导航监测下股骨旋转角度及胫骨截骨后内翻角度对下肢动态力线的影响

目的 在计算机导航系统监测下模拟全膝关节置换术,观察不同股骨假体旋转角度及胫骨内翻角度对下肢动态力线的影响。方法 应用计算机导航技术于假骨上模拟人工全膝关节置换术,分别设定在股骨侧假体外旋不足及股骨侧假体过度外旋的情况下,设定胫骨截骨后内翻为0°、3°、5°不同角度时,活动膝关节记录膝关节0°、30°、60°、90°时下肢力线角度并进行分析,得到其变化的趋势和规律。结果 在股骨假体外旋不足的情况下,随着胫骨截骨后内翻角度的逐渐增大,下肢机械轴线内翻角度随之减少(P＜0.05或＜0.01);在股骨假体外旋不足的情况下,相同的胫骨截骨后内翻角度,在0～90°区间内下肢机械轴线内翻角度逐渐减少(P＜0.05);在股骨假体过度外旋情况下,随着胫骨截骨后内翻角度的逐渐增大,下肢机械轴线内翻角度随之增大(P＜0.05或＜0.01);在股骨假体过度外旋情况下,相同的胫骨截骨后内翻角度,在0～90°区间内下肢机械轴线内翻角度逐渐增大(P＜0.05)。结论 股骨假体旋转角度及胫骨内翻角度是影响下肢力线的重要因素。

Analysisi of the influence of femoral prosthesis rotation angle and tibia varus angle after tibial osteotomy on the mechanical axis alignment after computer-navigated assisted TKA

Objective To simulate total knee arthroplasty under the monitoring of the computer navigation system, and to observe the effects of different femoral prosthesis rotation angle and tibia varus angle on the mechanical axis alignment. Methods Total knee arthroplasty was performed on synthetic lower limb using computer navigation system. Mechanical axes at 0°,30°,60°and 90° were calculated when 0°,3°and 5° tibia varus under different femoral prosthesis malrotation, respectively, and the change trend and rule were obtained. Results Under the condition of insufficient external rotation of femoral prosthesis, the mechanical axis varus angle of lower limbs decreased with the increase of varus angle after tibial osteotomy(P＜0.05 or ＜0.01). In the case of insufficient external rotation of the femoral prosthesis, the varus angle of the lower limb gradually decreased within the interval of 0°～90° for the same posterior varus angle of the tibial osteotomy(P＜0.05). In the case of excessive external rotation of the femoral prosthesis, the varus angle of the lower limb increased with the gradual increase of the varus angle after the tibial osteotomy(P＜0.05 or ＜0.01). In the case of excessive external rotation of the femoral prosthesis, the varus angle of the lower extremity gradually increased within 0°～90° at the same posterior varus angle of the tibial osteotomy(P＜0.05). Conclusion Rotational alignment for femoral prosthesis and tibia varus were important factors in the achievement of accurate mechanical axis alignment.