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.