Traumatic hemarthrosis in stable knees.

A thorough arthroscopic examination was performed in 90 consecutive patients with sprained knee injuries with hemarthrosis, but without signs of instability or fracture. The source of bleeding was found in all but five joints. Thirty-nine injuries were tears of the cruciate ligament, only three of which were complete tears. Fourteen injuries were (osteo)chondral fractures and six were meniscal lesions. The remainder bled from the synovium or meniscal attachments. The arthroscopic examination resulted in an altered course of treatment in few, if any, of these patients.