A joint is composed of two or more bones which articulate or move around each other
in a highly controlled and specific way. In order to allow smooth gliding and pain-
When some of this cartridge is crushed, damaged or knocked off the underlying bone, an articular cartilage defect has been created.
This is quite distinct and different from the wear and degeneration that occurs in
this articular cartilage over many years. Long-
In the strictest sense, these articular defects are secondary to direct/indirect
damage caused by a specific injury. Some defects can occur as a result of repeated
minor injuries, but this article will deal with those so-
Primarily, they represent a significant level of injury that affects tissues which are essential to normal function. Also, the mechanism by which articular defects are created, is often associated with other injuries within a joint, for example the rupture of a ligament, fracture, or torn meniscus.
The management of articular cartilage defects continues to pose significant challenges for the orthopaedic surgeon. Loss of the protective cartilage which lines the ends of the bones exposes the underlying bone. Over time, this creates changes which lead to the development of osteoarthritis. In the short term these defects may vary from no symptoms to significant pain and disability.
In the long term, the development of osteoarthritis creates a significant level of disability which requires treatment in its own right.
Techniques such as joint replacement are only suitable for certain age groups. What do we do when osteoarthritis occurs in younger and more active? By far and away the best approach would be to prevent secondary arthritis by reconstructing the cartilage defect however this is far from simple. Articular cartilage is a highly specialised tissue. It possesses no blood or nerve supply and so normal healing processes do not take place. The body attempts to repair these defects by providing a cartilaginous scar tissue however, this scar tissue, or fibrocartilage, is not as resilient as normal articular cartilage. For small defects it may be sufficient but for larger defects, the fibrocartilage tends to break down with the return of pain and other symptoms.
One recognised surgical technique is to stimulate the body’s own response to produce scar tissue by drilling multiple holes into the base of a defect. This causes bleeding and initiates a healing process and appears to be quite satisfactory for small defects but does not work particularly well for larger defects and still carries a risk of breakdown.
Transplantation of chunks of cartridge requires the underlying bone to be taken from
the donor site. Multiple small chunks are moved from one part of a joint to another
and the defect filled much as one would do if creating crazy paving. This so called
Mosaic plasty can produce more solid long-
The last decade has seen developments in the production of articular cartilage grown from the patient’s own cells. A small sample is harvested and the cells are grown in laboratory and then returned to the patient at a second operation. The cells are then implanted into the defect and held there with a biological skin until the graft has taken. This has produced some impressive signs of regeneration of cartridge not previously achieved. Even so, despite the fact that this technique creates cartilage which is more like normal articular cartridge, it is still not quite as strong. Quite often the surgery would have to be performed as an open procedure which itself carries some degree of disadvantage for the patient.