Professional Pitchers Display Differences in UCL Morphology and Elbow Gapping During Moving Valgus Stress Testing After UCL Reconstruction.

Background: Ulnar collateral ligament (UCL) reconstruction (UCLR) of the elbow has received much attention given the rise in incidence among baseball pitchers. Stress ultrasonography has been demonstrated to be a critical evaluation tool of the UCL. No study has dynamically evaluated the ability of UCLR to restore normal kinematics.
Purpose/hypothesis: The purpose of this study was to compare ulnohumeral gapping during a moving valgus stress test as well as UCL thickness between professional pitchers with and without UCLR. We hypothesized that the ulnohumeral joint will display greater gapping and the UCL graft will be thicker in pitchers after UCLR compared with uninjured pitchers.
Study Design: Cross-sectional study; Level of evidence, 3.
Methods: Ultrasonography was used to measure the medial ulnohumeral joint distance and the UCL thickness of 70 asymptomatic professional baseball pitchers; 6 of the participants had a history of UCLR. Images were captured of the dominant (D) and nondominant (ND) elbows at the maximal cocking position under 2 loaded conditions within the moving valgus stress test arc: (1) gravity stress and (2) 2.5 kg (5.5 lb) of valgus force using a dynamometer. Intra- and interrater reliability of the measurements was established with intraclass correlation coefficients (ICCs). Separate mixed-model analyses of variance (D side × UCL) were used to compare the D and ND elbow variables between pitchers with and without a history of UCLR.
Results: All measurements displayed good reliability according to ICCs. Pitchers with a history of UCLR demonstrated less gapping (5.6 ± 2.9 vs 4.2 ± 1.2 mm; P = .002) and greater UCL graft thickness (0.17 ± 0.07 vs 0.11 ± 0.08 mm; P = .03) compared with the native ligament in pitchers without prior UCL injury.
Conclusion: Our data demonstrated that the UCLR results in a thicker, stiffer construct with less medial elbow gapping than the anatomical UCL. Using ultrasound to evaluate the UCL was a reliable, efficient, and clinically feasible method to assess UCL thickness and joint gapping in players with a history of UCLR. Future studies may consider this approach to evaluate surgical techniques and graft types for UCLR.
Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: M.J.K. has received educational support from Arthrex and Peerless Surgical, consulting fees from Arthrex, speaking fees from Arthrex, and hospitality payments from Exactech. C.A.T. has received research support from Arthrex and Neurotech-Kneehab, consulting fees from Breg, speaking fees from Arthrex, and stock/stock options in Players Health and Trex. D.J.G. has received educational support from Arthrex and hospitality payments from Encore Medical, Mid-Atlantic Surgical, Smith & Nephew, and Stryker. M.L.S. has received educational support from Arthrex. D.J.W. has received research support from Zimmer Biomet; educational support from Peerless Surgical; consulting fees from Arthrex, Ceterix, and Zimmer Biomet; and speaking fees from Arthrex. R.J.H. has received grant support from Encore Medical, educational support from Arthrex, consulting fees from Arthrex and Pacira Pharmaceuticals, speaking fees from Arthrex, and royalties from Encore Medical. T.J.N. has received educational support from Gemini Mountain and consulting fees from Stryker. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
(© The Author(s) 2021.)