HIV-infection can increase the risk of acquiring avascular necrosis (AVN) of bone (otherwise known as aseptic necrosis) by more than 100-fold over the non-infected population (27). In addition to HIV infection itself, other risks include taking ART, smoking, hyperlipidaemia, corticosteroid use, vasculitis and anti-phospholipid syndrome (28). AVN mainly affects the femoral head but can occur in the knee (femoral condyles and tibial plateaux), humeral head, talus and elsewhere. There may be no symptoms especially early on and AVN of the hip, for example, can be an incidental radiological finding. Later, however, there may be progressive groin pain; at first just felt when weight-bearing, but later occurring at rest. It is best diagnosed by magnetic resonance imaging. Treatment remains controversial and many pharmacological and non-pharmacological modalities have been trialled. Pain control is important and non-operative therapies are preferred, though surgery is often needed. Joint replacements have been found to be necessary at a younger age in HIV-infected patients compared to non-infected patients (61% vs 8% of 22-50 year-olds) (29).