Intersurgeon Consistency of Ulnar Collateral Ligament Repair With Internal Brace: A Biomechanical Analysis

Abstract

Background:

Injury to the ulnar collateral ligament (UCL) of the medial elbow has been treated successfully with ligament repair augmented with internal brace. Previous work has shown that this procedure does not overconstrain the ulnohumeral joint; however, the procedures were conducted by a single surgeon, which controlled for anchor placement and graft tensioning.

Purpose/Hypothesis:

Our purpose was to evaluate the reproducibility of contact mechanics and joint torque after UCL repair with internal brace as performed by different surgeons compared with repair by a single surgeon. It was hypothesized that there would be no significant difference in elbow contact mechanics, valgus torque, or torsional stiffness between the 2 groups.

Study Design:

Controlled laboratory study.

Methods:

Nine pairs of fresh-frozen cadaveric elbows were tested biomechanically under 3 conditions: UCL-intact (UCL-I), UCL-deficient (UCL-D), and UCL-repaired with internal brace augmentation (UCLR-IB). For each pair, 1 elbow was repaired by a single surgeon, and the contralateral elbow was repaired by 1 of 9 other surgeons. Testing consisted of valgus torsion between 0° and 5° with the elbow positioned at 90° of flexion. Ulnohumeral contact mechanics and overall joint torque and stiffness were measured and compared between surgeon groups.

Results:

There were no statistically significant differences between the single-surgeon and multiple-surgeon groups regarding contact area ( P = .83), contact force ( P = .27), peak pressure ( P = .26), or peak force ( P = .30); however, contact pressure was significantly affected ( P = .02) by surgeon group. Compared with UCL-I, both UCL-D and UCLR-IB conditions had a significant overall effect on contact area ( P = .004) and contact force ( P = .05); however, contact pressure ( P = .56), peak pressure ( P = .27), and peak force ( P = .24) were not affected by injury condition. Measurements of elbow torque ( P = .28) and stiffness ( P = .98) were not significantly different between surgeon groups.

Conclusion:

UCL repair with internal brace provided consistent results among several surgeons when compared with a single surgeon. The procedure did not lead to joint overconstraint while also returning the ligament to near-intact levels of resisting valgus stress.

Clinical Relevance:

UCL repair with internal brace augmentation is a reproducible surgical technique that has good clinical outcomes in the literature.