Effect of increased knee joint pressure on oxygen tension and blood flow in subchondral bone.

We have investigated the influence of acute changes in the knee joint pressure of rabbits on the oxygen tension and the regional blood flow in the subchondral bone. The intra-articular pressure was increased by infusion of a sodium chloride solution into the joint cavity, and the associated change in the subchondral oxygen tension was measured by mass spectrometry. The mass spectrometer was also used to detect, qualitatively, changes in the regional blood flow. When the joint pressure was increased from the habitual level to 75 mmHg, the average subchondral oxygen tension was reduced from about 39 to about 30 mmHg and, at the same time, the regional blood flow was reduced significantly.