Ulnar Collateral Ligament Insertional Injuries in Pediatric Overhead Athletes: Are MRI Findings Predictive of Symptoms or Need for Surgery?

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The purpose of this study was to determine whether ulnar collateral ligament (UCL) insertion below the articular margin (so-called T sign) exists in the pediatric population and whether MRI features can be used to identify insertional UCL injuries in overhead athletes that are symptomatic or require surgery. Retrospective review of elbow MR images of patients younger than 21 years from 2011 to 2017 yielded 26 control subjects who were not overhead athletes and 97 overhead athletes. According to the clinical diagnosis, 50 of the overhead athletes had symptoms. Two radiologists evaluated the UCL for thickness, abnormal insertional signal intensity, insertion distance, and adjacent marrow or soft-tissue edema. Insertion distance was defined as the coronal length of any T sign measured from the articular margin. Mean insertion distance was greater in overhead athletes than in control subjects (1.42 vs 0.23 mm, p = 0.001) but not significantly different in athletes with symptoms compared with those without symptoms or in those who underwent operative treatment compared with those who did not. Mean UCL thickness was greater in overhead athletes than in control subjects (2.64 vs 1.74 mm, p < 0.0001), athletes with than those without symptoms (2.84 vs 2.41 mm, p = 0.005), and athletes who did versus those who did not undergo operative treatment (3.40 vs 2.73 mm, p = 0.011). Marrow (p = 0.002) and soft-tissue (p = 0.016) edema were found more frequently in athletes with symptoms. ROC analysis of UCL thickness and insertion distance as predictors of symptoms showed AUCs of 0.69 and 0.49, respectively. The T sign is likely not an anatomic variation but is a poor predictor of symptoms and need for surgery. Soft-tissue and marrow edema are more frequently seen in overhead athletes with symptomatic injuries and can aid in the diagnosis of clinically relevant injury.