Osteochondritis dissecans (OCD) is a localised disorder of subchondral bone and the overlying articular cartilage. The most commonly used classification systems involve arthroscopy and MRI.
To investigate the correlation between arthroscopic and MR findings in patients with OCD of the talus.
16 ankles in 14 patients with radiographically proven OCD were reviewed. Nine were male and five female. Mean age was 35yrs (range 18–64yrs). The lesions were staged independently using the Guhl
Arthroscopically there were eight stable and eight unstable lesions. Of the eight stable lesions, MRI staged five as stable and three as unstable. Of the eight unstable lesions, MRI staged six as unstable and two as stable. This gives a sensitivity of diagnosing unstable lesions as 0.75, with a specificity of 0.63.
This small study demonstrates that MR scans may have some limitations in classifying OCD lesions of the talus. Possible explanations are discussed. We propose that MRI findings, of OCD of the talus, should not be taken in isolation, but correlated with the patients symptoms and signs to avoid unnecessary arthroscopy.
