To assess the effects of total hip arthroplasty or any other treatment, for advanced stage of avascular necrosis of the femoral head in adults (Ficat III and IV), in terms of post-operative pain (Visual Analog Scale (VAS) /Harris Hip /Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) sub scores) (Bellamy 2000; Harris 1969), post-operative function (Harris Hip/WOMAC sub scores) and Short-Form 36 (SF-36) score (Ware 2000) as well as implant loosening, dislocation and revision.
Secondary, to determine the effect of age, sex, level of activity, type of implants used (cemented/ uncemented/ hybrid) and type of osteonecrosis (primary/ secondary) on these outcomes.