Studies on cartilage formation XIX. Oxygen and glucose supply of the regenerating articular surface

Complete removal of the articular cartilage in dogs is followed by regeneration of the articular surface. At the site of the bone wound, granulation tissue develops, which later differentiates into cartilage. The O2 and glucose supply of the regenerating articular surface is ensured by the synovial fluid, by the large exposed surface of the medullary cavity, and by the capillary network of the granulation tissue. Oxygen and glucose supply of the articular surface in different stages of differentiation has been statistically analyzed. It is suggested that in the early stage of regeneration O2 supply comes predominantly from the capillaries of the granulation tissue. Later on, as capillarization regresses, the oxygen supply, originating from the synovia and medullary cavity, assumes a more important role. In the stage of cartilage regeneration an oxygen-deficient state can be supposed in the entire articular surface, but areas differing in oxygen supply may be formed owing to local differences (due mainly to the extent of vascularization and degree of generation of the subchondral bone layer). At the site of chondrogenesis, conditions allowing aerobic metabolism of cells with reduced O2 requirements seem to be ensured. Glucose supply deriving from the above-mentioned sources satisfies the highest glucose requirements of the cells in the regenerating articular surface.