Hemodynamics and metabolism in arthrosis. Studies in the rabbit knee.

Arthrosis was induced in the rabbit knee, making it unstable by ligament resection. Acidity and hypercapnia were found in the synovial fluid of the arthrotic knees, whereas oxygen partial pressure was normal. In arthrotic subchondral bone the intraosseous pressure and oxygen partial pressure were increased; intraosseous phlebography showed venous congestion. Histologic specimens showed increased subchondral bone formation, loss of cartilage and total depletion of glycosaminoglycans. The synovial membrane was hyperplastic and fibrosis was found in the underlying tissue. We suggest that changes in environmental haemodynamics and metabolism, although secondary in nature, may play an important role in the arthrotic process.