<prompt> A 30-year-old male HIV positive on antiretroviral therapy has pain in right hip region. Flexion, abduction and external rotation deformity of right hip for 2 months, what is the most likely diagnosis?Avascular necrosisTB hipTransient synovitisSeptic arthritis  <response>: b TB hip in HIVAVN hip in HIVIncidenceMore CommonLess CommonDeformityFABER-stage of synovitis may be prolonged on treatment, then subsequently with onset of arthritis - FADIRLimitation of abduction and internal rotation so initially position is adduction and external rotation opposite to movements limited and than subsequently with onset of arthritis FADIR Unilateral usuallyBilateral usually 