Apparently some change in the joint cartilage of older people allows or favors the formation of crystal deposits. It affects men and women equally. In a healthy joint , a firm, rubbery material called cartilage covers the end of each bone. Cartilage acts as a cushion, or shock absorber, between the bones.
Joint tissue is enclosed by a capsule.
The capsule is lined by a thin material called the synovial membrane. The membrane releases a slippery or sticky fluid, called the synovial fluids into the enclosed joint space. This liquid helps the joint tissues move smoothly and easily. The CPPD crystals, although first found in the joint cartilage, also can occur later in the synovial membrane and synovial fluid. This probably is a result of their release from the cartilage.