Abstract
Background and hypothesis: The original 2-strand docking technique for elbow ulnar collateral ligament reconstruction has recently been modified to use a 3-strand graft. To date, no biomechanical study has compared the 2 techniques. We hypothesized that the 3-strand docking technique would restore valgus laxity to its native state, with comparable load-to-failure characteristics to the 2-strand docking technique. Materials and methods: Sixteen fresh cadaveric elbows were matched to the corresponding contralateral side from the same individual to create 8 matched pairs and were then randomized to undergo ulnar collateral ligament reconstruction using either the 2- or 3-strand technique. Valgus laxity and rotation measurements were quantified using a MicroScribe 3DLX digitizer at various flexion angles for the native state, transected state, and 1 of the 2 tested reconstructed ligaments. Each reconstruction was then tested to failure. Results: Valgus laxity for the intact state at elbow flexion angles of 30° 60° 90° and 120° was 7° ± 2° 7° ± 2° 6° ± 1° and 5° ± 2° respectively. These values were similar to those of both reconstruction techniques. On load-to-failure testing, there was no significant difference in any parameter recorded. Yield torques for the 3- and 2-strand reconstructions were 13.4 ± 4.80 N/m and 11.8 ± 4.76 N/m, respectively (P =.486). The ultimate torques were 15.7 ± 6.10 N/m and 14.4 ± 5.58 N/m for the 3- and 2-strand techniques, respectively (P =.582). Conclusion: The 3-strand docking technique was able to restore valgus laxity to the native state, with similar load-to-failure characteristics to the 2-strand docking technique. © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees