There is a constant wear-out and replacement activity of the molecules that make up the articular cartilage matrix. Specialized cartilage cells, known as chondrocytes, are responsible for maintaining this matrix. Chondrocytes decrease in number as we age and can be damaged by repeated overuse (microtrauma) or single, high force impacts (macrotrauma). Once chondrocytes are damaged or lost, the surrounding cartilage matrix gradually degenerates and defects appear. Without intervention, the body is not able to repair these defects. In the majority of cases, there is very little cartilage tissue at the defect site available for repair; therefore, the cartilage must be restored or artificially replaced.
Open Reduction/Internal Fixation (ORIF)
Occasionally, a piece of cartilage may be displaced from the underlying bone and adjacent cartilage; either as a flap or loose fragment. In some instances, it is possible to reattach the loose cartilage with sutures or screws. This is known as open reduction (the joint must be surgically opened to reduce the cartilage fracture), internal fixation (the fixation method does not protrude through the skin).