arthroplasty

The prosthetic ball-joint to be used in a hip replacement operation is checked for size and shape against an X-ray of the patient's hip joint. Such a check not only ensures accurate fit, but gives the surgeon an indication of how much filing and reaming of existing bone material will be necessary during the operation.

Refashioning or replacement of a diseased joint. One of the most successful operations of this kind is total hip replacement.

Many advances have been made in recent years in the design, manufacture, and insertion of new joints, using alloys and hard-wearing plastics which are well tolerated by the body. Many patients with diseased hips have achieved greater mobility and relief from pain as a result of hip replacements. Other joints, such as the shoulder, knee, elbow, and ankle are now commonly replaced. Flexible silicone joints made in one piece can now be inserted into joints in the hand and are proving useful in treating deformities produced by rheumatoid arthritis, allowing pain-free movement, particularly in the joints at the base of the fingers.

In the US there are 123,000 hip replacements a year and 95,000 knee replacements (2006).