In this section you will find answers to the most frequently asked questions we receive regarding hip resurfacing at the Joint Replacement Institute.

A. Hip resurfacing is a bone-conserving alternative to conventional total hip replacement (THR). Unlike THR, hip resurfacing does not involve the removal of the femoral head and neck nor removal of bone from the femur. Rather, the head, neck and femur bone is preserved in an effort to facilitate future surgery should it be necessary and to enable the patient to take advantage of newer technology or treatments in the future. Refer to the interactive animations on this website for detailed descriptions of both hip resurfacing and total hip replacement.

The current generation of hip resurfacing devices utilize a metal-metal bearing rather than the metal-polyethylene bearings that were utilized in the 1970’s and 1980’s. Metal-metal bearings have demonstrated a much lower wear, minimal  bone loss and inflammatory tissue reaction about the hip joint as compared to metal-polyethylene bearings.

Hip resurfacing is anatomically and biomechanically more similar to the natural hip joint, resulting in increased stability and flexibility. Further, dislocation risk is virtually eliminated. Higher activity levels are typically achieved with less risk than with a THR should a revision ever be necessary.These benefits are realized because the head diameter that results from resurfacing is very similar to the patient’s normal head diameter and these larger head sizes are typically much larger than the femoral balls utilized in conventional THR. It should be noted, however, that THR with larger femoral balls is now available and these devices can also result in a high degree of stability with minimized risk of dislocation.

A. Prolotherapy targets ligaments and tendons and so would not be effective with osteoarthritis of the hip joint.

 

A. Unlikely to be of any benefit for OA of the hip because most are caused by an anatomical abnormality.

 

4. Q. What is the difference between metal-on-metal hip resurfacing and femoral head or “hemi” resurfacing?

A. Hemi-resurfacing (Femoral head only) is indicated for patients with early stage (i.e., stage II, stage III/early stage IV) avascular necrosis (AVN) in which the articular cartilage is in relatively good condition. In other words, the hip is not yet arthritic. Therefore, the acetabulum is not replaced. There are several hemi-resurfacing devices that are commercially available (i.e.,  FDA approved). The procedure may be indicated for some patients under ~30 years.

Metal-metal hip resurfacing, on the other hand, is indicated for hip arthritis in which the articular cartilage has deteriorated and, therefore, the acetabulum (socket) must be replaced. See Directors’s message for information on Status of FDA approval.

 

A. No. Resurfacing actually takes less bone on both sides. The same cup can be used for both so if a revision is required due to problems with the femoral cap, the acetabular cup can usually be retained.

 

6. Q. How do the chances for long-term hip dislocation compare between hip resurfacing, large head metal-on metal, large head ceramic, and typical metal on plastic THR?

A. Provided that the surgery is well done and the components are optimally positioned, the larger the ball size the more stable the joint will be. The ball size will be reduced with any 2-part socket and the risk of instability increased. The risk of dislocation is therefore greater with ceramic bearings, then polyethylene, then metal-on-metal, in descending order. A 40mm or greater ball size provides the best stability.

 

A. A surgeon who is experienced in hip resurfacing can determine if you are an appropriate candidate for the procedure following an examination and a review of x-rays. However Dr. Amstutz has reported improved short to mid-term results even in hips with bone defects1 while other surgeons have been reluctant to resurface unless the bone quality is good2. Initially, hip resurfacing was indicated for active adults in whom additional surgery may be required within their lifetime based upon their age, activity level and other factors. However our up to 11+ year results suggest that life time durability may be possible and therefore our age and other indications are expanding.

 

A. The role of the DEXA scan, or even CT, is not clear. DEXA does not seem to correlate with the prevalence of femoral neck fracture in HR. Statistically, active older patients do well with resurfacing. Unless there are other obvious contraindications, the final decision must be made by a surgeon who has experience and confidence in performing the procedure.
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9. Q. Can hip resurfacing be done in the case of protrusion?

A. Yes, it can work very well and does not present undue difficulty. The Conserve®Plus system has several sockets to use. We have resurfaced many.

A. While it is true that large cysts did correlate with higher failure rates in the very early HCA series, with improved surgical technique, the failures have virtually been eliminated in the HCA experience, expanding the indications (See resource library).

A. Most surgeons will perform only when the bone quality is good while other accept up to 30% of the femoral head being defective. However HCA has accepted much larger defects in young patients but surgical technique is critical. The size of the bone, the size of the defect, the quality of the bone, the patient's weight and their intended activities all play a role in the decision making process. A surgeon with little hip resurfacing experience would be wise to choose patients without large cysts.

 

12. Q.  When and why does HCA recommend cementing in the stem?

A. Cementing of the metaphyseal stem is useful in cases with known risk factors for early failure (i.e. femoral component size smaller than 48mm and presence of femoral defects greater than 1cm) but is unnecessary in hips of large size with good bone quality. Cementing the metaphyseal stem is an effective way to increase the area of the bone-cement interface and enhance initial fixation of the component.

 

A. There is a substantial learning curve with hip resurfacing. You would want a surgeon who was quite experienced with THR and has had good results with resurfacing. Excellent technique can only be developed by doing the surgery regularly. There is no substitute for experience. I (HCA) continue to fine-tune my technique after several thousand resurfacings.