Prevalence of Capitellar Osteochondritis Dissecans in Children With Chronic Radial Head Subluxation and Dislocation.

OBJECTIVE: An abnormal radiocapitellar articulation may play a role in the development of capitellar osteochondritis dissecans (OCD). The objective of this study is to determine the prevalence of capitellar OCD in pediatric patients with chronic radial head subluxation (RHS) or radial head dislocation (RHD).

MATERIALS AND METHODS: We searched the radiology reports generated at a large pediatric hospital between 2004 and 2012, to identify patients 8-18 years old with chronic RHS or RHD. Patients with underlying bony abnormalities that could obscure, be confused with, or increase the risk of OCD of the elbow were excluded. Two pediatric radiologists assessed images of the elbow, grading radiocapitellar alignment as follows: normal, subluxed, dislocated, or intermittently subluxed and dislocated. Readers also reviewed images to detect capitellar OCD. The differences in the prevalence of OCD noted in elbows in each category of radiocapitellar alignment were assessed.

RESULTS: A total of 118 cases of chronic RHS, RHD, or both were detected in 100 patients. The radiocapitellar alignment of these cases was defined as follows: 53-58% were dislocated, 26-31% were subluxed, 14-15% were intermittently subluxed and dislocated, and less than 1% had normal alignment. There were 14 cases of capitellar OCD (11.9%). One elbow with OCD was categorized by both readers as dislocated, with the remaining 13 elbows (93%) deemed by the two readers to be either subluxed or intermittently subluxed and dislocated. The percentage of elbows with RHS that were found to have capitellar OCD was 32.3-33.3%, compared with 1.4-1.6% of elbows with RHD.

CONCLUSION: The prevalence of capitellar OCD is greater in elbows with RHS than in those with RHD. This finding suggests that abnormal radiocapitellar mechanics are a factor in the development of OCD. In children with RHS and new or worsening pain, capitellar OCD should be considered, and imaging strategies should be directed toward early identification of this important and treatable condition.