What is evidence on hip revision?
A The failure of hip replacements is multi-factorial. Most are due to aseptic loosening secondary to polyethylene debris generated at the articulating surface. This incites an inflammatory response and leads to loosening of the implants and bone loss. Other failures occur due to infection, instability, trauma and fractures.
In general, the failure of hip replacements in younger patients seems to be directly related to activity levels, and has led to a number of strategies to reduce wear in total hip replacements such as the use of ceramic, metal-on-metal or oxinium articulations.
An understanding of failure modes and regular follow-up has dramatically improved the prospects of revision surgery. There is no set maximum number of procedures.
Revision depends upon a number of factors including the patient's well-being, bone stock and the quality of the soft tissues around the hip.
Using modern techniques it is now possible to reconstitute the bone around the hip and successful results have been obtained in revision hip surgery both on the femoral and on the acetabular side so that bone has been reconstituted and a relatively normal/primary construct has been recreated.
Novel techniques such as ultrasound devices for cement removal, special burrs, fluoroscopy and laparoscopy have been developed to remove previous implants and cement without causing further bone damage.
Cementless, coated and modular components that bypass the previous fixation are now available.
The outcome of revision hip surgery is generally inferior to a primary procedure. However, when these cases are concentrated at specialist centres excellent results can be obtained.
Delaying primary surgery leads to poorer outcomes. Patients with severe arthritis should not be dissuaded from undergoing hip arthroplasty because of fear of revision surgery. Instead, hip replacement should be undertaken when quality of life begins to deteriorate, rather than waiting until it is severe.
Regular follow-up is then required. Once there is radiographic evidence of failure the implant should be monitored very closely and once there is clinical evidence, revision should be undertaken before there is significant bone loss.
Mr Fares Haddad is consultant orthopaedic surgeon at
University College London Hospitals