Every orthopedic treatment has its benefits and risks, but some advantages are unique to hip resurfacing.
Bone preservation is the most significant benefit of hip resurfacing and has several potential advantages to the patient. Because more bone is retained in the femur, should hip replacement become necessary at a later date, the patient has increased odds of success for the subsequent operation. Over time, any hip replacement may loosen or show signs of wear. In young, active patients, there is a high likelihood that more than one hip replacement operation may be necessary over the lifetime of a particular patient. When more bone remains after a revision (re-do) hip operation the chances of success for the procedure increase dramatically.
Another benefit of hip resurfacing is that it allows for a much larger femoral ball size, which supports greater stability in the hip joint and a lower risk of dislocation. The dislocation rate after hip resurfacing has been shown in some studies to be about 10 times lower than for a traditional hip replacement.
Due to the unique nature of hip resurfacing surgery, there are some risks and complications that can arise in addition to the general risks that patients face with any surgical procedure. Complications to be aware of with hip resurfacing include:
Metal ion toxicity
Modern hip resurfacing uses metal-on-metal bearings. Both the cap fitted to the femoral ball and the hip socket are made entirely of metal. Although metal construction dramatically reduces wear and tear of the components, it has been shown to disperse metal ions through the body. Cobalt and chromium ions can become measurable in the blood stream, though they have not been shown to cause cancer or any other disease in humans. Although the metal ions are measurable, no one knows what a safe level is. Generally, people with functioning kidneys are able to excrete the ions in their urine.
Because the bone of the femur is retained, it is possible to fracture it after hip resurfacing. Most fractures occur early in the post-operative period if too much weight is put on the leg too soon after surgery. Patients generally need 3-4 weeks on crutches after surgery to protect the femur from bearing too much weight and to give the body time to adapt to its new prosthesis. Current techniques and rehabilitation protocols have reduced the risk of fracture to less than 2%.
Any surgery working around the bone of the femur may cause pressure to be put on the nerves in the hip area. This may cause a transient weakness of some of the muscles of the leg in less than 1% of cases.