Increased incidence of osteonecrosis of the hip observed in HIV-infected children

Osteonecrosis, or avascular necrosis has been reported in HIV positive adults since the early 1990s. The incidence of Legg-Calve-Perthes disease (LCPD) – a paediatric disorder characterised by osteonecrosis of the capital femoral epiphysis – among the general paediatric population in the US is estimated to be 5.7 per 100,000 person years.

A report from the PACTG 219 group in the May issue of Pediatrics examined factors associated with LCPD in a group of 2014 HIV infected and 849 HIV exposed, uninfected children between April 1993 and September 2000 enrolled in this long term outcome study.

The investigators observed six cases of LCPD amongst the HIV positive children – showing an incidence rate of 34 per 100,000 person years – and no cases among the uninfected children. HIV infected children had a 4.8 fold (95% CI:56-10.4) increase in age adjusted incidence rate of LCPD compared with the general paediatric population.

None of the factors examined – CD4 count, birth rate, height for age and gender percentile and triglyceride levels – were statistically significantly associated with the development of LCPD in this group of children.

Although the number of children with LCPD in this cohort was small the investigators suggest that “our data indicate that the increased incidence of osteonecrosis of the hip observed in HIV-infected adults also occurs in HIV-infected children, and that clinicians should be alert to this diagnosis in HIV-infected children presenting with hip pain or limp.”

The authors explained that it was unknown whether LCPD is attributable to HIV, HIV-associated complications that could predispose someone to thrombosis, to antiretrovirals or to the growth abnormalities experienced by HIV-infected children.