Osteonecrosis of the Femoral Head

To the Editor: We would like to commend Drs. Zalavras and Lieberman for their excellent review article on osteonecrosis of the hip.1 We do need, however, to highlight the massive disease burden that many less developed parts of the world are subjected to as a consequence of HIV and its management. The high incidence of osteonecrosis of the hip as a result of HIV infection is well documented.2,3 In the past, the limited lifespan of these patients meant that the orthopaedic management load was limited. The introduction of effective disease control measures, especially anti-retroviral therapy (ART), has resulted in these patients’ surviving relatively HIV-symptom free and with a near-normal life expectancy. This increased survivorship in respect of HIV infections, however, has allowed the disease-related sequela osteonecrosis to become common place. This is further compounded by the osteonecrosis’ resulting directly from the treatment with ART,4 in itself essential to keep the progression of HIV to AIDS at bay. At the Johannesburg, South Africa, Complex of Academic Hospitals, we have experienced a dramatic rise in osteonecrosis of the hip, usually in young people who are HIV positive and on ART. Fully 25% of all the hip replacements currently done at our hospitals for end-stage osteonecrosis are now due to HIV/ART. This additional burden on our stretched resources is over and above the routine demand for joint arthroplasties for degenerative and other joint disease. Actuarial calculations project that within 10 years, we may need to perform more than an additional 1,000 hip replacements for HIV/ART-related osteonecrosis at the Johannesburg Complex of Academic Hospitals alone.5 We are sure that the review by these authors1 would have been enhanced by some mention of HIV and ART in the etiology and pathogenesis of osteonecrosis of the hip. Dick van der Jagt, MBBch, FCS(SA) Orth Lipalo Mokete, MBBch, FCS(SA) Orth Jurek Pietrzak, MBBch, FCS(SA) Orth Johannesburg, South Africa The Authors Reply: We would like to thank Drs. van der Jagt, Mokete, and Pietrzak for finding our review excellent and for their important comment. We agree that there is an increased incidence of osteonecrosis in HIV-infected patients. As these authors report, the increased survivorship of these patients has led to an increased number of joint arthroplasty procedures and a considerable burden on available healthcare resources, especially in developing countries. However, a direct link between antiretroviral therapy (ART) and osteonecrosis in HIV-infected patients has not been established, and for this reason, we did not include this in the etiology and pathogenesis section. Several case-control studies evaluating risk factors for the development of osteonecrosis in HIV-infected patients have not shown an association with ART.2,3,6-9 Instead, they documented the significantly increased presence of already established risk factors, such as corticosteroid use,2,3,7,9 coagulopathy,3 hyperlipidemia,3,4 and alcohol consumption,9 in HIV-infected patients who developed osteonecrosis compared with HIV-infected patients who did not develop the disease. Our suspicion is that there is some type of association, but further study of this issue is needed to define it. Thank you again for highlighting the important problem of osteonecrosis in HIV-infected patients. A high index of suspicion for osteonecrosis in these patients may lead to diagnosis at an earlier stage and treatment with a femoral head-sparing procedure, thereby potentially decreasing the burden of the disease. Charalampos G. Zalavras, MD Jay R.