A study of nutritional transport in a synovial joint

AbstractAged articular cartilage has no other means of nutritional transport to the cartilage cells except the inbuilt mechanism of interstitial fluid exchange in between the cartilage and synovial fluid. The secreted nutrition from blood mixes well in the synovial fluid and during articulation it enters into the cartilage where it meets with the cartilage cells. The local variation of the permeability of the cartilage, therefore, plays a very important role in the whole mechanism. Analytically the problem is formulated as a two region diffusion and flow model: flow and diffusion in between two approaching cartilage surfaces and within the porous cartilages. The solution of the coupled mixed boundary value problem could only be obtained for a few particular cases. It has been observed that the increased permeability at the surface does not allow nutrition to the cells in the deeper region and they die out. In case of diseased joints the nutritional transport is very difficult owing to increased rigidity or local variation of permeability within the cartilage. The paper further concludes that for low molecular weight solutes, the phenomenon of nutritional transport is diffusion dominated whereas for large molecular weight solutes, it is dominated by mechanical pumping action