内翻型弓形股骨对膝骨性关节炎下肢力线的影响

Varus Femoral Bowing Impairs Lower Limb Alignments in Osteoarthritic Knees

目的探讨股骨弓形形态与股骨远端关节线方向的相关性。方法纳入2018年至2019年因膝骨性关节炎在我院行初次全膝关节置换的病例共126例(187膝),其中男39例(47膝),女87例(140膝),年龄为(68.1±3.7)岁(61~79岁)。术前均拍摄下肢全长片。收集术前胫股机械轴内侧角(HKA)、股骨弓形角(FBA)、股骨下段外翻角(dAMA)、股骨远端关节线外侧机械角(mLDFA)、胫骨近端关节线内侧机械角(mMPTA)以及胫股关节线夹角(JLCA),依据FBA大小分为显著弓形组(FBA>4°)、轻度弓形组(4°≥FBA>2°)、非弓形组(2°≥FBA≥0°)。比较上述形态学参数的组间差异,并分析显著弓形组内各参数相关性。结果显著弓形组内股骨弓形、股骨下段外翻、股骨侧关节线内翻以及膝内翻最显著(FBA=5.1°±0.6°,dAMA=7.0°±1.6°,mLDFA=94.5°±1.0°,HKA=171.4°±4.3°,P<0.001);而非弓形组内胫骨侧关节线内翻和胫股关节面内翻最显著(mMPTA=86.7°±1.6°,P<0.05;JLCA=-4.4°±2.5°,P<0.001)。显著弓形组内FBA与m LDFA存在较强相关性(r=0.607,P<0.01)。结论弓形股骨与膝骨性关节炎的股骨关节线内翻显著相关,并使下肢整体内翻增加。

Objective To explore the potential connection between femoral bowings and distal femoral joint line orientations.Methods The study enrolled 126 patients(187 knees)of primary total knee arthroplasty(TKA)due to primary knee osteoarthritis in our hospital during the year 2018-2019 with routine preoperative whole limb radiographs,including 39 males(47 knees)and 87 females(140 knees),aged(68.1±3.7)(61-79)years old.The collected individual morphological variables were pre-operative hip-knee-ankle(HKA),femoral bowing angle(FBA),distal femoral anatomic-mechanic angle(dAMA),mechanical lateral distal femoral angle(mLDFA),mechanical medial proximal tibial angle(mMPTA)and joint line convergence angle(JLCA).All cases were divided into three groups:conspicuous femoral bowings(group A,FBA>4°),mild femoral bowings(group B,4°≥FBA>2°),and minimal bowing femurs(group C,2°≥FBA≥0°).The intergroup differences of the above morphological parameters were compared,and the bivariate correlations of the parameters were analyzed within the group A.Results Greater femoral bowings,greater distal femoral valgus anatomic orientation,greater varus femoral joint line orientation and greater genu-varus deformity were demonstrated in group A(FBA=5.1°±0.6°,dAMA=7.0°±1.6°,mLDFA=94.5°±1.0°,HKA=171.4°±4.3°,P<0.001).The greater varus tibial joint line orientation and greater varus femoral-tibial joint line angulation were found in group C(mMPTA=86.7°±1.6°,P<0.05;JLCA=-4.4°±2.5°,P<0.001).FBA presented a strong positive correlation with mLDFA(r=0.607,P<0.01).Conclusion Femoral bowing was strongly correlated with varus orientation of distal femoral joint line,accompanied by a featured varus deformity in the lower limb alignment.