Review Question - QID 219918

This patient has a grade IV traumatic pulley injury to the middle finger. Without surgical reconstruction of his pulley system, he is likely to develop bowstringing of his flexor tendons which will result in a painful flexion contracture (Answer 4).

Pulley injuries are relatively rare injuries that occur mainly in avid rock climbers. However, they are encountered in traumatic lacerations of the hand, as well as in baseball players and patients who pick up heavy objects with their fingers in the crimped position. Grade I injuries involve a strain of the affected pulley, while Grade II and III injuries involve complete ruptures of A4, and A2/A3 respectively. Grade IV injuries involve multiple pulley ruptures or combined lumbrical and collateral ligament injuries. The majority of pulley injuries can be treated nonoperatively, but severe injuries (Grade IV), require surgical reconstruction to prevent clinically significant bowstringing. Bowstringing leads to progressive pain and flexion contractures to the affected digit due to the loss of mechanical advantage of the digit extensor mechanism.

Zafonte et al. perform a narrative review of the flexor pulley system, describing the anatomy, injury, and surgical and nonoperative management. For closed injuries, they recommend MRI or ultrasound imaging to diagnose a flexor tendon pulley injury. They suggest nonoperative management for most injuries, but for severe injuries recommend a reconstructive procedure, not repair.

Clark et al. review the surgical anatomy and technique for flexor pulley reconstruction. They describe two main techniques - nonencircling weave techniques and loop reconstruction. They review the technique of loop reconstruction, which is biomechanically superior. They emphasize the importance of hemostasis to prevent postoperative adhesions and careful assessment of flexor tendon excursion after reconstruction.

Schoffl et al. present a case series of 604 rock climbers with overuse upper extremity injuries. They identified 122 patients with pulley injuries and proposed the most commonly used classification to date. In the majority of patients treated nonoperatively 92% returned to climbing activity at their previous level. 7 patients with grade IV injuries treated with reconstruction had good results, with 1 patient able to climb at a very high difficulty level, and most of the rest still able to climb.

Figure A is a clinical photo of a patient with a severe laceration to the middle finger, with transection of the A2, A3, and A4 pulley.

Illustration 1 is a table representing the Schoffl classification of pulley injuries. Illustration 2 is a clinical photo of a pulvertaft non-encircling weave technique for A2 pulley reconstruction utilizing palmaris longus autograft.

Incorrect answers:
Answer 1: The patient does not have a flexor tendon injury, and neglecting to repair the pulleys does not increase the risk of flexor tendon rupture.
Answer 2: Quadriga effect occurs when a patient sustains a flexor digitorum profundus (FDP) tendon injury which is repaired short, leading to poor common muscle belly excursion and a flexor lag in the surrounding digits.
Answer 3: The lumbrical plus effect occurs when one digit sustains a FDP injury distal to the lumbrical insertion, resulting in paradoxical interphalangeal extension with metacarpophalangeal joint flexion due to the pull of the intact lumbricals.
Answer 5: With a neglected grade IV pulley injury with complete transection of A2, A3, and A4 pulleys, the patient is likely to have clinically significant bowstringing and subsequently develop a flexion contracture.