Evaluation of an interference screw for tendon reattachment to small bones.

Objectives: To compare the strength of interference screw fixation of the tendon to suture button fixation and staple fixation methods. Design: Biomechanical study. Methods: The femurs and flexor digitorum tendon of twelve rabbits were used. The tendon was attached to the medial condyle of the femur using one of the following three surgical procedures: (a) interference screw fixation: tendon-junction screw was used as an interference screw, (b) Suture button fixation: the tendon was inserted through a hole and attached with a button on the opposite side, and (c) staple fixation: the tendon was attached using two staples. Strengths of the attached tendons were then measured using a universal testing machine. Results: The Ultimate failure load of interference screw fixation was 62.8 +/- 9.0 N. whereas that of suture button fixation was 13.9 +/- 3.8 N and staple fixation was 23.9 +/- 2.6 N. Conclusion: Interference screw fixation provides significant initial fixation strength (p < 0.05).