A retrospective evaluation of magnetic resonance imaging effectiveness on capitellar osteochondritis dissecans among overhead athletes.

BACKGROUND

Magnetic resonance imaging (MRI) has been widely used to characterize osteochondritis dissecans (OCD) lesions. However, the usefulness of MRI for predicting fragment stability in OCD of the humeral capitellum (capitellar OCD) remains unclear.

HYPOTHESIS

Preoperative MRI cannot accurately diagnose fragment instability of capitellar OCD in overhead athletes.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 1.

METHODS

Twenty-seven male overhead athletes who had undergone surgery for capitellar OCD were included in the study. A single senior musculoskeletal radiologist blindly reviewed preoperative MRI of these OCD lesions. The radiologist reported the presence or absence of each of the 4 MRI signs indicating fragment instability as described by De Smet et al. The lesions were also classified according to the MRI staging system of Dipaola et al for characterizing the lesions. Intraoperative assessment of fragment stability was used as the gold standard. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined for fragment instability as assessed by MRI.

RESULTS

According to the MRI criteria by De Smet et al and the Dipaola et al staging system, 21 (78%) and 20 (74%) lesions were defined as unstable, respectively. The obtained results yielded a sensitivity of 89% and a specificity of 44% for diagnosing fragment instability using the De Smet et al MRI criteria and a sensitivity of 83% and a specificity of 44% using the Dipaola et al MRI staging system. The PPV and NPV for fragment instability were 76% and 67% using the De Smet et al criteria and 75% and 57% according to the Dipaola et al staging system, respectively. The overall correlation rate of Dipaola et al MRI and intraoperative stages was 41%.

CONCLUSION

Preoperative MRI cannot precisely diagnose fragment instability of capitellar OCD that requires operative treatments in overhead athletes. Especially, MRI indicating stable lesions is considered not to be useful in predicting intraoperative instability of capitellar OCD in this study population.