Articular Cartilage Injuries

Damaged articular cartilage and removal of loose fragments

Damage to the surface cartilage increases the friction in the kee joint and decreases its shock-absorption ability. If large pieces of cartilage are floating inside the knee joint, particularly if they are attached to a bone fragment, the joint may lock. These “loose bodies” cause further damage to the joint surfaces and osteoarthritis, which will worsen with time. The aim of surgery is to smoothen rough edges of the articular cartilage and remove loose debris.

Techniques to restore articular cartilage defects:

Microfracture

This involves stimulating a reaction in the underlying bone which initiates a healing response and the development of a fibrocartilage to fill in the defect. This type of cartilage is different to the native hyaline cartilage and can be thought of like being a “scar” which fills in the defect and smoothes out rough or catching edges.

Cartilage Grafts

Small cartilage and bone plugs can be harvested from a non-weightbearing part of the knee and “packed” into the defect. The end result looks something like a “mosaic” which fills the defect.

A technique called autologous chondrocyte grafting involves removing cartilage cells from the damaged knee before sending them to a laboratory where they are grown in culture until they have multiplied into many cells. The cell-culture mix is then placed into the area of damage, resulting in resurfacing by the cells : open surgery is usually used. This second procedure requires an arthrotomy (an incision opening the knee) to gain access to the site that requires the graft. This treatment is usually confined to patients less than 45 years old and can be expensive.