Flexor Tendon Repair

Michael S. Bednar

Indications

1. Flexor tendon laceration in zones I through V (Fig. 18–1)

2. Flexor digitorum profundus avulsion

3. Flexor tendon rupture

Contraindications

1. Flexor tendon lacerations or avulsions greater than 7 to 10 days old in which a myostatic contracture of the muscle has developed

2. Crush injury with tendon loss (requires primary or two-stage grafting depending on the status of skin, pulleys, and bones)

3. Infected wound (need to debride prior to placing sutures in tendon)

Preoperative Preparation

1. Document status of preoperative neurovascular examination.

2. If a delayed primary repair is performed (within 10 to 14 days), the wound is initially irrigated and closed. The extremity is splinted with the wrist in 30 degrees of flexion and the metacarpophalangeal (MCP) joints in 50 degrees of flexion.

Special Instruments, Position, and Anesthesia

1. The patient is positioned supine on the operating table. The arm is positioned on an arm board.

2. An upper arm tourniquet is applied with cast padding.

3. The procedure may be done with general or regional anesthesia (regional anesthesia is preferred to help protect the repair while the patient awakens from anesthesia).

4. Routine small-joint orthopaedic surgical instruments are required. A Bunnell tendon retriever or #8 pediatric feeding tube may be required if the tendon has retracted proximally.

Tips and Pearls

1. The diagnosis of a flexor tendon laceration can often be made by observation. Loss of the normal cascade of the digits, with extension of the involved finger, indicates a flexor laceration. In addition, loss of the tenodesis effect or loss of passive flexion with active extension of the wrist also indicates a laceration. Finally, if the flexor tendon is intact, compression of the flexor muscles in the forearm should cause the finger to flex.

2. When testing the flexor digitorum superficialis (FDS) tendon of an involved finger, all other fingers must be in full extension. This prevents the flexor digitorum profundus (FDP) tendon from flexing the PIP joint. Remember that in some patients, the FDS of the ring and small fingers have a common muscle belly. Therefore, if the FDS of the small finger does not appear to be working, allow the ring and small fingers to flex at the same time while holding the index and middle in extension.

3. Adequate exposure is essential to achieve optimal visualization of the tendons, pulleys, and neurovascular structures.

4. If possible, repair both the FDS and FDP tendons.

5. Zone II flexor tendon repairs must be done while preserving the A2 and A4 pulleys. The most difficult repairs are those occurring at, or near, the pulleys. If possible, suture the tendon proximal to the pulley by flexing the DIP joint. If this cannot be done, the tendon is pulled distal to the pulley, the core sutures placed, and repair passed back proximally (Figs. 18–1 and 18–2).

6. The proximal end of the tendon may be hard to find when it retracts. Wrist flexion and distal massage of the flexor muscles may improve tendon visualization. In addition, one or two passes with the Bunnell tendon passer can assist in retrieving the tendon from the proximal sheath. However, repeated attempts are discouraged as they can lead to scarring in the sheath.

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