Biomechanical Evaluation of the Docking Plus Ulnar Collateral Ligament Reconstruction Technique Compared With the Docking Technique

Abstract

Background:Surgical techniques for ulnar collateral ligament (UCL) reconstruction have evolved since first described by Jobe. A modified reconstruction technique has been developed, called the docking plus technique, and the authors biomechanically compared it to the commonly performed docking technique.Hypothesis:The docking plus technique for UCL reconstruction will demonstrate greater ligament stiffness than the docking technique.Study Design:Controlled laboratory study.Methods:Ten matched pairs of human cadaveric specimens (mean age ± SD, 52 ± 6 years) were loaded to failure at an elbow flexion angle of 30° at a compressive rate of 14 mm/s. The specimens underwent reconstruction with an autologous graft using the docking plus or docking technique. The reconstructed and native specimens were loaded to failure at the same parameters.Results:The most common mode of failure in the native UCL was midsubstance rupture and avulsion from the ulnar ligament insertion, while the docking plus group failed by suture rupture and the docking group by suture pullout and midsubstance rupture. The mean ± SD stiffness of the native UCL was 21.0 ± 9.0 N/mm, docking plus technique was 11.2 ± 6.6 N/mm, and docking technique was 5.3 ± 1.5 N/mm. The mean stiffness of the docking plus reconstruction was statistically greater ( P = .004) than that of the docking technique. The mean ± SD ultimate moment for the native UCL was 35.0 ± 14.0 N·m, docking plus technique was 20.6 ± 7.3 N·m, and docking technique was 8.6 ± 5.1 N·m. The moment across the elbow joint at failure of the docking plus reconstruction was statistically greater ( P = .002) than that of the docking technique.Conclusion:The docking plus technique reproduces greater ligament stiffness and demonstrates a higher failure moment immediately after reconstruction than does the docking technique.Clinical Relevance:The docking plus technique allows greater stiffness and a higher moment to failure immediately after reconstruction and describes a way to maintain constant graft tension during fixation, resulting in a biomechanically stronger UCL reconstruction.