Ask the Doctors January 2005 Issue

Ask Dr. Marks: 01/05

I read recently about a hip-repair procedure called resurfacing. The article said the procedure requires less recovery time and reduces the chance of dislocation. Is it more effective than a total hip replacement?

Resurfacing arthroplasty has been around for a long time. Before the modern era of total joint replacement, cup arthroplasties were used to give a measure of pain relief to arthritis sufferers. The procedure involved a highly polished metal cup being placed on the femoral head. The results of the procedure vary from good to very poor; even the best cup arthroplasty did not compare to the results of the total hip replacement. The early cup arthroplasties were quickly supplanted by the vastly superior cemented total hip.

In the late 1970s a modern variation of the original resurfacing procedure was performed in a number of centers in the U.S. This procedure was called a double cup arthroplasty (DCA), and it was marketed as a conservative alternative to a standard total hip replacement. The concept was simple: The acetabulum (the cup part of the hip) was resurfaced with a high-density polyethylene component cemented into the pelvis. The femoral component was a polished metal cup that was cemented on a prepared femoral head. Double cup arthroplasties went on to fail in large numbers and were replaced by the current porous, in-growth total hip replacement.

We are once again seeing the resurrection of resurfacing arthroplasty as an alternative to conventional total hip replacement. The materials have changed with the use of newer, cross-linked plastics or metal-on-metal articular surfaces. The acetabulum remains a porous, in-growth shell, while the femoral component is usually cemented into place. It continues to have the same drawbacks as previous resurfacing arthroplasties. While it sounds conservative, it certainly is not conservative for the acetabulum. More aggressive reaming is necessary to accommodate the larger components. Bone loss on the pelvic side is also frequently a problem. On the femoral side of a double cup arthroplasty, bone reabsorption or avascular necrosis underneath the cup can lead to early failure.

Conventional total hip replacement gives excellent and predictable results. It is doubtful that the new type of resurfacing arthroplasties will find a place in the treatment of osteoarthritis. It is hoped that this new type of double cup arthroplasty will be thoroughly tested for a long enough period of time to assure both the patient and the surgeon that they are not subject to early failure, as was the case with their predecessors.

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I’ve taken methotrexate for several months to control my rheumatoid arthritis, but the bouts of upset stomach have become too much. I read that folic acid can counter-act the side effects of methotrexate. Can you tell me more about it?

Folic acid is used to counteract cytopenia (deficiency in white blood cells) and oral ulcers that are frequently seen in patients who take methotrexate. It does not help, however, to alleviate the gastric upset associated with methotrexate in pill form. Intravenous methotrexate can achieve the same anti-inflammatory effect, but without stomach upset. Unfortunately, production of injectable methotrexate in the U.S. does not meet current demand, making it difficult to get the injectable drug. If methotrexate cannot be tolerated in either form, the drug must be stopped and other medications considered.

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I’ve heard that some of the traditional factors that are believed to cause gout—excessive consumption of meat and seafood—are now being called into question. What’s the latest on this?

For many years, doctors have recommended that patients with gout avoid foods high in purine, such as alcoholic beverages, fish, seafood, shellfish, and meats such as bacon, turkey, and veal. Dietary management, however, can be very restrictive and of limited benefit. As a result, most patients do not comply with dietary management of their gout. For this reason, the focus of treatment today has shifted to the control of hyperuricemia (excessive uric acid in the blood) by medications and the use of non-steroidal anti-inflammatory drugs (NSAIDs) during gout attacks.