Pulley plasty versus resection of one slip of the flexor digitorum superficialis after repair of both flexor tendons in zone II: A biomechanical study

Background: The outcome of repair of zone-II lacerations of the flexor digitorum superficialis and flexor digitorum profundus tendons remains suboptimal. We investigated the effects of two strategies to improve postoperative gliding in a human cadaveric hand. Methods: The second, third, and fourth digits were harvested from ten fresh-frozen human cadaveric hands. Complete lacerations and repairs were made to the profundus and superficialis tendons at a location where both repair sites would pass beneath the A2 pulley with the proximal interphalangeal joint in 45° of flexion. The gliding resistance of the flexor digitorum profundus tendon was measured following pulley plasty and following excision of one slip of the flexor digitorum superficialis. The breaking strength of the remaining slip of the flexor digitorum superficialis tendon was then measured. Results: Pulley plasty and resection of one slip of the flexor digitorum superficialis tendon both significantly decreased gliding resistance compared with repair of both slips (p < 0.001). There was no difference in the mean gliding resistance between the pulley plasty and one-slip resection groups. The flexor digitorum superficialis slip was stronger after repair with a Becker suture (28.8 ± 9.0 N) than after repair with a modified Kessler (16.4 ± 4.5 N) or a zigzag suture (15.0 ± 5.7 N). Conclusion: Both pulley plasty and resection of one slip of the flexor digitorum superficialis reduce gliding resistance after tendon repair in zone II of the hand.