The Three-dimensional Finite Element Analysis Of Un-cement And Cement Femoral Prosthesis Implanted Under Different Bone Density

[Background] With the rapid development of the material science andmedical science, the life quality, the medical treatment health care and recoverfrom illness have been raised increasingly. In recent years, the artificial jointdisplacement surgical operation is the valid treatment method has gainedextensive application in the clinic. But there are a lot of factors affect thedisplacement result. For example: different appearances and quantity of the boneshape, surgical operation technique, and the bone cavity shape. These factorsinfluence the judgment of the replacement. Individual bone density distribution,age sex can't attain completely the same. Moreover, It is already known that theprosthesis-bone interface quantity and unity is also the relevant problem. Besides,it is possible for us to select each patient to do a biomechanics experiment in-vitro.Three dimensional finite element analysis of bone is available. The biomechanics,and ability of experiment condition carried on control to bone with emulationunder of mechanics circumstance to the patients are invasive and is without injury.[Objective] In the present study, we Make use of the Solidworks software toreconstructed the femur and prosthesis 3-D model. And evaluated the bonedensity in different individual, therefore to find a new way to chose the differenttype of femoral prosthesis to the patients. We separated the patient into differentgroups according to their age, and there are altogether 32 groups. The study willgive us a better understanding to the load transmition along the models. Thereforeit will be easy for us to see which model has a better distribution of the load andchose the best one under different bone density. Through this study we have laid abiomechanical foundation to the clinical doctor on how to chose the different typeof the femoral prosthesis according to the different bone density. [Material and method] 1. The three-dimensional reconstruction of the femoral prosthesis 1.1 The obtain of the CT images GEspeedlight 16CT scanned one fresh adult cadaver femoral from theproximal to distal part. There was 1.25mm between each scanned slice and thetwo-dimensional images of each slice were obtained. All the obtained data wereput into the computer workstation for the later use. 1.2 The process of the obtained CT images The two-dimensional images of each slice in the workstation were conversedinto the compact disc files and recorded on 700M CD-R. Through the calculation,we directly gained the CT images and using own developed CAD software carriedon later experiments. 1.3 The edge detective Use Canny edge detective system to detect the images'edges. 1.4 The conversion of two-dimensional images to three-dimensional one The originally obtained two-dimensional data were transformed intothree-dimensional picture in order to make the picture more real for observation. 2. The three-dimensional reconstruction of cement and biological femoralprostheses 2.1 The CLY single-arm three-dimensional measurement device (made inChina measurement technical institution) was used in measuring the cement andbiological femoral prostheses. All measure data were put into the same coordinate. 2.2 The three-dimensional reconstruction of cement and biological femoralprostheses model was automatically performed through the Solidworks 2001. 3. The simulate comparison biomechanical experiment of cement ,biological prosthesis according to the different bone density. 3.1 The simulation finite analysis of these prostheses. 3.2 The simulate comparison biomechanical experiment of cement,biological prosthesis according to the different bone density. In the computer theTHA surgery were simulated and the load distribution,interface-load,micromotion around the prostheses were measured under the one-foot stand condition. [Result] The present study proves: with the bone density decrease, the loaddistribution will increase. The largest load distribution is around the distal part ofthe prosthesis. the statistical analysis results show: whatever the male and femaleunder the one-foot standing condition, in biological prosthesis, the Mises load,and press load are all enhanced in the distal part of the femoral. With the changein the bone density, the best load distribution appears in the male age 30-40 theaccordingly bone density is 0.851±0.064g/cm2; and the best load distributionappears in the age 30-40 female accordingly bone density is 0.766±0.08g/cm2. Inthis bone density range, it also has the most minimal micro motion and press load.In the cement femoral prosthesis, at the age range in male 60-70 accordingly bonedensity is 0.7143±0.063g/cm2.and the female age 50 accordingly bone density is0.6963±0.08g/cm2 have the best and unit load distribution. [Conclusion] This experiment enunciation: 1) Whatever the gender is under the one-foot standing condition, the largestdistribution of the Mises load is focused around the distal part of the femur.