What's hip in surgery may be wrong for you

There's great interest recently in hip resurfacing and in travel to India for this procedure. Some surgeons suggest that this is the preferred procedure for patients with arthritis of the hip joint, and there's criticism of the FDA for "delaying" approval of the hip-resurfacing device.

Both suggestions appear to reflect some bias and do not stand up to scientific scrutiny.

As an orthopedic surgeon and researcher with more than 22 years of experience in hip replacement surgery, I am always looking for new and improved procedures to relieve pain and disability in patients who have arthritis of the hip joint.

Total hip replacement has been available and extremely successful for over 30 years. This procedure and the uncemented prosthesis went through stringent Food and Drug Administration approval studies in the mid to late 1980s. They have proven to be successful for at least 10 to 15 years in the vast majority of patients. With minor variations, these designs are still used successfully in patients of all ages.

The premises for hip resurfacing are that there is a high likelihood of failure of modern total hip femoral component stems placed into the thigh bone, and that resurfacing is a more "conservative" procedure, that is, removes less bone than a standard total hip replacement.

These premises are not entirely correct, and may mislead patients.

Recent published results of uncemented porous-coated total hip replacement have shown that there is a 95 percent to 99 percent chance of success, even at 10 to 15 years after the initial surgery. In our research, the bone grows well into both uncemented titanium acetabular and femoral components and the success rate is 100 percent -- no prosthesis loosened at up to 10 to 15 years after surgery.

Some patients do wear out the plastic parts placed in the 1990s, but reoperation is required for only 5 percent to 7 percent of patients. These are generally very active, heavy men who were less than 50 years of age when the procedure was performed. For the past five years, an improved plastic bearing surface (cross-linked polyethylene) has been used with FDA approval and excellent success.

In addition, although resurfacing may save a larger portion of the proximal thigh bone, recent research from England showed that it removes more bone from the socket than standard hip replacement. This is particularly worrisome for the future. Many of the surgeons who have designed resurfacing prostheses have said they should be used in only a very limited and selected patient population.

The "ideal" resurfacing patient is a man less than age 50 who is not obese, does not have cysts (holes) in the hip ball and has a particular shape of the upper thigh bone. A recent English study showed that this is present in only about 10 percent of patients who need hip surgery. Even in half of these, the surgeons could not safely perform resurfacing due to local bone conditions.

Resurfacing should be performed only by surgeons who are very experienced in hip surgery, and even then studies have shown a very high rate of serious complications in the first 50 resurfacings performed by any one surgeon. There is a risk of fracture. In the hands of expert hip surgeons from California and England, the chance of revision/reoperation for failure of resurfacing is between 4 percent and 13 percent in the first seven years after surgery. Contrast that with the 95 percent to 100 percent chance of success at 10 to 15 years with standard total hip replacements.

The risk of other complications, blood clots, dislocation and bone resorption are not decreased with resurfacing compared to standard hip replacement. The complication of hip nerve injury and the presence of a squeaking or clicking noise of these metal-on-metal joints have been greater than standard hip replacements. The resurfacing procedures are associated with more blood loss, and a larger incision (with more muscle damage) is needed to perform the procedure.

Finally, those patients considering resurfacing must remember that cobalt and chromium metal particles are elevated in the bloodstream and urine for many years, if not forever, after the procedure. There is a chance of damage to other organs from these metal ions. Women who are considering pregnancy and all patients with metal-jewelry allergies or a history of kidney problems should not have a metal-metal resurfacing procedure.

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The FDA is being responsible in delaying the approval of hip resurfacing devices. Patients-consumers should be aware that the first two generations of hip resurfacing devices were approved in the late 1970s and early 1980s. After initial enthusiasm, these resurfacing procedures had a high rate of failure and were pulled from the market.

Patients with hip disorders that require surgery need to discuss their problems with someone who is experienced with hip replacement surgery and should seek a second opinion if hip resurfacing is recommended. At present, there is more hype and hope for resurfacing than there is available scientific literature to support its use.

(Paul F. Lachiewicz, M.D., is professor of orthopedics at the UNC School of Medicine in Chapel Hill.)