Direct Anterior Total Hip Arthroplasty (THA), in Versus Outpatients : A Prospective Monocentric Study in Rennes University Hospital.

Inclusion Criteria: * Unilateral primary total hip arthroplasty for hip osteoarthritis, primary or secondary osteoarthritis (dysplasia or post-traumatic) or osteonecrosis * Good enough understanding of outpatient management and patient adherence to post-operative instructions * Sufficient patient complicance to medical orders * Living and hygiene conditions, at least, equivalent to the ones the hospital provides * To be of age * Non opposition to the protocole participation Outpatients group : \- Patient schedulded to undergo outpatient THA Inpatients group : \- Patient schedulded to undergo inpatient THA because of not fiting the following items : * Less than an hour distance of a Health Center that provides appropriate care with regard to the surgery * Rapid access to a phone * Designated driver and caretaker available (at least the first night after discharge from the hospital) after the procedure Or turning down outpatient THA Exclusion Criteria: * Anaesthetic point of view : * ASA physical status ≥ 3 and : unstabilize disease with appropriate treatment or lack of preoperative mutual agreement between anesthesiologist and surgeon or not inconsiderable interaction between the operation and the disease or its treatment * Pre-operative Hb \< 12 (♀) \< 13 (♂) g/L (NB : no Hb control before discharge except if excessive blood loss ; Hb \< 10g/L contraindicates outpatient surgery) * Opioid chronic pre-operative therapy or opioid addiction * Surgical point of view : * Ambulatory pre-operative status requiring use of two crutches or walking frame / distance walked \< 30 m * THA procedure for femoral neck fracture requiring * Additional operative technic needed * Adult safeguarding. Exclusion criteria applies to all in and outpatients.