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

Abstract

Techniques for ulnar collateral ligament reconstruction have evolved. Ulnar collateral ligament reconstruction with interference screw fixation restores elbow kinematics and failure strength to that of the native ligament. Controlled laboratory study. 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. 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. With this reconstruction method, failure strength was comparable with that of the native ligament and physiologic elbow kinematics were reliably restored. 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.