Stress ultrasound in baseball players with ulnar collateral ligament injuries: additional value for predicting rehabilitation outcome

Background The purpose of this study was to evaluate the additional value of stress ultrasound (US) for predicting rehabilitation outcome in baseball players with ulnar collateral ligament (UCL) injury. Methods Stress US and magnetic resonance imaging (MRI) in 41 baseball players with UCL injury who received rehabilitation treatment for more than 6 weeks were retrospectively compared between the rehabilitation group (n = 23) and surgery group (n = 18). The MRI grade of UCL injury was assessed as intact continuity, low-grade partial tear, high-grade partial tear, and complete tear. To estimate sonographic joint laxity, we assessed 3 sonographic criteria as present or absent: ligamentous waviness, joint gapping, and intra-articular ring-down artifact. In addition, the presence of concomitant tenderness was checked during stress US. The diagnostic validity of MRI with and without stress US was analyzed as a predictor for the rehabilitation outcome. Results The MRI grade was higher in the surgery group than in the rehabilitation group ( P