Cartilage (软骨, tulang rawan) is the smooth white covering of the bones (it looks like the flesh of a coconut) at all the major joints in the body. It allows joints to have two smooth and slippery surfaces to guide on. Furthermore, it functions to absorb the daily repeated shock and loads that the joints are exposed to.
Localised areas of cartilage injury in the knee often present as cartilage ulcers, and these can occur during sports, injuries, or just through the normal wear and tear processes of aging. They may result in symptoms such as pain on activities, swelling of the knee, or symptoms of locking or catching.
The diagnosis is made by a good history taking, clinical examination, and usually an MRI (Magnetic Resonance Imaging) scan of the knee. Sometimes, cartilage ulcers are seen during arthroscopy of the knee performed for other injuries such as meniscus or ligament tears.
Cartilage ulcers are classified by two main criteria - the size of the ulcer (area of cartilage involved in cm squared), and depth of the ulcer (surface roughening only, partial thickness, full thickness, or full thickness and involving the underlying bone).