There are currently two basic surgery options available for replacing the diseased hip joint, a total hip replacement or a hip resurfacing operation. A total hip replacement, THR, has been the gold standard for many years. It is major surgery that often results in a long post-op recovery and often limits your activities depending on the type of hip device that has been used in the surgery.
A total hip replacement means that the top portion of your femur bone will be removed, the remaining bone will be drilled and a device with a long stem will be placed into the bone. The stem is secured with bone cement or secured with a press-fit depending on the technique chosen by the surgeon. A cup will be placed in the acetabulum of the hip to provide a pivoting surface for the ball of the femur device. If you ever need to have a revision, it is much more difficult to remove the stem from the bone after it has been in place for a number of years. The bone must be cut apart to remove the old stem. Revision surgery of a THR is again major surgery and often limits a person in their activities after the revision. There are many types of hip devices and they often dictate what activities are acceptable.
Resurfacing: Resurfacing involves removal and replacement of femoral head with a hollow metal hemisphere which fits into the acetabulum cup. This technique preserves the femoral bone, maintains normal femoral loading and stresses. The newer, large head Metal on Metal hip devices offer a person much more of a very active life style than the older, small metal and plastic hip devices.
Advantages of Hip Resurfacing
- Femoral head is preserved.
- Femoral canal is preserved and no associated femoral bone loss with future revision. Also, the risk of microfracture of femur with uncemented stem implantation is eliminated.
- Larger size of implant "ball" reduces the risk of dislocation significantly.
- Stress is transferred in a natural way along the femoral canal and through the head and neck of the femur. With the standard THR, some patients experience thigh pain as the bone has to respond and reform to less natural stress loading.
- Use of metal rather than plastic reduces osteolysis and associated early loosening risk.
- Use of metal has low wear rate with expected long implant lifetime.
Special Risks of Hip Resurfacing
- Lack of long-term track record. Current device has only been used for about 10 years. Despite known low wear rate, longevity and longterm effects of wear debris are unknown.
- For some surgeons, the procedure has a longer surgical time. The procedure requires somewhat more skill of surgeon. Because of this, a learning curve" has been documented where it is common for a surgeon to have more complications in his first series of patients.
Special Requirements of Resurfacing Patients
- Solid bone in femoral head to hold resurfacing component. A few cysts or slight AVN collapse may be acceptable.
- Healthy kidneys to process any blood-borne metal ions from debris products.
Contraindications for Hip Resurfacing
Patients with the following indications are NOT suitable for hip resurfacing.
- Active Infection
- Malignant Tumours
- Insufficient acetabular or femoral bone stock
- Poor bone quality (for example, osteoporosis, osteomalacia)
- Anticipated non-compliance of the patient, alcohol or drug abuse
- Decompensated renal insufficiency
- Known allergy to one of the constituents of the implant