Comparative Study Of Two Tibia Component Rotation Alignment Methods In Primary Total Knee Arthroplasty

Objective:Compare the short-term clinical outcomes and radiological results between range of motion technique(ROM)and tibial tubercle landmark technique(TTL)in tibia component rotation alignment.Analyze and evaluate the two rotational aligned methods.Methods:Sixty patients(60 knees)who underwent primary total knee arthroplasty from December 2018 to May 2019 in the Second Affiliated Hospital of Shanxi Medical University were retrospectively selected.Among them,30 cases underwent ROM technique and other 30 cases experienced TTL technique.In ROM group,there were 10 males and 20 females,with an average age of 66.4±6.1,and body mass index of 25.0±3.4.In TTL group,11 males and 19 females were included,with an average age of 65.0±4.3,and body mass index of 23.7±3.3.Collected the Hospital for Special Surgery Knee Score(HSS),Feller's patella score,Visual Analogue Scale score(VAS),and knee flexion and extension activity 3 months and 6 months after operation to compare the clinical effects.Contrasted the Hip-knee-ankle angle(HKA),mechanical lateral distal femoral angle(mLDFA),mechanical medial proximal tibial angle(mMPTA)and posterior slope angle(PSA)through measuring the X-ray.And the comparation of tibia component rotation angle relative to surgical transepicondylar axis(sTEA),Akagi line and tibia posterior condylar line(PCL)by the postoperative knee computed tomography(CT).Results:No statistical difference existed in preoperative general data,clinical score and radiological results between two groups(P >0.05).The HSS score,Feller's patella score,VAS score and knee flexion and extension activity were improved significantly after TKA in both groups.The HSS score,Feller's patella score and VAS score at three and six months after surgery were better in TTL group than ROM group,the difference was statistically significant(P<0.05).Knee flexion and extension activity had no statistical difference(P>0.05).In terms of radiological results,the postoperative HKA,mLDFA,mMPTA and PSA had no statistically significant difference.In ROM group,the angle between tibia component axis(TCA)and sTEA,Akagi line,PCL were 1.86±4.5°,2.33±4.3°,0.72±4.8°.In TTL group,the angle between tibia component axis(TCA)and other three reference lines were 3.51±3.1°,4.41±3.2°,1.6±3.5°.Positive value represents external rotation.The angle relative to Akagi line in two groups had a statistically significant difference(P <0.05).Conclusion:It was found that both methods could obtain a good outcomes through the evaluation of postoperative clinical effects and radiological results.Moreover,compared with ROM group,TTL group had larger external rotation angle of tibia prosthesis,smaller dispersion degree and better clinical scores.But due to the deformity and variability of tibial tubercle,referring to the tibial tubercle blindly sometimes leads to malrotation.The surgeon should also master ROM technique,according to the specific situation to choose the appropriate rotation alignment method during the surgery,or two methods used at the same time,so as to reduce the incidence of tibia component malrotation.