Oxygen consumption, diffusing capacity and blood flow of the synovial membrane in osteoarthritic rabbit knee joints.

In osteoarthritis the changes of the synovial membrane may seriously alter the oxygen transfer characteristics from the capillaries of the membrane to the synovial fluid and hence impede or deprive the joint cartilage of its sole source of oxygen. In the present study we have estimated the blood flow (Q), diffusing capacity (DO2) and oxygen consumption (VO2) of the synovial membrane in the chronic non effusive stage of experimental osteoarthritis. In 14 osteoarthritic knee joints we found a statistically significant increase in oxygen consumption, compared to previously reported results from normal joints, whereas the diffusing capacity and the blood flow were unchanged. The implication of this is that the partial pressure difference required to overcome the increased oxygen consumption was increased with a factor 4.3 and that the oxygenation of the joint cartilage was reduced with approx. 30 Torr.