Digital Study On Osteotomy Of Osteonecrosis Of Femoral Head And Reconstruction Of Acetabulum Defect Of Type ?B

BackgroundFemoral head necrosis has a high disability rate,and the patient are becoming younger and younger.The protection of heads in the middle and late stages of necrosis and the reconstruction after joint replacement are the difficult and hot spot of current research.Optimize head protection and acetabular reconstruction programs by digital medical technology are of great significance for good outcome of the disease.ObjectiveThrough the digital research on the reconstruction of acetabulum defect with rotation osteotomy and ?B,we hope to provide a new idea for personalized accurate treatment and device innovation of osteonecrosis and acetabulum side reconstruction.We studied rotational osteotomy and ?B type acetabular defect revision and reconstruction by digital research,in order to provide new ideas for personalized precise treatment and device innovation of the osteonecrosis and acetabular reconstruction.Methods1.We constructed 11 groups of osteonecrosis finite element models,and comprehensively evaluated different osteotomy schemes from the trend of necrotic expansion,the pressure of necrotic blood supply,and the risk of femoral head fracture collapse under the four daily activities.2.Using forward and reverse engineering software and three-dimensional printing system,we designed and rapid prototyped a rotational osteotomy guide plate,and innovatively used deviation analysis technology to evaluate the guide plate efficiency by comparing the position deviation of necrosis area,osteotomy surface and contour between guide plate group.3.Taking the TC4 8-hole reconstruction plate as an example,to explore the clinical applicability of metal printing,we compared and analyzed the bending,torsional,dynamic and static mechanical characteristics of the 3D printing and traditional groups,as well as the differences in hardness,composition,and roughness.4.We used pre-and post-processing simulation softwares to optimize the stiffness and minimize the micro-motion of the prosthesis-bone interface.And finally,we determined the best nail channel combination from 4004 combinations,and then optimized the reconstruction prosthesis structure accordingly.Results1.The risk of fracture increases gradually during standing on feet,normal walking and walking upstairs and downstairs.The correlation analysis shows it has a strong negative correlation(R2=0.834)with the average modulus of the roof.The comprehensive evaluation observed that rotating forward 90°could reduce the total risks to 64%.2.All the deviation indexes(except the position deviation of the third section)in the guide group were lower than those in the traditional group(P<0.05).3.The static bending and torsion properties of implants in 3D printing group were significantly higher than those in traditional group(P<0.05).The two kinds of plates suffered 106 cycles of load below 0.9KN,and the fatigue cycle of traditional plate is longer under larger load.4.After optimization,the volume of prosthesis was reduced by 38.96%,the surface area was reduced by 51.00%,the stiffness of prosthesis was slightly smaller than that of original prosthesis,and the micro-motion of the prosthesis-bone interface was less than 50 ?m.Conclusions1.The intertrochanteric rotation osteotomy can effectively reconstruct the mechanical environment of the weight-bearing area of the femoral head.For the C-grade necrosis of the anterior superior area,it is recommended to rotate 60°?90°forward or 180° backward.The improvement of the mechanical environment was related to the anterior or posterior bone modulus.2.The newly designed 3D printing guide plate can assist the precise implementation of intertrochanteric rotational osteotomy.3.The mechanical properties of direct metal laser sintering implants are better than those of traditional implants in bending and torsion,and the fatigue property is relatively poor,but it also satisfies the needs of clinical application under physiological load.4.The use of pre-and post-processing finite element software for multi-operation intelligent cycle optimization,topology and bead structure optimization could effectively assist in the optimal design of triflangeacetabular prostheses.Using this method to design a prosthesis can reduce structural stiffness,avoid stress shielding,while ensure that the micro-motion value of the prosthesis-bone interface is in the safe micro-motion range that is conducive to osseointegration.At the same time,it not only greatly reduces the volume and consumables of the prosthesis,abates the tissue irritation,but also makes it easier to implantation.And the host bone could be maximum retention.