component of the sheath is the retinaculum, which condenses into fibrous bands of
tissue that forms a fibro-osseous tunnel on the palmar surface of the fingers to restrain the flexor tendons
close to the adjacent bone or joint. These fibrous bands are known as the pulleys (Figure 76.3A). They are
named based on the orientation of their fibers, including annular (A) and cruciate (C) pulleys. The thumb
has its own pulley system, which includes two annular pulleys, A1 and A2, separated by an oblique
pulley which is the most important one in the thumb (Figure 76.3B). 3
FIGURE 76.3 Pulley systems of the fingers (A) and thumb (B).
(A. Reproduced with permission from Machol, JA IV, Chen, NC, Eberlin, KR. Acute repair of flexor tendon injuries. In: Chung, KC , ed. Operative Techniques
in Plastic Surgery. Philadelphia, PA: Wolters Kluwer; 2019. Part 6, Figure 37-1B.)
In the fingers, the A pulleys are numbered A1 through A5, and the C pulleys are numbered C1 through
C3. The A2 and A4 pulleys originate from the periosteum of the proximal and middle phalanx,
respectively. They are the most important pulleys in maintaining grip power and preventing
bowstringing of the flexor tendons during active finger flexion. The A1, A3, and A5 pulleys arise from the
volar plate of the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal
(DIP) joints, respectively. They prevent bowstringing of the flexor tendons across these joints during
active finger flexion. The A1 pulley is the most commonly affected pulley in trigger fingers and usually
divided during trigger finger release. The more flexible cruciate (C1–C3) pulleys are located inbetween
the annular pulleys and in close proximity with the joints. They function to accommodate full flexion and
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extension of the joints without significant collapse or expansion of the adjacent annular pulleys during
finger motion.
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Clinical Evaluation
Evaluation of patients with possible flexor tendon injuries should begin with a detailed history to
determine the mechanism and timing of the injury. The position of the hand and fingers at the time of
injury, and the presence of a soft tissue mass on physical examination, can often provide a clue on where
the proximal end of the lacerated tendon is located. The location and extent of skin injuries should be
carefully assessed. Any notable deformity suggests underlying bone or ligamentous injury, which may
require manipulation or reduction. Plain radiographs can help confirm bone or joint abnormalities as well
as the presence of a foreign body. Local anesthetics or sedation should be held until after a careful
neurovascular examination. Loss of sensation to light touch and two-point discrimination in a digital
nerve distribution suggest nerve transection. Delayed capillary refill or an abnormal digital Allen test
suggests a digital artery laceration, which can also be confirmed with a Doppler.
Flexor tendon injury can lead to loss of the active finger flexion, normal finger cascade, resting flexor tone
resulting in extension posturing, and tenodesis effect. The tenodesis effect is the phenomenon of finger
flexion when the wrist is passively extended. Individual fingers should be examined to determine the
integrity of the FDS and the FDP tendons. Active finger flexion at the PIP joint while adjacent digits are
held down in full extension at the MCP, PIP, and DIP joints indicates that the FDS tendon is intact. Active
finger flexion at the DIP joint while the finger is held in full extension at the middle phalanx indicates that
the FDP tendon is intact (Figure 76.4). Similarly in the thumb, active flexion at the IP joint indicates that
the FPL tendon is intact. Partial tendon injury can manifest as pain with active finger flexion. These
injuries are either repaired if the laceration involves more than 50% of the cross-sectional area or debrided
if the involvement is less than 50% of the cross-sectional area to minimize catching during finger range of
motion. 4
FIGURE 76.4 Physical examination of flexor tendons. A. FDS. B. FDP.
Flexor tendon injuries are classified into five anatomic zones (zone 1 through zone 5) based on location
(Figure 76.5). 5 Zone 1 is the area distal to the insertion of the FDS tendon, i.e., only involving the FDP
tendon. Zone 2 describes the area within the flexor tendon sheath distal to the A1 pulley but proximal to
the FDS insertion; therefore, injuries within this zone can potentially compromise both the FDS and the
FDP tendons. Historically Zone 2 injuries were challenging to manage because of the complex anatomy
and the high likelihood of complications after repair, earning Zone 2 the name of no man’s land. 6 Zone 3
describes the area in the palm distal to the carpal tunnel. Zone 4 is the area within the carpal tunnel. Zone
4 tendon injury is rather uncommon because the overlying trapezium and hamate prominence shield the
tendons in this zone from laceration. Zone 5 is the area from the proximal muscle-tendon junction to the
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carpal tunnel.
FIGURE 76.5 Flexor tendon zones of injury.
(Reproduced with permission from Wiesel, SM. Operative Techniques in Orthopaedic Surgery. Philadelphia, PA: Wolters Kluwer Health/Lippincott Williams &
Wilkins; 2010. Figure 56-1a.)
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Management
The treatment goal of a flexor tendon injury is to restore a strong and smooth construct such that a
rehabilitation protocol can promote tendon gliding and minimize peritendinous adhesion, and ultimately
restore normal motion of the finger. Sometimes this requires partial excision of the FDS tendon to
decrease the repair bulk, 7,8 or partial release of the adjacent pulleys. 9 Any fresh open wounds in the hand
noted during initial examination should be thoroughly irrigated with sterile saline. A dose of first-
generation cephalosporin should be administered if there is no contraindication. Tetanus prophylaxis
should also be provided to the patient if not up-to-date.
In the setting of vascular compromise to the digit with concomitant flexor tendon injury, emergency
wound exploration and microvascular repair or reconstruction to restore digital perfusion are indicated,
and the lacerated flexor tendons can be repaired at the same time. Otherwise definitive repair of flexor
tendon laceration can be scheduled within 7 days of the injury. The injured finger and the wrist should be
splinted in slight flexion to prevent further proximal migration of the proximal end of the lacerated
tendon. Beyond 6 weeks, the primary repair of flexor tendon is unlikely to succeed because of myostatic
contracture of the lacerated tendon and swelling of the tendon ends that do not permit tendons to be
retrieved through the pulleys. In the cases of delayed presentation, the surgeon should be prepared for
conducting two-stage tendon reconstruction or primarily tendon grafting if the wound bed is not too
scarred.
Early animal studies suggested that tendon healing required adhesion formation, characterized by
infiltration of fibroblasts and capillary buds, which came from the surrounding synovial sheath. 10-12
However, later experiments demonstrated the alternative intrinsic tendon healing without adhesion
formation. This was illustrated in an elegant study in which repaired tendon bathed in the synovial fluid
of a rabbit knee healed without extrinsic blood supply. 13 This intrinsic tendon healing undergoes three
phases of wound healing: inflammation, neovascularization, and remodeling. The earliest stage is
characterized by an increase in the inflammatory cells including macrophages 14 and their mediators such
as interleukins and matrix metalloproteinases. 15 During tendon healing, neovascularization occurs to
bring necessary nutrients for tendon repair and healing, 16 with concomitant early rise of vascular
endothelial growth factor 17 and integrin family of cell adhesion receptors. 18 Eventually new collagen
formation and reorientation of the collagen fibers restore the tendon morphology and synovial sheath
anatomy. 19
Several factors affect the quality of the flexor tendon repair. Core sutures are those that traverse the main
substance of the tendon for coaptation of the repair site. There are different techniques of core suturing,
from the classic two-stranded Tajima to the simple four-stranded Strickland and cruciate, and to the more
complex multi-stranded Modified Becker/Massachusetts General Hospital (MGH) suture repair (Figure
76.6A–C). Biomechanical studies have shown that increasing the suture caliber can increase the tensile
strength at the repair site. 20 Similarly, an increased number of core strands also increases repair strength
21 (Table 76.2). 22 Of the two parameters, the core strand number is more important than suture caliber in
terms of increasing repair site strength. 23 Based on these data, a nonabsorbable suture, 3-0 to 4-0
depending on the size of the tendon to be repaired, should be placed at 1 cm from the cut edges to
provide at least 4-strand core sutures across the repair site to ensure the approximation of the tendon
ends for optimal healing. 24 Moreover, locking core suture loops are stronger than grasping loops, 25 and
the location of the core suture knot, inside or outside of the repair site, has not been shown to affect the
repair site strength. 26
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