The Femoral Coronal Bowing's Influence On The Measurement Of The Lower Extremity's Alignment And Its Individual Difference Influence On Total Knee Arthroplasty

Part ? Analyse the different revolving postures' influence on the measurement of femoral coronal bowing's and femoral vulgas correction angle by CT three-dimensional reestablished model.Object:The aim of this study was to evaluate the influence of rotary posture on the metrical resultes of the femoral bowing angle(FBA)and the femoral vulgas correction angle(VCA)through the lower limbs skeleton model which reestablished from the CT scaned data.Methods:Choose the qualified cases from the vascular surgical patients of our hospital who had been examined by lower limbs angiography Computed Tomography.Rebuilt the lower limbs bones'model by mimmcs 16.0 software.Separate the cases into four groups by their femoral bowing angle(FBA)in the standard a-p position,such as group A(FBA>2),group B(2>FBA>0),group C(0>FBA>-2)and group D(FBA<-2).There are 5 cases in every groups.Then make every model revolved through the vertical axis from 20 degree internal rotation to 20 degree external rotation by 2 degree for one motion and then get 21 photography for every case.Measured every photography's FBA and femoral vulgas correction angle(VCA).Results and Conclusion:?The measured FBA values of the 4 groups cases were 2.49°±0.46°(group A),1.06°±0.39°(group B),-1.41°±0.49°(group C),-3.49°±0.74°(group D).? The limb's external rotation increase the FBA,the limb's internal rotation decrease the FBA and the bigger FBA's value in standard a-p position,the sharper variation of measured FBA value.The regression coefficient of each group is 0.47°/°(groupA),0.34°/°(groupB),0.33°/°(groupC)and 0.35°/°(groupD).?The regression coefficient between the measured VCA value and limb's rotation in the 4 groups respectively are0.1°/°(groupA),0.03°/°(groupB),0.04°/°(groupC)and 0.070/0(groupD).?The correlation index of the FBA and VCA in the different positions are 0.86(GroupA),0.80(GroupB),0.88(GroupC)and 0.85(GroupD).?The FBA value can be altered with the limbs' rotation and even produce influence on the measurement of the whole limb's alignment.And the bigger FBA's degree,the more influence on the alignment.So when make the full length X-ray of lower limbs,making a standard posture for the legs is the key point,especially when a femur with a hyper-femoral bowing.Part ? The individual difference of coronal bowing of femur and its influence on the lower limbs alignment and the total knee arthroplasty.Objective Measure the femur bowing angle(FB A),vulgas correction angle(VCA)and other parameters from the whole leg X-ray of the patienes who had sought for the total knee arthroplasty(TKA)treatment in our department and then analysye the data.Try to disclose the correlation between the FBA and VCA,anlysys its influence on the total knee arthroplasty and the lower limbs alignment.Methods Collected the eligible cases who had seek for TKA in the department of Joint Surgery,China-Japan Friendship from Janurary in 2013 to December in 2015.Measure the FB A,VCA,offset of the proximal femur,the lengh of the femur,the neck shaft angle and the lateral distal femural angle(LDFA)of the femur of the eligible cases from the long leg X-ray.All the data were analysed for the following steps:?The FBA's mean value and characteristics of distributation of all the cases.?The VCA's mean value and characteristics of distributation of all the cases.?Correlations between the VCA and the other parameters;?Divide all the cases into four regions base on the value of FBA:region A(FBA<-3°),region B(-3°?FBA?0°),region C(0°<FBA?3°),region D(FBA>3°)and then imitate cuting the distal femur with 5° and 6°,respectively.Compare the percent of ideal alignmental outcome of every region.?Divide all the cases into three groups base on the valgus osteotomy method:The first group which osteotomy by the 5 degree-valgus,the second group which osteotomy by the 6 degree-valgus and the third group which valgus osteotomy based on the actual VCA.Compare the percent of ideal alignmental outcome's of every group on each FBA's region after the TKA.Results:?The mean Value of the FBA is 1.37°±2.42°(-7.06°-12.12°),?The mean Value of the VCA is 6.51°±1.34°(2.47°-11.91°);?The correlation index between VCA and FBA,the neck shaft angle of the femur,offset of the hip joint,the lengh of the femur is 0.72,-0.26,0.45 and-0.08,perspectively.?The theoretical ideal alignment percentage Of the 5 degree-valgus-bone cut and 6 degree-valgus-bone cut in every group is region A:89.66%and66.52%;region B:93.73%and 95.69%;region C:71.88%and 94.58%;region D:21.19%and 50.80%,respectively.?The's percent of ideal alignmental outcomes in region A are 76.92%(the first group),56.56%(the second group),85.71%(the third group),respectively.In region B the results are 91.90%(the first group),93.75%(the second group),92.64%(the third group),respectively.In region C the results are 86.49%(the first group),92.02%(the second group),96.64%(the third group)and the results are 33.64%(the first group),61.29%(the second group),84.72%(the third group)in region D.Conclusion The cases whose femur bowing angles are outliers are common in daily medical practice,so the vulgas correction angles need be ajusted for its significant correlation with FBA.5 degree-valgus-bone cut or 6 degree-valgus-bone cut could not get the ideal alignment always.