[Osteochondritis dissecans of the knee joint].

Osteochondritis dissecans is a disorder with a prevalence of 0.01 to 0.06 %. Men between 16 and 36 years of age are most commonly affected by it. In the western hemisphere, the knee is affected by this progressive disorder in 75 % of the cases, specifically the medial femoral condyle (70 - 80 %). The etiology is uncertain, although genetic defects, micro-trauma, ossification disorders and ischemia have been implicated. Pathogenetically, Osteochondritis dissecans is classified in four stages, whereas in stage one, there is merely a subchondrial edema. Without therapy this could lead to stage 4, with a free osteochondral joint fragment. Treatment is analogous with the stage of the disorder. Whereas conservative treatment may yield full recovery during stage 1, starting in stage 2, invasive treatment should be considered. When the cartilage surface remains intact retrograde procedures are indicated. If the cartilage is injured anterograde therapies, like the chondral or osteochondral transplantation, should be used.