运动学对线与机械学对线对初次全膝关节置换术患者下肢对线参数的影响

Comparative study of lower-limb alignment imaging parameters between kinematic and mechanical alignment in patients with primary total knee replacement

目的探讨运动学对线(KA)-全膝关节置换术(TKA)与机械学对线(MA)-TKA手术前后下肢对线影像学参数的变化,分析术后残余内翻的原因。方法回顾性队列研究。纳入2020年6月—2021年1月首都医科大学附属北京朝阳医院骨科接受TKA患者36例,其中男17例、女19例,年龄58~82岁。TKA术中采用KA技术的18例纳入KA组、采用MA技术的18例纳入MA组。比较2组患者年龄、性别比例、体质量指数(BMI)、侧别以及手术时间等基线资料,对比分析两组患者手术前后髋膝踝角(HKA)、胫骨近端内侧角(MPTA)、机械股骨远端外侧角(mLDFA)的变化以及畸形矫正程度,并对每组患者手术前后的HKA、MPTA以及mLDFA进行相关性及回归分析。结果2组患者基线资料比较差异均无统计学意义(P值均>0.05)。KA组和MA组术前HKA(172.2°±5.3°、172.8°±4.6°)、mLDFA(88.9°±2.7°、90.4°±3.1°)、MPTA(84.8°±1.7°、84.4°±3.7°),以及术后HKA(175.8°±2.6°、176.3°±2.0°)、mLDFA(89.4°±2.7°、90.9°±2.4°)比较,差异均无统计学意义(t=0.35、1.58、0.37、0.68、1.76,P值均>0.05);术后MPTA测量值KA组(85.3°±1.8°)小于MA组(87.4°±2.1°),差异有统计学意义(t=3.33,P=0.002)。2组患者术后HKA均大于术前,且MA组术后MPTA也大于术前,差异均有统计学意义(P值均<0.01)。MA组MPTA矫正度数(4.3°±2.8°)大于KA组(1.9°±1.5°),差异有统计学意义(t=-3.25,P=0.003)。此外,KA组中术后mLDFA与术前mLDFA呈高度相关(R^(2)=0.79,P<0.001)。结论应用传统器械进行KA-TKA能够恢复患者术前股骨远端与胫骨近端关节线的解剖形态,术后患者胫骨近端关节线更内倾、股骨远端关节线更外翻,使得膝关节关节线与地面较MA-TKA更平行;而MA-TKA股骨假体放置更倾向于内翻。对于术后残留轻度内翻的TKA,采用KA方法与MA方法的内翻原因及程度不同,KA并不等同于残留内翻的MA。

Objective This study aimed to explore the changes in lower-limb alignment imaging parameters before and after kinematic alignment(KA)-total knee replacement(TKA)and mechanical alignment(MA)-TKA,as well as to analyze the causes of postoperative residual varus.Methods A retrospective cohort study was conducted on 36 patients who underwent TKA from June 2020 to January 2021 in the Department of Orthopedics,Beijing Chaoyang Hospital Affiliated to Capital Medical University.The patients included 17 males and 19 females aged 58-82 years old.During TKA,18 patients subjected to KA technique were included in the KA group,and 18 patients subjected to MA technique were included in the MA group.The baseline data of the patients including age,gender,body mass index,operative time,and lateral ratio were compared between the two groups.Hip-knee-ankle angle(HKA),medial proximal tibial angle(MPTA),medial lateral distal femoral angle(mLDFA),and the degree of correction were compared between the two groups pre-and post-operatively.Correlation and regression analyses were conducted on HKA,MPTA,and mLDFA in each group.Results No statistical significance was found in the comparison of baseline data between the two groups(all P values>0.05).Preoperative HKA(172.2°±5.3°vs.172.8°±4.6°),mLDFA(88.9°±2.7°vs.90.4°±3.1°),MPTA(84.8°±1.7°vs.84.4°±3.7°),and postoperative HKA(175.8°±2.6°vs.176.3°±2.0°),and mLDFA(89.4°±2.7°vs.90.9°±2.4°)in the KA and MA groups had no statistically significant difference(t=0.35,1.58,0.37,0.68,1.76,all P values>0.05).Postoperative HKA in both groups was higher than that before surgery,and postoperative MPTA in the MA group was higher than that before surgery;the differences were statistically significant(all P values<0.05).MPTA in the KA group was lower than that in the MA group(85.3°±1.8°vs.87.4°±2.1°),and the difference was statistically significant(t=3.33,P=0.002).MPTA correction degree in the MA group(4.3°±2.8°)was higher than that in the KA group(1.9°±1.5°),and the difference was statistically significant(t=3.25,P=0.003).Additionally,a high correlation existed between post-and pre-operative mLDFA in the KA group(R^(2)=0.79,P<0.001).Conclusion KA-TKA with traditional instruments can restore the preoperative anatomical morphology of the joint line of the distal femur and proximal tibia.The joint line of the proximal tibia is more inclined,and the joint line of the distal femur is more evaginated,thereby making the knee joint line more parallel to the ground than MA-TKA.MA-TKA femoral prosthesis placement is more prone to varus.Therefore,for TKA with mild residual varus after surgery,the reasons for the residual varus differed between KA-TKA and MA-TKA,and KA is not MA with residual varus.