AAHKS members asked about osteonecrosis of the femoral head

How do you treat osteonecrosis of the femoral head?

That was the question the American Association of Hip and Knee Surgeons (AAHKS) posed to its active members. A 16-question survey elicited the evaluation and treatment preferences for this rare, but devastating, condition.

The 753 AAHKS members were asked to respond to hypothetical clinical scenarios based on the Steinberg Classification system, and 403 (54 percent) did so.

Although no clear consensus emerged, the most common treatment for postcollapse osteonecrosis (Steinberg stage-IIIB, IVB, V, and VI) was hip replacement. Survey respondents selected core decompression for patients with symptomatic, precollapse osteonecrosis (Steinberg stage-IB and IIB). Treatments such as nonsurgical management, osteotomy, vascularized and nonvascularized bone grafting, hemiarthroplasty, and arthrodesis were less commonly used.

After the results of this Level 5 therapeutic study had been compiled, Annie Hayashi, AAOS Now Senior Science Writer, discussed them with two of the authors and three other AAHKS members: Michael A. Mont, MD, director of joint preservation and reconstruction at the Rubin Institute for Advanced Orthopedics; Aaron G. Rosenberg, MD, specialist in hip, knee, and joint-replacement surgery at Midwest Orthopedics at Rush Medical Center; Jay R. Lieberman, MD, director of the Musculoskeletal Institute and chair of the Department of Orthopaedic Surgery at the University of Connecticut Health Center; Brian J. McGrory, MD, specialist in surgery of the adult hip with the Maine Joint Replacement Institute; and William B. Macaulay, MD, director of the Center for Hip and Knee Replacement at Columbia Orthopaedics.

Ms. Hayashi: Why has treatment of early-stage osteonecrosis of the femoral head continued to be so controversial?

Dr. Mont: It is a rare disease and, as the survey points out, there are only 10,000 to 20,000 new cases each year. Many orthopaedists may see a case of osteonecrosis of the femoral head only once every 2 years. When an orthopaedic surgeon does see a case, classification is more difficult than the survey suggests. It is not always obvious what a pre- or postcollapse lesion is; whether it does or does not have a crescent sign, especially when you haven’t seen one for a few years. We don’t have treatments for the early stages of this disease that can guarantee 99 percent success.

Dr. Rosenberg: Classification systems have changed over time, so it may be difficult for practitioners to keep abreast of all the studies and compare them to patients’ radiographs. There is also a bias against treatments with lower success rates, even when no other better options exist, making some of these treatments controversial.

Dr. Lieberman: We don’t know the etiology of the osteonecrosis. It is the end point of multiple diseases. It could be steroid-related, secondary to sickle-cell disease, or the result of trauma. It’s very hard to treat a disease when we don’t know the cause. Because we don’t know the etiology, you see a number of management strategies in the early stages of the disease.

Dr. McGrory: One of the treatment controversies is the seemingly contradictory data on how to treat different lesion sizes—not only how to treat but also when to treat. It can be confusing for the general orthopaedist.

Dr. Macaulay We need to do randomized, controlled trials on these patients, to study the natural history of the disease, and to look at nonsurgical management, especially in the early stages.

Ms. Hayashi: What research is being done to understand the etiology of the disease? What’s going on in the field right now?

Dr. Mont: Some studies are examining the genetic basis and the enzyme defects that may trigger this disease in patients. The best reason for doing these studies would be to try to predict which patients, with certain associated risk factors, will get the disease. Who are the 10 percent of the patients who are truly at risk? That’s where a lot of future work will go and that’s why it’s important to try to understand the etiology.

Dr. Rosenberg: If significant advances are made in the next 10 years in these areas, many of the issues that are still controversial will become moot as other treatment modalities become better recognized or pharmacologic treatment becomes a standard of care. I think one of the surprising results of the survey was that few surgeons are using any of the currently recommended pharmacologic medications.

Ms. Hayashi: What else surprised you about the survey results?

Dr. Macaulay: I was surprised by the large numbers of patients who were asymptomatic but still had surgery. This is clearly supported in some of the literature but is hard for some people to understand.

Dr. Lieberman: I was surprised by that, too. Hernigou’s recent paper showed that in all patients with small lesions, the femoral head would eventually collapse, but the vast majority of those patients had had at least 6 months of symptoms. I think it is very difficult to make a patient better who is asymptomatic.

Dr. McGrory: The editors of the Journal of Bone and Joint Surgery asked Marvin E. Steinberg, MD, to comment on our survey. He thought that prophylactic treatment should not be withheld from the asymptomatic patient. I think his point was that the hypothetical patients in the survey had moderate-to-small lesions.

Dr. Mont: I was also surprised that 15 percent of orthopaedic surgeons who perform arthroplasty still use hip fusion—and that 11 percent have used arthrodesis in the last 5 years.

Dr. Rosenberg: I remain one of the few people who think that there may occasionally be an indication for hip fusion, particularly in a very young male patient. I particularly want to avoid hip replacement in an adolescent male patient. My opinion, however, is not supported by any evidence-based research.

Dr. McGrory: I was very surprised by how many surgeons would offer resurfacing arthroplasty, despite published results in Europe that show traditional arthroplasty is better than resurfacing for osteonecrosis cases.

Dr. Lieberman: I was reassured that the vast majority of surgeons were not offering core decompression or femoral-head preserving procedures for patients who have a collapsed femoral head.

Dr. McGrory: Even when the surgeons could see the crescent sign, which is the earliest form of collapse, they did not recommend core decompression. I was reassured that they made that distinction.

Dr. Mont: I was surprised by the small number of patients who were offered vascularized bone grafts. Maybe a small group of orthopaedic surgeons are doing vascularized fibular grafts and seeing a larger number of osteonecrosis patients. We don’t really know how many cases each respondent performs to know true treatment numbers. I think the number of patients receiving vascularized fibular bone grafts is actually higher than what is reflected in the survey.

Dr. Rosenberg: The number of patients offered vascularized fibular grafts was quite low. In the IIIB group, it was only 3 percent.

Ms. Hayashi: What changes do you anticipate in the overall treatment of osteonecrosis during the next 10 years?

Dr. Macaulay: In the next 10 years, I would like to see more research into the etiology of osteonecrosis of the femoral head and more about the natural history of this disease.

Dr. Mont: In 10 years, we will be able to determine a patient’s genetic predisposition to osteonecrosis through a blood sample and we’ll know the risks of putting that patient on steroids. In some respects, this may become be a preventable, nonsurgical disease that can be treated by a rheumatologist and internist with bisphosphonates, statins, and other pharmacologic treatments. We may be still be using core decompression or drilling for early-stage disease, but we’ll have ways to treat more advanced cases less invasively with bone grafts and bone morphogenic proteins. We will have more predictable ways to treat patients with early-stage disease, and we won’t see as many patients with late-stage disease.

Dr. Lieberman: I think stage I treatment will be a combination therapy including agents that inhibit osteoclast activity and stimulate bone repair. If such therapies can be developed, we may be able to eliminate many of the surgeries. We need to learn how these medications influence bone remodeling throughout the body.

Dr. Rosenberg: That requires money for research, and competition for resource dollars is fierce. Because osteonecrosis of the femoral head is a relatively rare disease, it doesn’t have a big national association to do fundraising. Not a lot of research dollars are dedicated to it.

Disclosure information on the participants is available at www.aaos.org/disclosure

Annie Hayashi is senior science writer for AAOS Now. She can be reached at hayashi@aaos.org

References:
McGrory BJ, York SC, Iorio R, et al. Current Practices of AAHKS Members in the Treatment of Adult Osteonecrosis of the Femoral Head. J Bone Joint Surg Am, 2007;89:1194-1204. (www.ejbjs.org)

Hernigou PH, Habibi A, Bachir D, Galacteros F. The Natural History of Asymptomatic Osteonecrosis of the Femoral Head in Adults with Sickle Cell Disease. J Bone Joint Surg Am, 2006;88:2565-2572. (www.ejbjs.org/cgi)

Steinberg ME, Commentary on Current Practices of AAHKS Members in the Treatment of Adult Osteonecrosis of the Femoral Head by McGrory et al. J Bone Joint Surg Am, 2007;89:1194-204. (www.ejbjs.org)