Osteochondritis Dissecans of the Elbow in Children: MRI Findings of Instability.

OBJECTIVE. The purpose of this study was to investigate the performance of MRI criteria for predicting instability of osteochondritis dissecans (OCD) lesions of the elbow in children. MATERIALS AND METHODS. This retrospective study included 41 children with 43 OCD lesions of the elbow who underwent an MRI examination between April 1, 2010, and May 31, 2018. Two radiologists blinded to clinical outcomes reviewed MRI studies to determine the presence or absence of joint effusion, osteochondral defect, intraarticular body, overlying cartilage changes, subchondral bone disruption, rim of high signal intensity on T2-weighted images, cysts, marginal sclerosis, and perilesional bone marrow edema. The stability of OCD lesions was determined with clinical follow-up and surgical findings as reference standards. Mann-Whitney U, chi-square, Fisher exact, and Cochran-Armitage tests were used to compare MRI findings between stable and unstable OCD lesions. RESULTS. There were 20 stable and 23 unstable OCD lesions. An osteochondral defect (p = 0.01), intraarticular body (p < 0.001), overlying cartilage changes (p = 0.001), subchondral bone plate disruption (p = 0.02), and hyperintense rim (p = 0.01) were significantly more common in unstable than stable OCD lesions. However, only osteochondral defect and intraarticular body were 100% specific for OCD instability. There was no significant difference between stable and unstable OCD lesions in the presence of joint effusion (p = 0.10), cysts (p = 0.45), marginal sclerosis (p = 0.70), or perilesional bone marrow edema (p = 1.00). CONCLUSION. MRI findings of OCD instability of the elbow include an osteochondral defect, intraarticular body, overlying cartilage changes, subchondral bone disruption, and rim of high signal intensity on T2-weighted MR images.