Clinical And Radiographic Results Of Reconstruction Of Rotation Center In Revision Hip Arthroplasty

Objective To evaluate the clinical results of positioning the acetabular center,fixingacetabular implant correctly and reconstructing hip rotation center according toHarri-s fossa and the remaining anatomical markers of acetabular notch in revisionhip arthropl-asty.Methods From May2004to January2012,45cases(50hips) with acetabular bonedefects were performed acetabular reconstruction.33cases (35hips) were availablefor co-mplete clinical and radiographic analysis.There were16males and17femaleswith an av-erage age of57years(range34-79years),Among35hips,23hips involvedin left side a-nd12hips involved in right side.The average interval between theprimary total hip arthr-oplasty and the revision was10.2years (range,3-24years).Therevision causes included o-steolysis and aseptic loosening.30hips underwent revisionfor the first time,4hips for th-e second time and1hip for third time.According toPaprosky classification standard, ty-peⅠwas5hips, typeⅡa was5hips,typeⅡbwas8hips,typeⅡc was3hips,type Ⅲa was9hips,typeⅢb was5hips.The centerof the original acetabulum was believed to be in the lunate cartilage surface whichwas closed to Harris fossa．During the operation,the center was located in the sitewhich was25—28mm above in line with perpendicular bisector of acetabular notchconnecting line．The acetabular center was the point of posit-ioning acetabularprosthesis. Clinical and radiological evaluations were conducted for each patient. Thevertical distance from hip rotation center to teardrop connection and the hori-zontaldistance from hip rotation center to teardrop were measured on preoperative andp-ostoperative radiograph．And the outcomes of reconstruction of rotation center wereevaluat-ed. Results The mean follow-up period was4.4years (range,1to8years),The averageHarris hip scores improved from32.8points preoperatively to80.3points at finalfollow-u-p.The average Charnley hip scores improved from4.3points preoperativelyto14.6point-s.，The average myodynamia of gluteus medius improved from4.3gradepreoperatively t-o4.0grade.1hip occcurred postoperative dislocation afte2monthswith successful closed reduction.Aseptic loosening and migration were seen in3hips(2in acetabular and1in femoral),which needed re-revision (8.57%in failure).Heterotopic ossification developed in6hips (17.1%),4hips were rated as grade Ⅰ,1as grade Ⅲ,1as grade Ⅳ according to B-rooker classification.Conclusions Using residual Harris fossa and acetabular notch as the anatomicalmarkers in revision hip arthroplasty，the restoration of the anatomical hip cent-er hasshown to be favorable．...