计算机导航对人工全膝关节置换术下肢旋转对线的影响

The effect of computer assisted navigation on axial alignment of lower extremity in total knee replacement

目的对比分析计算机导航人工全膝关节置换术与标准人工全膝关节置换术对假体旋转对线、术后下肢力线、假体位置及功能恢复的影响。方法将82例患者随机分为两组进行前瞻性对照研究。对照组采用标准全膝关节置换手术，导航组采用计算机导航人工全膝关节置换术。CT测量两组患者术后股骨假体旋转角、胫骨假体旋转角、假体的联合旋转角及假体之间的相对旋转角；X线片上测量两组下肢冠状面力线，假体在冠状位、矢状位的位置。记录术后6周、6个月的膝关节活动范围、KSS评分、Oxford评分及髌股关节评分。结果对照组和导航组术后股骨假体平均旋转角分别为1．51°±3．55°和-0．63°±3．04°，假体联合旋转角为2．85°±4．07°和0．28°±3．43°，假体之间的相对旋转角为1．44°±4．55°和-0．43°±2．86°，差异均有统计学意义（P〈0．05）。两组之间胫骨假体旋转角差异无统计学意义。术后x线片测量结果显示，导航组下肢冠状面力线、股骨假体冠状面位置优于对照组。功能评分显示，术后6周导航组优于对照组，术后6个月两组差异无统计学意义。结论导航可以避免假体旋转不良，改善下肢旋转对线及冠状面力线，有助于术后早期功能恢复。

Objective To compare the effect between computer assisted navigation total knee replacement and conventional total knee replacement on rotation alignment, mechanical axes, component posi- tion and clinical outcomes. Methods Eighty-two patients were recruited into this prospective study accord- ing to entry criteria and were randomly selected into either control group which treated with standard knee replacements or navigation assisted group which operated with navigation assisted total knee replacements. To analyze the rotation of the femoral component and the tibial component in the transverse plane, the com- bined rotation of both components and mismatch between two components, the mechanical axes, which were measured from postoperative radiographs and computed tomography images. To compare the functional out- comes at 6 weeks and 6 months. Results There were significant differences （P〈 0.05） in following parame- ters between control group and navigation assisted group： average rotation of femoral component were 1.51°± 3.55° in control group and -0.63°±3.04° in navigation assisted group, the combined rotation of both compo- nents were 2.85°±4.07° in control group and 0.28°±3.43° in navigation assisted group, mismatch between components were 1.44°±4.55° in control group and -0.43°±2.86° in navigation assisted group. There were no significant differences between two groups in rotation of tibial component. In addition, analysis showed that patients in navigation assisted group had significantly better mechanical axes and functional outcomes at 6 weeks. Conclusion The use of navigation can help avoid malrotation and errors in axial rotation, and pro- vides improved alignment accuracy as well as better functional outcomes at 6 weeks.