Elbow Ulnar Collateral Ligament Reconstruction and Repair: A Systematic Review and Meta-analysis of Biomechanical Studies.

Background: Technical variations in elbow ulnar collateral ligament reconstruction (UCLR) include graft source, graft/tunnel configuration, and humeral and ulnar fixation. While the biomechanical performance of various constructs has been reported, these studies have small sample sizes and compare at most a few technical variations. Purpose: To quantitatively synthesize the results of biomechanical investigations of UCLR and repair. Study Design: Systematic review. Methods: A systematic review and meta-analysis was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses); included articles were published between 1998 and 2020. Biomechanical metrics were utilized to compute effect sizes (standardized mean difference [SMD]) for quantitative analysis when 2 studies reported the same metric for the same comparison. After our initial search, 1293 studies were identified. Summary effects were estimated in random-effects models, and mixed-effects models were constructed to evaluate the fixed effects of technical variations through meta-regression. Results: A total of 24 eligible studies were included, of which 19 were included in the quantitative analysis. Compared with the intact ligament, UCLR had significantly lower ultimate strength (SMD, -1.411; Conclusion: Our study demonstrates that, at time zero, UCLR has inferior biomechanical properties compared with the native intact ligament. Biomechanical performance of UCLR was either inferior to the intact UCL (ultimate strength, stiffness [N/mm], and valgus opening at 70° flexion) or not significantly different from it (stiffness [N⋅m/deg], valgus opening at 30° and 90° of flexion, and gapping at failure). There is no difference in biomechanical outcome measurements between docking and Jobe reconstructions, or between UCL repair and reconstruction.