A2 pulley incision or one slip of the superficialis improves flexor tendon repairs

Outcomes of flexor tendon repairs in the area covered by major pulleys are often unpredictable. We performed an in vivo study to investigate biomechanical effects of pulley incision, Kapandji pulley plasty, excision of one slip of the flexor digitorum superficialis, or closure of the incised pulley on function of the profundus tendons. Both long toes (104 total) of 52 leghorn chickens were divided into four experimental groups and one control group. The pulley and flexor digitorum superficialis tendon were subjected to the above-mentioned treatments in four groups, with 22 toes per group, after tendon transection in the A2 pulley area. Eight weeks after surgery, incision of the pulley improved excursion of the flexor digitorum profundus tendon and decreased the work of digital flexion over pulley closure. Resection of the one slip of the flexor digitorum superficialis tendon had results similar to pulley incision. Kapandji pulley plasty did not increase tendon excursion and decrease the work compared with a simpler pulley incision. Adhesions were more severe with pulley plasty or closure than with pulley incision. In this avian model, incision of the pulley or partial flexor digitorum superficialis resection improved outcomes of tendon repairs compared with pulley closure. Kapandji pulley plasty did not improve the outcomes over a simple pulley incision.