PROCEDURE 90
Fractional Lengthening of Flexor Tendons and Flexor Digitorum Superficialis to Flexor Digitorum Profundus Transfer Matthew Brown, Jennifer F. Waljee, and Kevin C. Chung Indications • Patients with a flexed wrist position and digital flexor tendon tightness • Fractional lengthening is offered to patients who have voluntary control of their fingers, but who are unable to passively extend their fingers with the wrist in a neutral position. This procedure can improve a deformity while maintaining function, if present. Presented is a patient who has active finger extension but is unable to fully extend the fingers because of a flexion contracture (Fig. 90.1A and B). • Flexor digitorum superficialis (FDS) to flexor digitorum profundus (FDP) transfer is for significant contracture, which is defined as the inability to extend the fingers even if the wrist is flexed. Shown is a patient who has severe flexor tendon contracture with inability to passively extend the fingers from the palm even with maximal wrist flexion. These patients typically do not have voluntary control of the fingers and the hands are not functional (Fig. 90.2A and B). • In the nonfunctional hand, the procedures are indicated to assist with hygiene difficulty. Illustrated is a patient with severe flexion contracture that precluded normal hygiene. The long fingernails had not been clipped, causing penetrating wounds of the palm (Fig. 90.2C). • Greater tendon lengthening is associated with a more weakened muscle function.
Clinical Examination • Wrist flexion may be caused by the flexor carpi ulnaris (FCU), or less commonly, the flexor carpi radialis (FCR) or palmaris longus (PL). Passive flexion and extension of the wrist is evaluated. These flexors may need to be addressed in addition to the finger flexor tendons. • Digital flexor tightness can be assessed with Volkmann’s test. The digits are extended with the wrist flexed. The wrist is then slowly extended while holding the fingers in extension. Wrist extension less than neutral requires surgical intervention (Fig. 90.3A and B). • The wrist is flexed to assess for fixed joint contractures in the fingers. Wrist flexion places slack on the FDP and superficialis tendons. The joints are flexed and extended to assess passive mobility of the fingers to rule out fixed joint contractures. If the joints are fixed in all wrist positions, joint contracture is another concern.
A
Imaging • X-rays of the wrist and hand can be helpful to examine arthrosis or primary joint contracture.
Surgical Anatomy • The volar forearm anatomy is critical to this procedure (Fig. 90.4). • Superficially the PL, FCR, FCU, FDS are encountered. • The deeper muscles and tendons include the FDP, flexor pollicis longus (FPL), and pronator quadratus (PQ).
B FIG. 90.1 A-B
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A
B
C FIG. 90.2 A-C
A
Palmaris Ulnar nerve and artery FDS FCR
Median nerve
B FIG. 90.3 A-B
FIG. 90.4 FCR, flexor carpi radialis; FDS, flexor digitorum superficialis.
PROCEDURE 90 Fractional Lengthening of Flexor Tendons and FDS to FDP Transfer
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• Proximally in the forearm, the median nerve travels between the FDS and FDP before emerging between the FDS and FPL distally. • The palmar cutaneous branch of the median nerve divides from the median nerve 5 cm proximal to the wrist crease and courses ulnar to the FCR. • The ulnar nerve and artery lie just radial and deep to the FCU.
Positioning • The patient is placed supine with the arm extended and the forearm supinated to expose the volar surface.
Exposures • A 5- to 7-cm longitudinal incision is made between the middle and distal thirds of the volar forearm. This incision is extended distally to the wrist if performing an FDS to FDP transfer (Fig. 90.5). • Division of the volar forearm fascia exposes the underlying muscles and tendons (Fig. 90.6).
FRACTIONAL LENGTHENING OF FLEXOR TENDONS Procedure Step 1: Tenotomy Design • The musculotendinous junction of the flexor tendon is identified. • Two tenotomies are designed 1 cm apart over the musculotendinous interval (Fig. 90.7).
Step 2: Fractional Cut • A transverse tenotomy is performed, cutting the tendon but preserving the underlying muscle fibers (Fig. 90.8).
FIG. 90.5
EXPOSURES PEARLS
The skin incision is designed in such a way that it could be extended distally to release the carpal tunnel, if this is being performed simultaneously. STEP 1 PEARLS
The distal tenotomy is made at least 2 cm proximal to the most distal aspect of the junction. This will ensure the muscular attachments to the tendon are kept intact.
STEP 1 PITFALLS
Identify the median nerve before dividing any tendon. It can be difficult to differentiate the median nerve from the finger flexor tendons, especially under tourniquet application.
FIG. 90.6
Musculotendinous junction
FIG. 90.7
FIG. 90.8
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PROCEDURE 90 Fractional Lengthening of Flexor Tendons and FDS to FDP Transfer
STEP 2 PITFALLS
Avoid hyperextension of the fingers or wrist. This may damage or avulse the muscular attachments.
• Gentle wrist extension is applied when lengthening the wrist flexors and gentle finger extension is applied for finger flexors. The tenotomy site will expand, but the muscle fibers remain in continuity (Fig. 90.9). • A second tenotomy is made 1 cm proximal to the first tenotomy if more lengthening is necessary.
Step 3: Closure • The incision is closed with interrupted deep absorbable sutures and a running absorbable monofilament suture. • The arm is immobilized in a plaster splint with the wrist in neutral and the fingers extended as much as possible for at least 2 weeks to maintain the length of the muscle-tendon units. After 2 weeks, the patient can initiate stretching exercises to regain function.
SUPERFICIALIS TO PROFUNDUS TRANSFER (STP TRANSFER)
STEP 1 PEARLS
Procedure
• Label the tendons as they are cut. This simplifies transfer to the corresponding FDP tendon in a later step. • The PL can be divided if it is contributing to wrist flexion contracture (Fig. 90.12).
Step 1: Division of the FDS
STEP 1 PITFALLS
The median nerve is visualized throughout the procedure to ensure it is not cut.
• After exposure, the FDS and FDP tendons are identified and differentiated from the median nerve (Fig. 90.10). • The four FDS tendons are individually identified and labeled. • The wrist is flexed and the FDS tendons are transected as distally as possible. • The cut FDS tendons are retracted and the musculotendinous junction of the FDP is located (Fig. 90.11).
FDS
Median nerve Palmar cutaneous branch FCR
FIG. 90.9
FDP musculotendinous junction
FIG. 90.10 FCR, flexor carpi radialis; FDS, flexor digitorum superficialis.
FDS
FIG. 90.11 FDP, flexor digitorum profundus; FDS, flexor digitorum superficialis.
FIG. 90.12
PROCEDURE 90 Fractional Lengthening of Flexor Tendons and FDS to FDP Transfer
Step 2: Division of the FDP • The individual FDP tendons are identified, labeled, and divided just before the musculotendinous junction (Fig. 90.13). • The fingers are fully extended to ensure release. The initial overlap of the FDS and FDP tendons will reduce as the contracture is corrected (Fig. 90.14).
Step 3: FDS-to-FDP Transfer • The proximal cut end of the superficialis tendon to each finger is then sewn to the distal cut end of the corresponding flexor profundus tendon in a Pulvertaft weave fashion. The transfer is secured with interrupted 3-0 braided nonabsorbable suture (Fig. 90.15). • With this configuration, the FDP tendons to the fingers are now attached the FDS muscles in the forearm (Fig. 90.16). • The repair tension is set with the wrist in neutral and digits flexed 45 degrees at the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints (Fig. 90.17A and B).
Step 4: Closure
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STEP 2 PEARLS
• Some surgeons favor suturing all of the FDS tendons or all of the FDP tendons together to create a single unit to simplify transfer. • Individual tendon transfer enables tension to be set for each finger independently and achieves a stronger Pulvertaft weave repair. STEP 2 PITFALLS
In many cases, severely contracted fingers may be difficult to completely clean at the start of the operation. After release of the contracture, the fingers and palm are cleansed a second time with Betadine to reduce the chance of infection. STEP 3 PEARLS
With the wrist in neutral, the fingers should passively fully extend.
• The incision is closed with interrupted deep absorbable suture and 4-0 nylon suture superficially. • The wrist is immobilized in neutral with the MCP joints flexed at 60 degrees and the fingers in full extension.
FIG. 90.13
FIG. 90.14
FIG. 90.15
FIG. 90.16
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PROCEDURE 90 Fractional Lengthening of Flexor Tendons and FDS to FDP Transfer
Before surgery, during active extension
A After surgery, during active extension
A
B
B
FIG. 90.17 A-B
FIG. 90.18 A-B
Postoperative Care and Expected Outcomes Fractional Lengthening Only • Dressings are removed at 2 weeks and protected range-of-motion therapy is started. • For 4 weeks patients use a protective removable wrist splint when not performing therapy. • The range of motion may not change significantly, but the posture and position of the fingers can provide more function for the patient (Fig. 90.18A and B).
Superficialis to Profundus Transfer • Dressings are removed within 1 week. • A removable splint with 20 degrees of wrist extension and 20 degrees MCP flexion is used continuously for 4 weeks and then transferred to night splinting for as long as tolerated. • Active motion therapy is typically not pursued because most hands are nonfunctional. • Excellent results regarding hygiene improvement have been observed in reported case series. See Video 90.1, Fractional Lengthening of Flexor Tendons, on ExpertConsult.com.
EVIDENCE Heijnen C, Franken R, Bevaart B, Meijer J. Long-term outcome of superficialis-to-profundus tendon transfer in patients with clenched fist due to spastic hemiplegia. Disabil Rehabil 2008;30:675–8. This is a retrospective review of six patients who underwent STP transfer with spastic hemiplegia after stroke. Patients were a mean age of 54 years old and 10 years after stroke. The indication was hygienic problems in all patients and 3 patients also reported pain. Mean follow-up was 19 months. Postoperatively, all hands could be passively opened and mean resting position of the MCP was 60 to 90 degrees. All patients were satisfied with their choice to have surgery. Keenan M, Korchek J, Botte M, Smith C, Garland D. Results of transfer of the flexor digitorum superficialis tendons to the flexor digitorum profundus tendons in adults with acquired spasticity of the hand. J Bone Joint Surg Am 1987;69:1127–32.
PROCEDURE 90 Fractional Lengthening of Flexor Tendons and FDS to FDP Transfer This is retrospective review of 31 patients (34 hands) treated with STP transfer. Patients were examined a mean of 50 months postoperatively. The transfer was performed en mass from FDS to FDP. All of the patients had a clenched-fist deformity preoperatively, with severe hygienic problems of the palmar skin and no active function of the hand. Postoperatively, all of the hands were in an open position, which allowed for good hygiene of the palmar surface. Complications included minor wound infections in three patients. Keenan M, Abrams R, Garland D, Waters R. Results of fractional lengthening of the finger flexors in adults with upper extremity spasticity. J Hand Surg Am 1987;12:575–81. This is a retrospective review of the results of fractional lengthening of the finger flexors in 27 patients with upper extremity flexor spasticity with mean follow-up time of 33 months. Patients were divided preoperatively into those with potentially functional hands (n = 22) and those who were nonfunctional (n = 5) based on the presence of motor control and hand sensibility. Postoperatively, all five nonfunctional hands, which lacked any motor control, improved in posture, and the hygiene problems resolved. Twenty of the 22 patients with potentially functional hands (91%) improved their spastic hand function score, with a mean of 3.7 points. Two patients (9%) decreased their spastic hand function score as a result of overlengthening of the finger flexors, with loss of grip strength.
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