Hip Resurfacing and Orthopaedic Surgery
Overview of Orthopaedic Hip Surgery
Metal on metal articulation is not a new concept, but early orthopaedic hip treatments such as those by Mckee and Farrar were hindered bys the unsatisfactory engineering and materials technology available at the time. In the 1990’s, Derek McMinn and colleagues took a bold step in hip resurfacing and reintroduced the concept of the metal-metal articulation, releasing the McMinn resurfacing. This went through a number of design changes such as uncemented heads etc, before the Birmingham device was settled upon. This and it’s sister implant The Adept hip, are the longest serving hip resurfacing devices with the longest pedigree on the market today (over 21 years).
The resurfacing procedure has been somewhat tarnished by copy implants which through various design changes (in most cases very well meaning) managed to reduce the success of the procedure. The Adept and Birmingham remained true to the original design and have remained the implants of choice with the best results in the National Joint registry for resurfacing devices. It was recently announced that the Birmingham will be discontinued which means that the Adept is the only resurfacing currently available going forwards. We are also waiting very excitedly for its sibling Ceramic ReCerf implant to be released (May 2025) so that we can offer this device to female patients at long last.
Generally metal resurfacing is reserved for young (elderly have a higher failure rate due to weaker bone stock), male (female patients have an even higher failure rate- this is national guidance) and active patients who would benefit from its functional outcomes and resistance to dislocation. The ceramic implants will finally allow us to include female patients in our offering. I am happy to discuss in detail and at length the various risks and benefits of the device for each and every patient considering it as an option.
Benefits of Hip Resurfacing
Hip resurfacing provides a bearing of similar size to the patient’s own hip. This reduces dislocation rates and patients report the hip feels more ‘normal’. This may also be due to the fact that the procedure doesn’t ‘instrument’ the femur as with a normal hip replacement, thereby reducing the tissue damage and inflammatory substances released.
Resurfacing patients often report a quicker post-operative recovery in the short term, although function at one year onwards with a modern THR is probably similar.
The metal-metal bearing surface is also very durable. Hip resurfacing treatment has, however, had issues with regards to the release of metal ions as described below. We plan to offer ceramic resurfacing imminently as an alternative for higher risk patients.
Suitability for Hip Resurfacing Treatment
This is not a device for all patients, as complication rates rise for certain patient groups. Active males with osteoarthritis of the hip are most suitable for this treatment and seem to have the best results, with failure rates around 0.5-2% in the short term. Unfortunately being older and being female are both relative risk factors. Females have reduced bone mass which worsens after hormonal changes post-menopause. They also have smaller hip sizes. This has important ramifications for the lubrication within the hip, and therefore rates of wear. The results of metal hips in female patients has been poor and we’ve been stopped from offering resurfacing. HOWEVER, we are expecting the imminent release of a ceramic resurfacing (hopefully May 2025) which will fill this void. Extensive clinical trials have shown that this device provides excellent short term results equally in male and female patients. It could been a gamechanger!!
The Hip Resurfacing Procedure
The approach varies, but the majority of UK specialist orthopaedic hip surgeons, Mr Eastaugh-Waring included, use a posterior approach to the hip. This preserves the muscle function of the hip joint to allow maximal function post-operatively. Hip resurfacing procedures can cause a scar that may be slightly larger than a standard hip replacement as it is necessary to work around an intact femoral head.
The acetabulum (cup) is prepared as for a hip replacement and an uncemented metal shell inserted with a friction fit. The worn surface of the head is then carefully reshaped and a metal cap applied with cement.
Post-operatively, most patients will be able to fully weight bear the following day. Discharge from hospital is usually within one to two days.
Complications in Hip Resurfacing Treatments
Most large series report an early failure rate of resurfacing at around two to four per cent. The commonest cause is avascular necrosis (loss of blood supply) and/or femoral neck fracture. This risk is reduced by avoiding impact of load carrying for the first three months, and if it does occur can be remedied with transfer to a hip replacement.
The second cause of failure specific to metal-metal joints is known as ALVAL (aseptic lymphocyte-derived vasculitis and associated lesions). This is, as yet, still unclear and it is being studied in detail, but seems to be an inflammatory reaction by the body’s immune system. The condition causes ongoing pain, often steadily worsening, and can be difficult to diagnose on simple X-rays. An experienced orthopaedic hip specialist who is aware of the condition will arrange a specially designed MRI sequence and this, in association with a fluid sample from the hip replacement, should yield the diagnosis. The treatment is also to replace the metal bearing with a ceramic on polyethylene hip replacement.
Rates of ALVAL vary between patients. One study from Oxford, analysing over a thousand hip resurfacings, reported ALVAL in 0.5% in young males, but up to 25% in females. Causes are uncertain, but may relate to the smaller hip size and less than optimal lubricating regime. Stephen will be offering ceramic resurfacing for female patients upon its release (hopefully May 2025). Bristol will be only one of 6 sites nationally to offer this procedure initially given Stephen’s experience and expertise over many years of using the metal implants.
If you wish to book an appointment to discuss hip resurfacing treatments please get in touch via the contact page.