Sometimes the best way to relieve pain and restore function to a joint is to replace all or part of it with a prosthesis (an artificial joint). Prostheses are intended to restore function to the joint and relieve pain associated with arthritis, other chronic conditions, or traumatic injury.

Prostheses are designed to move like a regular joint. They are made of durable plastic and metal parts that fit together snugly but glide smoothly (as opposed to the painful friction associated with the worn cartilage of arthritic joints). The pieces are shaped like the structures they replace - for example, the damaged bones in a ball-and-socket joint of a hip or shoulder are replaced with a metal ball and plastic socket. They are held to the surrounding bone either with a locking mechanism or with a special bone cement.

The length and difficulty of recovery depend on the location of the joint replaced as well as the patient's age and overall health. Hip or knee surgery typically requires temporary use of a cane or walker. Some pain and stiffness following surgery is normal. Gradually, the weakened muscles regain strength and flexibility as the patient becomes accustomed to using the joint. The physician will discuss when it is safe to return to any athletic activities. Once in place, prostheses usually perform well for up to a decade or longer.