Lateral Collateral Ligament Repair Restores the Initial Varus Stability of the Elbow: An In Vitro Biomechanical Study

Abstract

Lateral collateral ligament (LCL) repair of the elbow is commonly performed in the management of unstable dislocations and fracture dislocations of the elbow. The appropriateness of clinically employed techniques of LCL repair in restoring elbow kinematics and stability has not been reported. The purpose of this in vitro study was to evaluate the effectiveness of LCL transosseous sutures repair and the influence of ligament tensioning on the initial kinematics and stability of the elbow. Six cadaveric upper extremities were mounted in a motion simulator with tracking system, which enabled both passive and simulated active elbow flexion while measuring the motion of the ulna relative to the humerus. Transosseous sutures were placed in the LCL and passed through a humeral bone tunnel entering at the center of curvature of the capitellum near the lateral epicondyle with exit holes in the lateral supracondylar ridge. With the arm slightly flexed, an actuator pulled on the sutures to achieve 20, 40, and 60 N of LCL repair tension, and the sutures were then secured at that tension. Transosseous repair of the LCL restored the initial kinematics of the elbow at 20 N of tension. Greater magnitudes of initial repair tension in vitro overcorrected the varus instability causing the elbows to track in excessive valgus and internal rotation. These in vitro data suggest that LCL repair using transosseous sutures is a useful technique to restore the initial kinematics of the elbow. An LCL repair tension of 20 N or perhaps slightly less should be employed in clinical studies to confirm these laboratory observations.