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 < .001). Sonographic joint laxity showing the ring-down artifact and concomitant tenderness with stress were significantly more frequent in the surgery group (P = .024 and P = .006, respectively). Sensitivity, specificity, and accuracy were 61.1%, 86.9%, and 75.6%, respectively, for MRI alone and 83.3%, 56.5%, and 68.2%, respectively, for the combination of MRI with joint laxity showing the ring-down artifact. For MRI in combination with joint laxity and concomitant tenderness, these values were 72.2%, 82.6%, and 78.0%, respectively.


CONCLUSIONS
The addition of stress US showing the ring-down artifact and concomitant tenderness was helpful for predicting the rehabilitation outcome of UCL injuries.
Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea.
Na Ra
NR
Kim
Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea. Electronic address: sgsgmoon@gmail.com.
Sung Gyu
SG
Moon
Department of Orthopedic Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea; Center for Shoulder, Elbow and Sports, Neon Orthopaedic Clinic, Seoul, Republic of Korea.
Jin-Young
JY
Park
Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea.
Jin Woo
JW
Choi
Department of Orthopedic Surgery, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Republic of Korea.
Kyung-Soo
KS
Oh
D000293:Adolescent; D000328:Adult; D001484:Baseball / Q000293:injuries; D000070637:Collateral Ligament, Ulnar / Q000000981:diagnostic imaging* / Q000293:injuries* / Q000601:surgery; D004551:Elbow Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D063868:Patient Outcome Assessment; D026741:Physical Therapy Modalities; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014463:Ultrasonography; D055815:Young Adult
Laxity; MRI; US; elbow; injury; ulnar collateral ligament