| Objective:This experiment through establishing CAD model to locate acetabulumcenter and the nomal adult corpses speciments to systematically observe the anatomicfeature and relative of fossa ovalis and acetabular center and acetabular notch, toexplore the problem that how to make sure acetabular center and hip center of rotationin the operation of total hip arthroplasty, especially in the dysmorphism acetabularand the revision after THA. So we can provide reliable basis of anatomy forimplanting acetabulum cup in the THA and the revision after THA.Methods:The experiment choose16normal adult corrosion specimens, male as femalwere same8cases. According to the Boyd style, we Layered cut skin andsubcutaneous tissue,so as to explore the hip joint completely， and peel the softtissue around the acetabulum,(unabridgedly retained the acetabular horizontalligament, it willed be removed after finding the HCR) and find the fossa ovails byround ligament,keeping the construction of cartilage and bone of acetabulum andobserving the he acetabular is complete and any abnormalities.Using reverseengineering, we can obtain the point cloud forms through scanning the acetabulumand fit a best sphere that use the point cloud forms image, The center of sphere isHCR or O’ point.The so-called reverse engineering, that is the existence of thephysical model or part be measured, according to real measured data reconstructedcomputer aided design (computer aided design CAD) model and real objects byprocessing a complex process of reconstruction The model can fully reflect thegeometric features of the original kind. We can located the center of sphere in thethree coordinates status. Then we make a plane at the opening of acetabulum that isbest fitting, through the HCR do a straight line that perpendicular to the plane with thefossa ovalis have a intersection, the intersection is AC or O point. We align the CAD model (Theoretical and practical products combined in the same location) andPositioning AC in the CAD model, so that automatically measuring the O pointthrough O’O by CMM In real specimens, the coordinate measuring machine scanningprobe contact with the acetabulum is the AC. Finding the point A and B that belocated in the acetabulum cut trace slit’s front and rear point.C point as the midpointof AB, then we do a line OD through O point that parallel horizontal plane when thepelvis is side position. Extension cords of CO and the edge of Harris fossa intersectat point E. To measure the distance of OA,OB,AB,OC,OE,∠COD. Appling SPSS17.0for statistical to observe relativity in them.Results:1. the distance about acetabular center point and acetabular cut trace slit’sfront and rear point, male OA:(32.25±0.94)mm，OB:(32.86±1.10)mm,female OA:(31.43±2.29)mm， OB:(32.15±1.73)mm. the distance about acetabular cut traceslit’sfront and rear point,male AB:(22.51±1.27)mm，female AB:(21.76±1.18)mm，thedistance about acetabular center point and C point of the midpoint AB, maleOC:(29.47±0.77)mm，female OC:(28.26±1.53)mm. the distance about extension cordsof CO and the edge of Harris fossa intersect,male OE:(8.35±1.00)mm,female OE(7.92±1.03). the angle with OC and OD, male∠C OD:(49.30±2.59)o， female∠C OD:(49.67±2.90)o.The experiment single factor analysis of variance with pairwisecomparison LSD (L) method P>0.05, men and women on both sides was notsignificant.2. In this experiment, we can draw a conclusion about male AB and OC isa positive correlation by linear correlation analysis (r=0.580,P=0.048). female B andOC is a positive correlation too (r=0.728,P=0.007).Conclusion:1. Acetabular center is located in the cephalic of fossa ovails which nearthe articular cartilage. The distance of acetabular center and thecephalic of fossa ovails, male OE:(8.35±1.00)mm,female OE (7.92±1.03).2The point of normal acetabular center and the two points of acetabularnotch form a isosceles triangle which its bottom is the connection ofacetabular notch. AC located the the vertical split line connection ofacetabular notch. male OA(32.25±0.94) OB:(32.86±1.10); female OA (31.43±2.29)mm OB:(32.15±1.73)mm; Male OC:(29.47±0.77)mm,female OC:(28.26±1.53)mm。3. The steady relativity of acetabular notch and Harris fossa acetabularcenter could offer anatomic basis of reconstructing HCR and fixingacetabular implant ideal in the THA or hip arthroplasty... |
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