Biomechanical Comparison of Ulnar Collateral Ligament Reconstruction with and without Internal Bracing

Abstract

Objectives:A common concern associated with elbow ulnar collateral ligament (UCL) reconstruction surgery is the amount of time required for recovery and rehabilitation. For example, the average time to return to competition is around 15-18 months for major league baseball pitchers. The Internal Brace (Arthrex Inc.) has shown to provide additional soft tissue stability across other joints in the body. By providing an additional checkrein to the UCL reconstruction while the graft is healing, it may be possible to expedite the rehabilitation process in throwing athletes, providing a quicker return to sport.Purpose:To compare elbow valgus stability and load to failure between UCL reconstructions with and without suture augmentation.Methods:24 fresh-frozen cadaveric elbows were dissected to expose the UCL. Medial elbow stability was tested with the UCL intact, deficient, and reconstructed utilizing the 3-ply docking technique either with or without suture augmentation. A 3 N·m valgus torque was applied to the elbow and valgus rotation of the ulna was recorded via motion tracking cameras as the elbow was cycled through a full range of motion. After kinematic testing, specimens were loaded to failure at 70 degrees of elbow flexion.Results:UCL-deficient elbows demonstrated significantly greater valgus rotation compared to intact and internally-braced reconstructed elbows at every angle of flexion tested and at 50-120o flexion when compared to un-braced UCL reconstructed elbows, p<0.05. There were no significant differences at any angle of flexion between intact and UCL reconstructed elbows both with and without an internal brace at any flexion angle tested. Braced reconstructions had consistently greater valgus stability at every angle tested compared to unbraced reconstructions, but this was not significant, Figure 1B. When loaded to failure un-braced reconstructed elbows failed at a significantly lower torque value compared to UCL reconstructions with a brace, p<0.01, Figure 1A.Conclusions:UCL reconstruction with internal bracing does not over constrain the elbow throughout all flexion angles when compared to the 3-ply docking technique while providing greater biomechanical stiffness. Internal bracing may provide the additional stability necessary to accelerate rehabilitation following ulnar collateral ligament reconstruction.