The hip joint is made up of a ball (the femoral head) and a socket (the acetabulum). The bone of both the femoral head and the acetabulum are covered with a thin layer of smooth shiny cartilage. In most parts of the hip this is between two and four millimetres thick. It provides the low friction surface to enable the hip to move smoothly and easily, and also acts as a shock absorber between the two bone surfaces. This smooth cartilage that covers bone is called articular cartilage, and can be distinguished from the fibrocartilage of the labrum.
How can the articular cartilage be damaged?
As hips degenerate through use and age, the cartilage is gradually worn and becomes thinner and roughened. On scans or at arthroscopic surgery, is often the first sign of developing arthritis. Localised, full thickness defects sometimes occur as a result of structural abnormalities of the hip like FAI, or may also occur during of impact injuries.
How can articular cartilage defects be treated?
Small articular flaps, which may cause catching pain, can be trimmed during hip arthroscopy. New cartilage can be grown in larger defects by techniques such as microfracture or cartilage transplantation.