Biomechanical Evaluation of Ulnar Collateral Ligament Reconstruction of the Elbow Using the Docking Technique

INTRODUCTION In the functional range of elbow flexion (approximately 20 to 120) the anterior bundle of the Ulnar Collateral Ligament (UCL) has been shown to function as the primary stabilizer against valgus stresses [1,2]. Injuries to this ligament are common among throwing athletes. Surgical reconstruction of the UCL is frequently performed using the Docking technique [3] and has achieved successful results. Biomechanical studies have been conducted in the past to evaluate the effect of this and other types of reconstruction surgeries on elbow mechanics [4]. Reconstruction has been suggested at 30 degrees of elbow flexion as well as at greater degrees of elbow flexion (90 degrees) approximating the elbow flexion position during throwing. No quantitative biomechanical data exists to provide guidelines for the appropriate elbow flexion angle at which surgical reconstruction should be performed. This study is based on the hypothesis that the Biomechanical characteristics of the reconstructed elbow, including valgus laxity, load to failure in valgus and kinematic coupling between ulnar deviation and valgus rotation are significantly affected by the flexion angle at which the surgical reconstruction was performed. The goal of this study is to evaluate the validity of this hypothesis and identify a biomechanically optimal flexion angle at which surgery should be performed.