Patient-Specific Techniques for Hip Replacement

Kinematic vs Mechanical Alignment Technique for Primary Total Hip Replacement in Patient With Hip Arthritis: a Prospective Comparative Non Randomised Study

Background In the 19th century, Sir John Charnley successfully introduced total joint replacements for hips. In order to prevent implant fixation failure and accelerated polyethylene wear, it was initially recommended that implants were systematically positioned in a "biomechanically-friendly" way, which disregarded most of the individual anatomy (medialized acetabular cup, systematized cup version and inclination, etc.) While those initial surgical techniques made popular and clinically successful total joint replacements, many complications (aseptic loosening, pain, excessive wear) have remained and mainly the persistence of frequent instability after THA. In response to those complications, many improvements were developed in the area of joint replacement over the last few decades, with one the most recent dating from 2017 and being the development of a surgical technique Rationale The kinematic alignment (KA) technique for total hip arthroplasty (THA) aims at restoring the acetabular center of rotation and as much as possible the constitutional acetabular anteversion by using the transverse acetabular ligament (TAL) as a reference landmark. Also, the technique aims (1) at making personalized choice for the hip component design, (2) at defining the cup positioning, and (3) at sometimes considering additional spine surgery based on the assessment of the individual spine-hip relation. KA techniques for hip replacements are relatively new, likely to become popular over time, and their true value remains to be determined.

Objective: Evaluation of the kinematic alignment technique for hip prostheses in patient with hip osteoarthritis Hypothesis: the consideration of hip pathoanatomy and lumbo-pelvic kinematic disorder when planning a hip replacement is likely to decrease the risk of prosthetic dislocation and improve patient function and satisfaction

Osteoarthritic patient undergoing the conventional technique medializing the hip center of rotation obtain a standing acetabular cup position fitting the Lewinneck recommendations (inclination 40°±10°, version 15°±10°)

Osteoarthritic patient undergoing the kinematically aligned technique restoring the acetabular center of rotation restoring the constitutional acetabular anteversion by using the transverse acetabular ligament (TAL) as a reference landmark. making personalized choice for the hip component design considering additional spine surgery based on the assessment of the individual spine-hip relation.

Implant positioning parameters (inclination, version, offset) are computed on post-operative X rays acquisition.

Inclusion Criteria: Osteoarthritic hip patients eligible for primary total hip arthroplasty (THR). > 18 years-old with no upper age limit Affiliated to a social security scheme Exclusion Criteria: Pregnant or lactating women or in age to procreate without contraceptive treatment History of mental illness or neurological deficit or adults lacking capacity to consent for themselves Prisoners or young offenders Persons who might not adequately understand verbal explanations or written information given in French, or who have special communication needs Subjects having been or being frequently x-ray examination Heart failure with risk of exercise angina or comorbidity(ies) significantly affecting patient function Any participants who are involved in current research or have recently been involved in any research prior to recruitment.