Biomechanical evaluation of a new ulnar collateral ligament reconstruction technique with interference screw fixation

Abstract

Background: Techniques for ulnar collateral ligament reconstruction have evolved.

Hypothesis: Ulnar collateral ligament reconstruction with interference screw fixation restores elbow kinematics and failure strength to that of the native ligament.

Study design: Controlled laboratory study.

Methods: Of 10 matched pairs of cadaveric elbows, one underwent kinematic testing under conditions of an intact, released, and reconstructed ligament. Single 5-mm diameter bone tunnels were created at the isometric anatomic insertion sites on the medial epicondyle and sublime tubercle. Graft fixation was achieved with 5 x 15 mm soft tissue interference screws. The reconstructed and contralateral intact elbows were then tested to failure.

Results: Average stiffness for intact elbows (42.81 +/- 11.6 N/mm) was significantly greater than for reconstructed elbows (20.28 +/- 12.5 N/mm). Ultimate moment for intact elbows (34.0 +/- 6.9 N.m) was not significantly different from reconstructed elbows (30.6 +/- 19.2 N.m). Release of the ulnar collateral ligament caused a significant increase in valgus instability. Reconstruction restored valgus stability to near that of the intact elbow.

Conclusions: With this reconstruction method, failure strength was comparable with that of the native ligament and physiologic elbow kinematics were reliably restored.

Clinical relevance: This technique returns elbow kinematics to near normal, with less soft tissue dissection and risk of ulnar nerve injury and ease of graft insertion, tensioning, and fixation.