Comparison of loop-tendon versus end-weave methods for tendon transfer or grafting in rabbits

The loop-tendon method for the stabilization of tendon transfers or grafts has been demonstrated previously to have greater initial tensile strength than that of the end-weave method. To our knowledge, a comparison of the mechanical strengths of these methods over the early postoperative period has not been made. The purpose of this study was to compare the mechanical strengths of loop-tendon and end-weave methods of repair during the early postoperative period in rabbit hind limb tendons.

In bilateral hind limbs of 30 New Zealand white rabbits of an average weight of 3.5 kg, a distally cut gastrocnemius Achilles' tendon and a proximally cut flexor digitorum superficialis tendon were connected to each other by using the loop-tendon method with 5 stitches in one limb and a 1-pass end-weave method in the contralateral limb. Postoperatively, all rabbits were immobilized by a short-leg cylinder cast. Six rabbits were killed at each of the following time points: immediately after surgery (baseline) and at 1, 2, 3, and 4 weeks postoperatively. Repaired tendons were harvested and were loaded to failure in a tensile load-testing machine to record the ultimate strength and to calculate the absorbed energy.

Ultimate tensile loads were significantly higher in the loop-tendon method group than in the end-weave group from baseline to 3 weeks postoperatively, but there was no difference at 4 weeks postoperatively. During the postoperative period, the ultimate tensile load and absorbed energy decreased over the first 2 weeks postoperatively and then increased to reach baseline strengths at 3 weeks postoperatively in both groups.

The loop-tendon method provided greater strength than that of the end-weave method during the early postoperative period in rabbit tendons. The loop-tendon method may provide greater surgical repair strength during the early postoperative rehabilitation period than the end-weave method.