Comparison of postoperative early active mobilization and immobilization in vivo utilising a four-strand flexor tendon repair

We evaluated a technique of four-strand double-modified locking Kessler flexor tendon repair in healing tendons. Seventy-two canine flexor digitorum profundus tendons in Zone 2 were repaired and evaluated following either active mobilization or immobilization at 0, 7, 14, 28 and 42 days after surgery. Fifty-six tendons were examined for gap and ultimate strength using a tensile testing machine and 16 were evaluated with standard hematoxylin and eosin, and Masson's trichrome staining. All tendons healed without rupture or gap formation of more than 1 mm, thus demonstrating that this repair technique has enough tensile strength to withstand early active mobilization. The gap and ultimate strength of actively mobilized tendons did not decrease significantly during the first 7 days, and were significantly greater than those of immobilized tendons throughout the 42-day study period. Actively mobilized tendons heated without the extrinsic adhesions and large tendon calluses that were found in immobilized tendons.