Biomechanical Comparison of Stability and Strength After Ulnar Collateral Ligament Reconstruction With Suture Anchor Fixation Versus Bone Tunnels

Abstract

Background: Ulnar collateral ligament (UCL) injuries occur frequently in baseball players, and UCL reconstruction is performed when nonoperative treatment fails. Purpose: To compare a novel all-suture anchor method of UCL reconstruction with a method using bone tunnels (Ito method) by investigating the displacement against valgus torque and the failure strength. Study Design: Controlled laboratory study. Methods: Eight fresh-frozen cadaveric upper extremities (mean age, 82.0 years) were utilized in this study. To evaluate the displacement against valgus torque, the valgus stability test was performed for 4 anterior oblique ligament (AOL) conditions: intact AOL, resected AOL, reconstructed using the anchor method, and reconstructed using the Ito method. The load-to-failure test was performed to evaluate the failure strength of the anchor and Ito methods. Displacement against valgus load was compared between conditions using the repeated-measures 2-way analysis of variance with Bonferroni post hoc test, and failure strength between the anchor and Ito methods was compared using the unpaired t test. Results: Displacements of the intact AOL and anchor method were significantly greater than those of the resected AOL at both 60° and 90° of flexion (intact AOL: P = .005 and P < .001, respectively; and anchor method: P = .024 and P < .001, respectively). The displacement of the Ito method at 90° of flexion was significantly greater than that of the resected AOL ( P = .003), but no significant difference was observed at 60° of flexion ( P = .109). There were no significant differences in displacement between the anchor and Ito methods at any flexion angle, nor was there a significant difference in failure torque between the anchor and Ito methods (16.3 ± 3.1 vs 17.6 ± 2.3 N·m, respectively; P = .537). Conclusion: The displacement and failure strength against a valgus load after UCL reconstruction using a suture anchor on the ulnar side were equal to those using bone tunnels. Clinical Relevance: UCL reconstruction using a suture anchor on the ulnar side is simpler and less invasive than using bone tunnels, with similar outcomes.