[Clinical value of conventional radiology and MRI in assessing osteochondrosis dissecans stability]

A prospective study was performed on 72 patients with osteochondritis dissecans (OD) of the knee and ankle to compare plane radiography, MRI and arthroscopy before therapeutic procedures. Special interest was placed on the assessment of fragment stability with radiological methods for staging related therapy. OD was localized in 46 cases on the femoral condyle and in 26 cases on the talus. Radiological methods were performed simultaneously and shortly before definite arthroscopical therapy. Using conventional radiography, OD of the condyles was staged according to the classification of Rodegerdts and Gleissner and OD of the talus suggested by Berndt and Harty. MRI staging was performed by morphology of the interface of the OD. Arthroscopical staging based on the classification of Guhl. There was an excellent correlation between the stages in MRI and arthroscopy, showing correct prediction of stable and unstable fragments in 92%. In contrast, fragment stability could not be efficiently assessed by conventional radiology because fragments could be stably fixed in cases of bony separation. MRI is indicated before performance of staging-related therapy of OD to select patients with stable fragments for conservative therapy and those with unstable OD for surgical therapy.