Application Design And Experimental Study Of Digital Navigation Templates In Hip Replacement Acetabular Positioning

ObjectiveThrough computer-aided (Computer Aided Design, CAD), the use of three-dimensional reconstruction Mimics(3-D Reconstruction) software,Geomagic studi oll.0reverse engineering software, combined with rapid prototyping technology (Rapid Prototyping,RP) and three-dimensional drawing software Solidworks desi gn and production of a new types of digital, precise, individualized, practical a cetabular navigation template for total hip arthroplasty(Total Hip Arthroplasty,T HA) accurate implantation of the acetabular component provides a simple and effective new methods and aids to ensure hip arthroplasty acetabular prosthesis as possible to return to the anatomical position.Method1.An acetabular center of rotation normally determined:normal pelvic com plete bodies of CT pelvis continuous scan scanning range containing the examp le includes bilateral hip joint,up to the anterior superior iliac spine,the proximal end to the femoral shaft.Scanning parameters:thickness of0.630mm, the voltag e120KV, current150MA, the matrix is512x512, a scan time is about15-20s. The CT scan data saved as DICOM format,the acquired data into three-dimensi onal medical image reconstruction software Mimics10.01,through manual or aut omatic threshold segmentation and reconstruction after editing the complete stru cture of the pelvis and hip, pelvis and femoral head according to different thre shold range,the three-dimensional model of the pelvis separately extracted,saved as STL format.Then import Geomagic studio11.0and Mimics10.01software f or analysis and processing.Extraction side of the moon-shaped face acetabular s urface point cloud data,the best fit sphere,whose center of the sphere is normal acetabular center of rotation, and get the properties of the sphere radius.2.Ipsilateral acetabular hip rotation center and azimuth determined; preopera tive pelvic CT scans continuously tomography,CT scan data will be saved as D ICOM format,import medical image reconstruction software Mimics10.01,throug h manual or automatic threshold segmentation and after editing a complete thre e-dimensional reconstruction of the pelvis and hip structure, according to the p elvic and femoral different threshold range, the three-dimensional model of the separation of the pelvis extracted, saved as STL format.Then import Geomagic studio11.0software for analysis and processing. Side will be studied as a tern plate to define the side contralateral control side is defined as.And assuming th e template side of the lesion side,as the contralateral control side.(1) extracting contralateral acetabular lunate surface of the point cloud data,the best fit spher e,whose center of the sphere is the center of rotation of the acetabulum,import Mimics10.01software,determine the pelvis mirror plane,the use of a mirror pri nciple,determine the center of rotation of the ipsilateral acetabular;(2) in Mimic s software,preoperative CT coronal plane and in a horizontal plane to measure the acetabular abduction and anteversion angle β α.Establish a coordinate syste m,the origin of the ball center is set to calculate the rotational axis of the acet abulum,the acetabular axis;(3)To reconstruct a three-dimensional model of the p elvis in a good format to import STL Geomagic studio11.0software to acetab ular fossa ovalis template fields to extract its anti-mold technology to build u sing reverse acetabular anatomy and conform to the shape of the surface of th e oval fossa reverse template by law to generate the virtual2mm thick oval fo ssa acetabular anti-mold.Combination with the axis of the acetabular surface o f the acetabulum as a whole generated;(4)Three-dimensional drawing software a pplication designed Solidworks acetabular Kirschner wire guide axis and the ad justable rod template file acetabular socket,and304stainless steel create entitie 3.Digital navigation templates applied and experimental research on cadave rs,take10cadavers with a complete pelvis,excluding pelvic fractures,deformities, tumors,stunted growth and other factors.Dissected corpses supplied by the Kun ming Medical University.Preoperative anteroposterior pelvic X-ray and CT scan, scan range,including the hip,the anterior superior iliac spine up and down to th e proximal femoral shaft. Scanning parameters:thickness of0.630mm, the vol tage120KV,current150MA, the matrix is512×512,a scan time is about15-20s. Depending on the patient’s CT data with mimics10.01and Geomagic studio11.0software designed acetabular digital navigation templates,STL format to hip a cetabular fossa ovalis virtual navigation template input laser rapid prototyping machine to a photosensitive polymer resin as raw material,using light curing te chnology to generate navigation template entities.Side will be studied as a tem plate to define the side contralateral control side is defined as. And assuming the template side of the lesion side,as the contralateral control side.Test by po sitioning the acetabular side template navigation template to determine the aceta bular prosthesis placement and acetabular acetabular implant tryoutPostoperative pelvic X-ray films,CT scans and other tests,abduction angle after comparing t he experimental side and the control side,anteversion,the center of rotation to t he vertical distance and horizontal teardrop distance.Using statistical software S PSS13.0for statistical analysis and processing and evaluation.ResultAfter the end of the experiment, Using X-ray (anteroposterior pelvis film) and CT scans to measure the experimental side (template side) after the abduct ion angle,anteversion.Vertical and horizontal distance from the center of rotation perpendicular to the teardrop distance and camparing with control side. The fr ont side of the acetabular template;template side acetabular abduction angle was46.57°±2.87°, the control side was47.14°±2.67°:measurements using SPSS13.0software for statistical processing and analysis, paired T-test line,the results sh ow inclination of16.44°±1.47°, the control side was15.86°±1.88°;template sid e HJC horizontal distance was36.89°±2.16°, the control side was36.87°±1.5°;v ertical distance from the template side HJC was27.25°±3.08°,control side was26.48°±2.11°.Before and after the experiment acetabular abduction angle (β) by paired T-test,t=0.936,P=0.373,namely,P>0.05; acetabular anteversion after the ex periment (a) by paired t test,t=1.292,P=0.229, namely,P>0.05;around experiment al HJC horizontal distance (W) by paired t test,t=0.39,P=0.970,namely,P>0.05;b efore and after the experiment HJC vertical distance (H) by paired t test,t=1.076,P=0.310,namely,P>0.05.Statistical analysis showed that the experimental side o f the front and rear template acetabular abduction angle (β),acetabular anteversi on (a),HJC horizontal distance (W),HJC vertical distance (H) compared with th e control side,P values were greater than0.05,the difference was not statisticall y significant,that there was no significant difference between the experimental s ide and the control side templates around.Conclusion1.Application Mimics software and three-dimensional reconstruction Geomagic Studio reverse engineering software, through the acetabular lunate surface fitting best ball and accurately calculate the HJC,namely, the position of the acetabulum; accurately calculate the azimuth of the concept through the acetabular acetabular rotation axis,and the direction of the acetabulum.While meeting the acetabular position and orientation of these two conditions before they reach the ideal acetabular prosthesis.2.Depending on the individual acetabular fossa ovalis,the use of reverse en gineering technology to build individualized reverse template,to ensure a good match between the template and the oval fossa,but also has a good guide.3.The subject of the use of Solidworks software design a simple and flexi ble Kirschner guide rod sleeve acetabular file,reusable,economical and practical good.Combined with Mimics software,Geomagic Studio software,rapid prototypin g technology for acetabular polished,accurate acetabular cup implant provides a feasible and effective new methods.Avoid the naked eye doctors and clinical e xperience alone positioning of subjectivity.