Biomechanical Comparison of Ulnar Collateral Ligament Reconstruction Techniques

Abstract

Background Incompetence of the ulnar collateral ligament (UCL) of the elbow is career-threatening for high-performance throwing athletes. Although multiple reconstructions have been described, a procedure that combines a larger graft with improved fixation may demonstrate more favorable loading characteristics than current techniques. Hypothesis Ulnar collateral ligament reconstructions utilizing a semitendinosus graft and interference knot fixation will be biomechanically superior to previously reported techniques. Study Design Controlled laboratory study. Methods Thirty cadaveric elbows were stripped of all medial soft tissue superficial to the UCL. The proximal humeri were mounted on a materials testing system with the elbows flexed 90°. The intact UCL was loaded to failure at 4.5 deg/s. The torsional failure moment, torsional stiffness, and mode of failure were recorded. Three groups of 10 specimens were created. Group 1 underwent reconstruction using a palmaris tendon graft secured with interference knot fixation. Group 2 reconstructions utilized a palmaris graft and the docking technique. Group 3 specimens were reconstructed using a semitendinosus graft and interference knot fixation. All specimens were loaded to failure and the same parameters recorded. Results The torsional failure moments for group 1 (13.28 Nm) and group 2 (12.81 Nm) reconstructions were significantly (P < .05) inferior to that of their respective native values (21.3 Nm and 23.5 Nm). Semitendinosus reconstructions (20.5 Nm) were not significantly different (P = .24) from their native UCLs (23.0 Nm). All reconstructions were torsionally less stiff (P < .001) than the native UCL. There were no statistically significant differences in stiffness between the groups (P = .4). Conclusion Ulnar collateral ligament reconstruction utilizing semitendinosus graft and interference knot fixation restores the torsional strength of the intact UCL. Clinical Relevance Reconstructions using semitendinosus grafts may allow for accelerated rehabilitation and earlier return to competition.