Resurfacing Hip Replacement Surgery
Hip resurfacing is a special type of Total Hip Replacement that replaces the two surfaces of the hip joint. As opposed to a standard Total Hip Arthroplasty (THA) where the femoral head is removed at the base of the femoral neck and a stem is inserted into the femoral shaft, a resurfacing operation removes only the damaged cartilage and underlying bony surface from the head or ball of the femur. This is then replaced or resurfaced with a metal spherical cap. The acetabulum or socket of the hip is replaced with a titanium shell as with a THA. The liner of the shell is a highly polished socket and the polished femoral cap articulates with their liner. The two surfaces form a Metal-on-Metal bearing (MoM). This is called a ‘Hard Bearing’. The best of these MoM bearings creates a hip replacement that has a low wear rate, a very good range of moment and is very stable due to the large diameter of the ball and socket joint.
The benefits of resurfacing need to be weighed against the historic issues of MoM bearings. The original MoM hips such as the Birmingham Hip Resurfacing have an excellent record of low wear. However, there have been many copies of the BHR since its release that have not fared so well. Subtle design changes and materials have created some resurfacing implants that wore out much earlier than expected. The metal wear that was created (ALL bearings will wear over time creating wear debris) was toxic to both bone and soft tissues. These hips had catastrophic failures creating major problems for patients. As resurfacing is usually recommended in younger more active patients, these failures were often disastrous for these patients, with major bony and soft tissue destruction, requiring complex revision and joint reconstruction, often with poor outcomes.
As such, MoM has fallen out of favour around the world, with only a few surgeons continuing to perform the operation, achieving excellent results using the few implants that have an high record of success.
Recently, however, new designs of resurfacing have been developed using ceramic on ceramic (CoC) as the bearing surface. This is also a hard bearing surface and is used widely in standard THA with excellent results. Ceramic wear debris does not cause tissue or bone damage. As such, the advantages of hip resurfacing is hoped to become available again without the risks associated with MoM wear.
These CoC resurfacings are in their infancy and are being trialled in many centres around the world. It will be a few years before trials are completed and the implants have proven themselves to be safe and be made available to the general public.
The Adept resurfacing, which has an excellent record is available at the Mater Hospital in Sydney, and If you are still interested in Hip resurfacing, Dr. Thornton-Bott will be happy to discuss this with you.