Peritendinous healing after early movement of repaired flexor tendon: anatomical study

In 64 chickens the deep flexor tendon of the third toe was divided and resutured, preserving the sheath and flexor sublimis tendon. The leg was placed in a cast for 35 days postoperatively; in some birds minimal flexion of the toes was induced by electrical stimulation of the deep flexor muscle in the last 17 days of cast immobilization. At day 35 the cast was removed, and the return of flexion carried out in the third toe was measured up to day 60. Assessment of the tendon repair site was at 18, 35, and 60 days. Restored peritendinous connections in specific areas were similar to those in controls. Early movement resulted in fewer adhesions, a significantly higher incidence of free intertendinous spaces (standard error of difference = 6.3, difference = 14.5%), and significant lengthening of bridges between the flexor profundus and phalanx (p = 0.01). The effect of early movement gradually decreased from the dorsal to the ventral structures.