D140. Biomechanical Comparison of the Double Opposing Locking Loop (DOLL), Lim/Tsai and Modified Kessler Flexor Tendon Repair Techniques

PURPOSE: We performed a biomechanical comparison of the double opposing locking loop (DOLL) 4-strand flexor tendon repair technique with the Lim/Tsai 6-strand and modified Kessler 4-strand repairs. METHODS: 30 FPL, FDP, and FDS cadaveric flexor tendons were harvested and transverse zone 3 lacerations were created. Tendons were repaired using one of 3 techniques: DOLL, Lim/Tsai, and modified Kessler. Repair strength was tested using an Instron materials testing machine. Maximum load, load at 2 mm, repair stiffness, and mechanism of failure were recorded. RESULTS: The Lim/Tsai and DOLL repairs had significantly greater maximum load than the modified Kessler repair, with Lim/Tsai showing the greatest average maximum load. The DOLL repair had significantly greater 2 mm gap force and stiffness than both the Lim/Tsai and Kessler repairs. There was no significant difference in 2 mm gap force between Lim/Tsai and Kessler repairs. Failure mode of the DOLL and Lim/Tsai was most often suture breaking, while tendon tear-through was most common with the modified Kessler. High degree of gapping in the Lim/Tsai suggests some tendon tear-through before the eventual failure of the suture. CONCLUSION: Although the biomechanical strength of the Lim/Tsai 6-strand repair was greatest, it is less stiff and less resistant to gap formation than the DOLL 4-strand repair. Balancing strength and gaping data, we believe the DOLL repair to be the strongest in our study.