In this type of hip replacement the cup is similar to other types but the stem is different as it is not really a stem at all, but rather a larger ball that sits over the existing native femoral head (which is specially shaped using instruments to allow it to fit). This is different to conventional THR’s where the native head is cut off and a stem is placed into the top of the thigh bone (femur). Resurfacing replacement also differs as the ball is significantly larger than other THR’s (and is similar in size to the native femoral head) and both the ball and socket are made of metal, giving a metal-on-metal surface. The advantages of hip resurfacing are a lower wear rate of the articulation, a reduced rate of dislocation, bone preservation on the stem side and the ability of recipients of this type of replacement to participate in all sorts of activities some of which are usually not recommended for patients with conventional THR’s.
Resurfacing is technically more difficult to perform, and so is usually best performed by specialist hip surgeons. The decision to perform a hip resurfacing is also more complex than a THR and has to take into account a number of factors. Not all patients are suitable for this technique. It is also important that the resurfacing prosthesis used has a good track record and is implanted optimally.