Hip Joint Resurfacing

What is hip resurfacing?

Figure 1

Hip resurfacing is a type of artificial joint replacement used for the treatment of severe arthritis.  As an alternative to total hip replacement, it has become increasingly popular over the last ten years with excellent results seen.  However it is not suitable in all cases.  In this practice hip resurfacing is performed with the aid of computer navigation, decreasing the risk of component malposition, a common cause of early failure.

How is it different to total hip replacement?

In Total Hip Replacement (THR), the ball and socket of the hip joint are replaced. The femoral head is removed, and a stemmed component is placed into the central part of the upper thigh bone (see Figure 1). Hip resurfacing is similar although instead of removing the femoral head completely, only the damaged cartilage and a small amount of bone is removed, and a metal cap is placed on top (see Figure 2).

 

What are the advantages of hip resurfacing?

Figure 2

The main advantage of a hip resurfacing compared to a total hip replacement is preservation of bone at the top of the thigh bone (see Figure 2). If further surgery is required in the future for loosening of the artificial joint replacement, preserving this bone makes the revision surgery less complex, shortening the recovery time and improving the durability of the second operation. Preserving bone is therefore most important in younger patients with higher activity demands, who may potentially outlive an artificial joint replacement of any design. Hip resurfacings utilise impact and wear resistant bearing surfaces, suitable for higher grade activity demands. The incidence of dislocation after hip resurfacing is reduced compared to total hip replacement.

 

 

 

 

What are the disadvantages of hip resurfacing?

Hip resurfacings can fail in ways which are not seen with a total hip replacement. Preservation of the  bone at the top of the thigh may result in weakening of this bone and result in a fracture (bone break) or collapse. This complication occurs in approximately 2% of resurfacings. Fractures usually require further surgery, and often involve revising the resurfacing to a total hip replacement. In addition to the risk of fracture, resurfacings are only available with Metal-on-Metal (MoM) bearing surfaces. While MoM bearings have a very low wear rate and are impact resistant, there are theoretical risks associated with this type of artificial joint replacement. Should a MoM bearing be recommended then the advantages and disadvantages of this implant will be discussed with you in detail.

 

Who is suitable for hip resurfacing?

Figure 3

Generally, the ideal candidate for hip resurfacing is a male patient less than 60 years of age with high activity demands and severe osteoarthritis of the hip.

 

Who is unsuitable for hip resurfacing?

Patients over the age of 65, particularly females, are generally better managed with a total hip replacement. Patients with arthritis due to hip dysplasia (shallow hip socket) or avascular necrosis are at higher risk of implant failure if treated with hip resurfacing.

 

Are there alternatives similar to hip resurfacing?

Yes. There are alternative procedures available similar to hip resurfacing which may be considered. These  include a ‘microplasty’ total hip replacement (short femoral stem) or a ‘Birmingham Mid-Head Resection’ (BMHR) arthroplasty. These will be discussed further if required.