Value of magnetic resonance imaging in the mid-term follow-up of osteochondritis dissecans of the femoral condyle and talus.

Purpose: Definition of the prognostic value of clinical and morphological f indings in the mid-term followup of OCD of the femoral condyle and talus. D emonstration of the consolidation of OCD on MRI depending on different ther apies. Materials and Methods: 76 patients were examined before and at an av erage of 30 months after conservative or surgical therapy using T-1 and T-2 weighted SE and 3D-FISP sequences and contrast enhanced studies. Six clini cal (age, gen-der, site, duration and severity of symptoms, therapy) and si x morphological (size, signal intensity, fragmentation, contrast enhancemen t, condition of cartilage, staging) data were registered on first MRI and c orrelated with the degree of consolidation of OCD (partial and complete rem ission, no change and progression) on control MRI. Results: Patients under 17 years showed partial or complete remissions in 73%, those of 17 years or older in 33%. Conservatively treated patients had a higher remission rate (54%) than those treated with different surgical techniques (drilling 50%, refixation 43%, abrasio 38%). Small OCDs had a higher remission rate than l arge lesions (63% vs. 33%). OCDs covered with intact cartilage heated bette r than lesions with chondral defects (61% vs. 26%). Contrast enhancing frag ments had a better prognosis than non-enhancing lesions (100% vs. 40%). Con clusions: Prognosis of OCD can be better estimated when size of OCD, condit ion of cartilage and enhancement of contrast agent is graduated with MRI an d patient age is registered. The consequences for therapy planning are grea t.