The articular cartilage of the joint is the bearing surface which covers the end of the upper bone (femur) and lower bone (tibia) in the knee as well as the back of the kneecap (patella). This is a very hard covering which in childhood has the ability to regenerate to a degree but after full growth any damage to the articular cartilage represents a potential problem.
Sometimes this covering is damaged by injury which can leave a loose fragment free in the knee joint or alternatively may leave an area of mobile joint surface. Damage to the articular cartilage is often associated with swelling in the joint and pain on movement with very similar symptoms to those of a meniscal (cartilage) injury.
Initial treatment is aimed at settling symptoms using a combination of rest, ice, compression and elevation (RICE) followed by exercise which may be all that is required. If symptoms persist, however, further investigation is required.
Articular cartilage damage cannot be identified using an x-ray and an MRI scan is the investigation of choice to both identify the size of articular cartilage damage, identify whether there is a loose fragment in the joint as well as identifying any damage to the underlying bone.
Treatment for articular cartilage damage is dependent on the size of the damage and symptoms you experience. For small areas of damage giving significant symptoms removal of any loose flap of articular cartilage followed by microfracture (making small holes of the underlying bone) is performed to stimulate the formation of a scar tissue patch made from fibrocartilage which will bind together the surface. Larger areas of damage may require transfer of articular cartilage to fill the defect.
Generally this treatment is carried out using arthroscopy. Following microfracture it may be necessary for you to put partial weight through your knee which requires crutches whilst healing occurs.