The Measurements And Analyses Of Full-length Weight-bearing X-ray Radiographs Of Bilateral Lower Extremities In Knee Osteoarthritis Cases

Objective To analyze the characteristics of anatomical and mechanical axes in lower extremities by applyingfull-length weight-bearing X-ray radiographsin patients with knee osteoarthritis.Methods From September 2015 to May 2016,the lower extremity CTA were taken from 20 patients with Vascular diseases,as the normal group.There were 7 males and 13 females,ranging in age from 24 to72 years,with an average age of 63.2 years.The weight-bearing full-length X-ray radiographs of the lower extremities were taken from 53 patients with knee osteoarthritis,as the osteoarthritis group.There were 10 males and 43 females,and age ranged from 52 to 80 years,with an average age of 64.7 years.And the osteoarthritis group were divided into two groups:varus knee group and valgus knee group.The femoral shaft double condyle angle(F),tibial shaft plateau angle(T),joint gap angle(JS),femoral tibial angle(FT),hip-knee-ankle angle(HKA),knee physiological valgus angle(KPV),and femoral offset were measured.The SPSS 21.0was applied for the Statistical data analysis.Results In the two groups,the mean F were 79.9±2.3°and 81.4±3.5°,T were 93.8±3.7°and 94.6±2.7°,JS were 1.7±1.0°and2.1±2.5°,FT were 175.4±4.0°and 178.1±6.3°,HKA were 181.4±4.1°and 184.5±6.7°,KPV were 6.0±1.0°and 6.2°±1.5°,offset were 38.5±6.5mm and 38.1±9.2mm.There was a significantly difference in the KPV between varus knee and valgus knee groups(t=2.956,P=0.005),while greater mean KPV was found in varus knee.Positive correlations were found between KPV and age(r=0.241,p=0.016),as well as between KPV and offset(r=0.946,p=0.000).Conclusion The average KPV in knee osteoarthritis cases was 6.2°in the current study,and the KPV was also positively correlated with the patients' age and the femoral offset.The average KPV in the varus knee was greater than that of the valgus knee,and the difference was about 1°.The changes of mechanical parameters of lower limb may be one of the reasons for the development of knee osteoarthritis.Analyzing the full-length weight-bearing X-ray radiographs of the lower extremities preoperatively will further contribute to individualized osteotomy for total knee arthroplasty.