Biomechanical Evaluation of 4-Strand Flexor Tendon Repair Techniques, Including a Combined Kessler–Tsuge Approach

PurposeTo test the ultimate tensile strength and stiffness of 3 flexor tendon repair techniques using looped suture material.MethodsSeventeen fresh porcine flexor tendons were randomized to a single-throw, 4-strand Kessler technique with a looped structure, a double-throw, 4-strand Tsuge technique with 2 looped structures, or a single-throw, 4-strand Kessler–Tsuge technique with a looped structure. Thirty additional fresh porcine flexor tendons were randomized to the same techniques but with a running epitendinous repair. We measured ultimate tensile strength to failure and stiffness and recorded the cause of failure.ResultsThe Tsuge technique had the highest mean ultimate tensile strength at 75 N (SD, 14 N) versus 63 N (SD, 13 N) for the Kessler–Tsuge method and 46 N (SD, 11 N) for the Kessler technique. Differences between the Tsuge and Kessler–Tsuge, the Kessler–Tsuge and Kessler, and the Tsuge and Kessler techniques were significant. Mean suture stiffness was 6.8 N/mm for the Tsuge technique, 5.7 N/mm for the Kessler–Tsuge technique, and 4.6 N/mm for the Kessler technique. The difference between the Tsuge and Kessler techniques was significant. Analyzing the tests with or without an epitendinous suture separately did not affect the significance of the differences.ConclusionsThe modified double-throw, 4-strand Tsuge was the strongest suture technique in this study. It may be a clinically acceptable, albeit slightly weaker alternative to the more complicated Tsuge method.Clinical relevanceA combined Kessler–Tsuge approach might be an option for flexor tendon repair.