Is the Dynamic of the Pelvic Bone Altered After a Total Hip Replacement ?
Is the Dynamic of the Pelvic Bone Altered After a Total Hip Replacement ?
Total hip replacement is one of the most common surgical procedure in France. In 2010, an
 estimated 147 513 total hip procedures were performed. This number is constantly increasing.

 Although it is common, it can lead to many complications. The intra-prosthetic luxation is
 the second one after aseptic loosening.

 The luxation risk is multifactorial and depends on the relative orientation of femoral et
 acetabular components. This orientation is influenced by statics and dynamics parameters.

 So far, the literature shows that only static parameters are considered by surgeons. Thus, in
 reference to Lewinneck publication, which states that the luxation risk is lower if the cup
 is oriented with 15° +/- 10° of anteversion and 40°+/- 10° of inclination with respect to the
 anterior pelvic plan (APP). Defined by the two anterosuperior iliacs spines and pubic
 symphysis.

 However, this approach is only static and do not take into account the variations of pelvic
 plan orientation during everyday life.

 To consider these variations of pelvic inclination, it is possible to measure the angle
 between APP and the horizontal (in lying position) or the vertical (in standing position)
 plan.

 Several devices allow the measure of pelvic inclination but they all have important limits
 (EOS radiography, scanner or navigation). A new device has been developed in Brest to measure
 this inclination in several positions of the daily life.This software has already been tested
 in healthy volunteers and results demonstrate an excellent accuracy and reproducibility.

 The goal of this study is to described the dynamic of the pelvic bone thanks to this
 ultrasound based device, and to assess the amount of variation induced by hip replacement
 procedures.
Inclusion criteria :

 -  Patient with primary or secondary hip arthritis, at stage II to III of the
 radiological classification of Tönnis and for whom total hip replacement is indicated
 by surgeon.

 -  Signed consent

 -  Patient beneficiary of a social security plan

 Exclusion Criteria:

 -  Patient Under 18

 -  Patient Under protective measure (guardianship, curatorship) or unable to consent

 -  Patient requiring revision THR

 -  Patient with geographic mobility plan before the end of the follow-up

 -  Symptomatic contralateral hip

 -  Symptomatic dorsolumbar rachis

 -  Pelvis or spine surgery planed during the follow-up

 -  Pregnant or nursing woman