Imaging and classification of osteochondritis dissecans of the capitellum: X-ray, magnetic resonance imaging or computed tomography?

Background: Diagnosing capitellar osteochondritis dissecans (OCD) can be difficult, causing delay in treating young athletes. The main aim of this retrospective diagnostic study was to determine which radiological technique is preferred to identify and classify elbow OCD. Methods: We identified young patients who underwent elbow arthroscopy because of symptomatic OCD. We included all patients who had pre-operative radiographs, a computed tomography (CT) scan and magnetic resonance imaging (MRI) available. We assessed whether the osteochondral lesion could be identified using the various imaging modalities. All lesions were classified according to previous classifications for X-ray, CT and MRI, respectively. These results were compared with findings at arthroscopy. Results: Twenty-five patients had pre-operative radiographs as well as CT scans and MRI. In six patients, the lesion was not visible on standard X-ray. In 20 patients, one or two loose bodies were found during surgery, consistent with an unstable lesion. Pre-operatively, this was seen on 11 X-rays, 13 MRIs and 18 CT scans. Conclusions: Capitellar OCD lesions are not always visible on standard X-rays. A CT appears to be the preferred imaging technique to confirm diagnosis of OCD. Loose bodies are often missed, especially on standard X-rays and MRIs.