Geometric Morphology Of The TKA Osteotomy Surface Of The Normal Mongolian Femoral Condyle

Objective:To study the geometry of the normal Mongolian population after osteotomy of the femoral condyle in the total knee arthroplasty(TKA)and the differences in the geometry of the femoral condyle with other ethnic groups.To improve the database of national knee geometry and to provide parameters for the design of knee prosthesis suitable for our Chinese population.Methods:Sixty-one(122 femoral condyles)Mongolian university student volunteers,21 males and 40 females,aged 20 to 25 years,were selected as the study subjects(hereafter referred to as the study group).There was no history of inter-ethnic marriage,no history of knee trauma,no history of knee disease or surgery,and normal knee development without deformity.In this study,122 knee joint data were obtained and 3D models of the knee joints were reconstructed using medical imaging techniques,computer techniques and other digital orthopedic techniques.The reconstructed model was applied to complete the osteotomy of the femoral condyle in accordance with the requirements and steps of TKA,and to measure each parameter after the osteotomy,as a way to analyze the geometric parameters and morphology of the knee joint of the national population in Inner Mongolia,represented by the study group.The CT images were saved in Dicom format and imported into a personal W520 computer,and Mimics 20.0 was used to reconstruct the 3D model of the knee joint,with the tibia and patella hidden,and the 3D model of the lower femur in Mcs format.save,import into 3-Matic12.0 software,perform simulation surgery,complete osteotomy of the femoral condyle in accordance with the TKA surgical requirements(i.e.,complete resection of the anterior condyle parallel to the anterior cortex of the femoral stem,osteotomy of the distal femoral condyle,posterior condyle,anterior bevel,and posterior bevel all with a thickness of 8mm,osteotomy of the distal femoral condyle with 6° of external rotation,and osteotomy of the anterior and posterior condyles parallel to the through-condylar axis)and steps to complete osteotomy of the femoral condyle,and measure and record the osteotomy The anterior-posterior diameter and the data of each osteotomy surface were measured and recorded.Nine brands of TKA prostheses commonly used in our hospital were collected,including five imported brands and four domestic brands,and the geometric parameters of the nine brands of femoral condylar trial molds were measured and recorded.The data results were statistically analyzed by applying spss 25.0 software,and independent sample t-test,correlation analysis,and ANOVA were performed to calculate the P value,and the difference was statistically significant when P < 0.05.Results:(1)By measuring the linear parameters of the osteotomy surfaces of the femoral condyles of the men and women in the study group and applying the independent sample t-test,the differences in the parameters of the osteotomy surfaces between the sexes were statistically significant(p < 0.05);the differences were not statistically significant(p > 0.05)when the linear parameters of the osteotomy surfaces of the femoral condyles of different sides of the same sex were subjected to the independent sample t-test.(2)Correlation analysis suggested that there was a correlation between the anterior and posterior diameters of the femoral condyle and the inner and outer diameters of the distal section(p < 0.05);there was a correlation between the width of the anterior femoral condyle section and the inner and outer diameters of the distal section(p <0.05);there was a correlation between the width of the anterior femoral condyle section and the inner and outer diameters of the distal section(p < 0.05).(3)The geometric morphological parameters of each osteotomy surface of the femoral condyle and the corresponding surface of the prosthesis in the study group,by independent sample t-test,the three groups of data,the inner and outer diameter of the distal femoral condyle,the cross-sectional width of the anterior femoral condyle oblique surface,and the width of the medial posterior femoral condyle surface,were not significantly different between the study measurement data and the corresponding data of the prosthesis(p > 0.05);for the remaining groups of parameters,the differences were statistically significant(p < 0.05).(4)The ratio of anterior-posterior femoral condyle diameter/distal femoral condyle inner and outer diameter for the study group and the nine manufacturers of femoral condyle prostheses was 0.799 for the mean of volunteers and 0.682 for the mean of prostheses,and the ratio of anterior-posterior femoral condyle diameter/distal femoral condyle inner and outer diameter for Mongolians was larger than the data for Europeans and Americans.Applying ANOVA,a significant difference of p < 0.05 was obtained.Conclusions:(1)There was a significant difference in the linear parameters corresponding to the femoral condyle osteotomy surfaces between the different genders in the study group.(2)There was no significant difference between the linear parameters of the femoral condyle osteotomy surfaces of the same sex and different sides in the study group.(3)In the study group,there was a linear relationship between the width of the anterior femoral condyle bevel section and the inner and outer diameter of the distal section;there was a linear relationship between the width of the anterior femoral condyle section and the inner and outer diameter of the distal section;there was a linear relationship between the anterior and posterior diameters of the femoral condyle and the inner and outer diameter of the distal section.(4)The geometric morphological parameters of each osteotomy surface of the femoral condyle and the corresponding surface of the prosthesis in the study group were significantly different,except for the three groups of distal femoral condyle internal and external diameters,anterior femoral condyle oblique cross-sectional width,and medial femoral posterior condyle surface width.(5)The ratio of anterior-posterior femoral condyle diameter/distal femoral condyle internal and external diameter in the study group was significantly different compared with the ratio of prosthesis dimensions provided by nine common knee prosthesis manufacturers used in our hospital.Therefore,gender differences should be taken into account in the design and manufacture of femoral condyle prostheses for the knee.Also,considering the reality of a large patient population,it is a very necessary and urgent task to design knee prostheses suitable for the national population,especially the Mongolian population in the northern region.