Effect Of Total Knee Arthroplasty On The Alignment And Pain Of Ankle Joint

Objective:To explore the changes of the ankle joint alignment after total knee arthroplasty(TKA);and analyze the effect of the changes on the pain of the ankle joint after TKA for knee varus with ankle osteoarthritis(OA).Methods: From April 2018 to December 2019,a total of 85 patients(90knees)who were continuously underwent primary TKA with knee varus OA and followed up more than 6 months were collected.Datas were collected from weight-bearing whole leg anteroposterior radiographs of lower limbs before operation and during postoperative follow-up.Then,1.Hip-Knee-Ankle angle(HKA),Hip-Ankle line and Tibia angle(HAT),Medial Proximal Tibial Angle(MPTA),Tibia Anterior Surface angle(TAS),Tibial Talar Surface angle(TTS),Talar Tilt angle(TT),angle between the Ground and the upper Surface of talus(GS),tibiotalar joint space(LA),distal medial clear space(LB)before and after TKA were compared;2.Analyze the correlation between GS,TT and HKA as well as the correlation between the change of GS,TT and HKA(ΔGS,ΔTT and ΔHKA);3.The difference of the incidence and Visual Analogue Scale(VAS)of ankle pain in patients with knee varus OA group before and after TKA were compared;According to the preoperative ankle joint condition,they were divided into the with ankle OA group and the without ankle OA group.The difference of incidence of ankle joint pain,VAS of the ankle joint and related radiological parameters before and after TKA were compared between two groups.Results:1.GS after TKA was 4.3°±3.6°,which was less than the preoperative9.5°±4.9°,GS decreased by an average of 5.2°,the difference was statistically significant(t=13.142,P<0.001);TT after TKA was 0.5 °±1.6°,less than the preoperative 1.0°(0.1°,2.2°),TT decreased by 0.6° on average,the difference was statistically significant(Z=-2.944,P=0.003);LA after TKA was 2.9mm(2.6mm,3.1mm),greater than the preoperative 2.8mm(2.5mm,3mm),the difference was statistically significant(Z=-3.020,P=0.003).2.For knee varus OA before TKA,GS was positively correlated with HKA(correlation coefficient r=0.581,P<0.001),TT was not correlated with HKA(P>0.05);while GS and TT were not correlated with HKA(P>0.05)after TKA;For the change before and after TKA,ΔGS and ΔHKA are positively correlated(correlation coefficient r=0.552,P<0.001);ΔTT is not correlated with ΔHKA(P>0.05).3.The VAS score in the with ankle OA group was 0.76±1.48 preoperative and 1.41±1.77 postoperative,the difference was statistically significant(Z=-2.070,P=0.038);The VAS score of the ankle joint in the without ankle OA group was 0.27±0.69 preoperative,and 0.23±0.64 postoperative.The difference was not statistically significant(Z=-0.242,P=0.809).There was no significant difference in the incidence of ankle joint pain between the two groups before and after TKA(P>0.05).There was no statistical difference in gender,age,BMI,affected side and follow-up time between the two groups(P>0.05).Conclusions:1.For those knee varus OA without ankle OA preoperative,there is no significant change in the pain of ankle joint after TKA;However,for those with ankle OA preoperative will have more ankle pain after TKA.It is necessary to carry out the corresponding preoperative examination and postoperative management of the ankle joint undergoing TKA.2.For knee varus OA,TKA has no significant effect in the incidence of ankle joint pain.3.For knee varus OA,ankle varus angle is positively correlated with knee varus angle;The talus tilt decreased and the ankle joint distance increased after TKA.Ankle varus compensation is positively correlated with knee varus correction after TKA.