Joint replacements

The hip joint is a ball-and-socket joint, whereby the thigh bone (femur) forms a ball (the femoral head) that is embedded in the hip socket of the pelvic bone (acetabulum). The joint surfaces are covered with cartilage that allows the bones to move against each other smoothly. The joint is enclosed in a multi-layered capsule, whereby the innermost lining is formed by the mucous membrane. The fluid that it produces lubricates the joint, weakening the friction forces. At the same time, it nourishes the joint cartilage. The joint is held together mechanically by the firm capsule and a series of muscles and ligaments. This keeps the pelvis and thigh firmly connected while simultaneously ensuring effective mobility. As this is a ball-and-socket joint, almost all movements are possible. A well-developed and sturdy musculature is very important for the stability of the joint. This allows fluid movement even on uneven terrain and has a considerable influence on our posture. Even after a hip operation, sturdy musculature is necessary if the artificial hip is to function effectively. The more flexible and stretched the musculature is, the better the mobility of the artificial joint.