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)