Comparison of sonography and MRI in the evaluation of stability of capitellar osteochondritis dissecans

PURPOSE: To compare the diagnostic accuracies of ultrasonography (US) and magnetic resonance imaging (MRI) with intraoperative capitellar osteochondritis dissecans (COCD) fragment stability findings. METHODS: Patients whose International Cartilage Repair Society (ICRS) osteochondritis dissecans (OCD) classifications were I/II (stable) or III (unstable) were included. Patients underwent preoperative US and MRI. On US, lesions were evaluated as unstable when irregular contours of the chondral surface were observed. On MRI, lesions were evaluated as unstable when articular bone irregularity, a T2 high signal intensity interface, or a high signal intensity line through the articular cartilage was observed. Using the surgical assessment as the gold standard, accuracies of fragment stability diagnoses were calculated for US and MRI. RESULTS: Thirty‐four patients with OCD classifications of I/II (stable) or III (unstable) were included. Twenty‐four patients (stable: 12, unstable: 12) underwent preoperative US; 22 (stable: 11, unstable: 11) underwent preoperative MRI. Preoperative US and MRI stability assessments correctly matched intraoperative fragment findings in 23 of 24 patients and 16 of 22 patients, respectively. US criteria in this study achieved superior accuracy compared with MRI criteria (96% vs. 73%; P < .05). CONCLUSION: US was a useful tool for evaluating fragment instability in COCD.