CD4 and osteonecrosis: Multiple studies show a growing incidence of osteonecrosis in patients with HIV, showing nearly three times the risk of the general population.40 One recent study revealed a strong association between high-activity antiretroviral therapy and development of osteonecrosis, although the authors caution that the association does not imply a pathologic role.40 Other studies have found no association between osteonecrosis and antiretroviral therapy (ART), citing instead association with alcohol, hyperlipidemia,41 or low nadir CD4 counts,42 although the mechanism is not well understood.