Metal on Metal Hip Resurfacing
Metal on metal hip resurfacing is a technique which has been developed as an alternative to standard hip replacement, with various advantages.
Hip resurfacing is indicated for patients with advanced osteoarthritis who are younger and more active than the typical clientele for hip replacement and so are likely to live longer than the life of the implant. Revision of a cemented hip replacement is a major procedure while conversion of a hip resurfacing to a hip replacement is much simpler should the need arise.
Hip resurfacing complications include the presence of metal ions in the body from wear of the metal surfaces on each other, although no evidence has appeared to show that this has any health implications whatever.
Hip resurfacing surgery involves the removal of a relatively small amount of bone from the socket and the head of the femur and the insertion of implants which allow two metal hemispheres to articulate with each other. The large size of the implant head (standard hip replacement size is much smaller than anatomically normal) allows hip resurfacing recovery to be a bit quicker in terms of mobility and return to normal activities. Patients are also able to participate sooner and more vigorously in hip resurfacing exercises with the physiotherapist.
The metal on metal technique allows the polyethylene wear debris problems of standard hip replacements to be avoided by hip resurfacing. NHS practice is mostly to use cemented hip replacement because the client group is predominantly elderly people with hip arthritis, but specialised centres may offer resurfacing to more active and younger patients to preserve bone and allow more vigorous activities.
One of the hip resurfacing problems is that there is not yet good research evidence that the implants last as well as standard hip replacement and this technique will not be fully accepted until this is established.