Bones are held together in the joint socket by a network of ligament, tendons and muscles. Articular cartilage, a mix of collagens, proteoglycans and non-collagenous proteins, not only lubricates the joints allowing smooth movement of the bones, it also acts as a cushion and a sort of a shock absorber since it lines the bones. Cartilage is primarily composed of water (around 85%) which decreases with age (70%) leading to stiffness in the joints and difficulty in movement and ultimately arthritis. The cartilage can be damaged by joint injury, osteoarthritis, rheumatoid arthritis, avascular necrosis or osteochondritis dissecans. Injuries to the cartilage are most commonly observed in the knee joint, though they can occur in any joint. Joints with damaged cartilage are painful and stiff and have a restricted movement. Cartilage damage is a clinical problem of magnitude that needs serious attention since the number of people affected by arthritis is increasing and it is estimated that a quarter of the adult population will suffer from arthritis by 2020.
Since cartilage does heal itself and is not regenerated naturally by the body, the body produces fibrocartilage which fills the joint but can not handle the stress the joint undergoes with normal movements. Orthopaedic surgeons thus resort to various techniques to try and alleviate the pain and stiffness, which involve surgery and replacement of the cartilage. There are several techniques used by surgeons to try and solve the problem of cartilage damage. This could involve artificially stimulating the bone to produce more fibrocartilage or transplanting cartilage from an area where there is lesser movement, to the affected area. However all these procedures are at best experimental and have yielded mixed results in different people.
Experts in the field of orthopaedics and tissue engineers have been conducting research and trying to find a solution to the problem of cartilage regeneration for nearly a decade now. Scientists have discovered that cartilage cells can be stimulated to grow new tissue, under immense pressure skin to what one would feel half a mile below the surface of the earth. However this is in the experimental stage and scientists warn that it will be years before the procedure is ready to be tested clinically on humans. In yet another break-through finding by scientists, it has been discovered that a strain of mice are capable of regenerating cartilage naturally. Researchers are trying to identify the genes or proteins used for this process and find similar genes in human patients. Once again, this is only in the experimental stage and real treatment is still a distant dream.
answered by G R