Study reveals ‘unacceptably high’ hip resurfacing failure rates

Hip resurfacing – an alternative to hip replacement often recommended to younger patients – is prone to early failure in many instances, and should not be used in women, according to a study led by the University of Bristol.
The observational study, conducted on behalf of the National Joint Registry for England and Wales, examined data from 434,650 hip operations undertaken between April 2003 and September 2011, of which 31,932 (7.3 per cent) were resurfacings. The research looked at how many resurfacing implants failed in the first seven years after surgery and whether the head size of the implant affected failure rates. Patients with resurfacing were also compared with those who had undergone hip replacement with other bearing surfaces.
Hip resurfacing is similar to total hip replacement, except the femoral head (the rounded top section of the thigh bone) is not completely removed. Instead, the superficial bone is removed and replaced with a metal cap. Hip resurfacings always have metal-on-metal bearings, whilst total hip replacements can have a variety of bearing options, such as ceramic, metal, or plastic. Resurfacing is often offered to younger patients as an alternative to hip replacement, but is also commonly used in older patients.
The researchers found that the use of smaller head sizes was linked to higher failure rates and in most cases, resurfacing implants failed more quickly than other bearing surfaces. The only exception to this was for men with a large (≥ 54mm) femoral head, who showed comparable rates of implant success to those who had undergone total hip replacement. This group constituted only 23 per cent (5,085) of the total resurfacing operations in men during the period studied. Women who underwent hip resurfacing experienced particularly poor implant survival, with failure rates up to five times higher than other bearing surfaces.
According to Ashley Blom, Professor of Orthopaedic Surgery in the University