Why hip replacements fail
- Loosening — the implant loses its bond with the bone, usually from repetitive stress over many years.
- Wear — the bearing surfaces (typically a polyethylene liner) wear down, producing microscopic debris that can trigger bone loss.
- Infection — superficial or deep infection of the joint, which may present years after surgery.
- Dislocation — recurrent dislocation of the prosthetic ball from the socket.
- Fracture — periprosthetic fracture of the bone around the implant, usually after a fall.
- Metal reaction — adverse local tissue reaction to wear particles in certain bearing combinations.
Symptoms
Patients typically describe new or recurring pain in a previously well-functioning hip. There may be a change in walking pattern, a clunk or catch, or unexplained swelling.
Investigation
- X-rays — comparison with previous films is invaluable
- CT and MRI — for detailed assessment of bone, implants and soft tissues
- Bone scan — to identify loosening or infection
- Blood tests — inflammatory markers and metal ion levels where relevant
- Joint aspiration — when infection is suspected
Treatment
Some patients can be managed conservatively with monitoring and activity adjustment. When the cause is reversible (such as a worn liner), only the affected components may need to be revised. In more complex situations, revision hip surgery replaces some or all of the prosthetic components.