Total Hip Arthroplasty Instability and Lumbo-pelvic Kinematics: EOS Imaging Assessment of Variation in Spinal and Pelvic Parameters From Standing to Sitting

Inclusion Criteria: * The patient must have given their free and informed consent and signed the consent form * The patient must be a member or beneficiary of a health insurance plan * The patient must be at least 18 years old and less than 85 years old * Patient has a conventional first intention total hip arthroplasty (not dual mobility) by posterior approach * "Case" patients have at least one previous episode of prosthetic dislocation repaired with surgery * "Control" patients have no previous episode of prosthetic dislocation with more than 2 year since initial intervention Exclusion Criteria: * The subject is participating in a category 1 interventional study, or is in a period of exclusion determined by a previous study * The subject refuses to sign the consent * It is impossible to give the subject informed information * The patient is under safeguard of justice or state guardianship * Patient is pregnant, parturient or breastfeeding * Patient with lumbar instrumentation * Patient with severe dementia (Mini Mental State Examination \< 10) * Patient with American Society of Anesthesiologists score ≥ 4 * Patient experience multiple falls * Patient requiring early revision surgery (\<15 days postoperatively * Patient with obvious implant positioning error on an X-ray of the pelvis. * Patient with dislocation of traumatic origin (significant kinetic trauma)