Evaluation of Differences in Imaging Findings on Stress-MRI in Throwing Athletes With and Without a History of Ulnar Collateral Ligament Reconstruction

Background: Ulnar collateral ligament (UCL) reconstruction (UCLR) of the elbow is common in throwing athletes and reliably allows return to play. The literature supports stress imaging of the elbow to evaluate the integrity of the UCL. The FEVER view (flexion, external rotation, and valgus stress) was developed to improve the diagnostic accuracy of UCL pathology in throwing athletes with stress magnetic resonance imaging (MRI). Hypothesis/Purpose: The present study sought to evaluate FEVER MRI imaging findings, primarily ulnohumeral joint space widening, in patients with and without a history of UCLR. The authors hypothesize that on the FEVER view there would be no difference in joint space widening between pitchers with a history of UCLR and those without. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Pitchers in 2 Major League Baseball franchises who underwent preseason screening MRIs with standard and FEVER views were included. All images were read by 2 fellowship-trained musculoskeletal radiologists. Findings included gross UCL appearance, UCL edema, location of edema, type of signal, grade of injury, ligament retraction, and amount of ulnar-sided joint space opening (absolute opening, the joint space widening in the FEVER stress view; relative opening, the difference between joint space widening in the FEVER view and standard view joint space widening). Time from surgery was evaluated for impact on imaging findings. Results: There was a statistically significant increase in absolute medial-sided joint space opening in players with a history of UCLR (n = 18; mean, 4.5 ± 3.4 years between UCLR and MRI) versus no UCLR (n = 76) (4.3 vs 3.8 mm; P = .04) and increased grade of UCL signal ( P = .034) in patients with a history of UCLR. There was no difference in the other imaging parameters, including relative joint space opening (2.2 vs 1.9 mm; P = 0.11). Time from surgery was not associated with any outcome variables. Conclusion: Valgus stress MRI (the FEVER view) showed a slight, but significant increase in absolute joint space opening after UCLR and an increased grade of intrasubstance UCL signal. However, there was no difference in relative joint space opening, and the clinical significance of these findings is unclear and warrants further study.