计算机辅助与传统方法全膝关节置换术术后下肢机械轴的比较研究

Comparison of the mechanical axis of lower extremity after total knee replacement with and without computer-aided navigation

目的对比计算机辅助下（导航）全膝关节置换术及同期传统方法全膝关节置换术术后下肢轴线的差异。方法连续无选择病例30例39膝在计算机导航下行全膝关节置换术并与同期采用传统方法连续无选择的全膝关节置换术29例39膝进行对照。分别拍摄术后膝关节正侧位X线片、双下肢全长X线片，分别记录两组的术后下肢轴线与股骨及胫骨解剖轴线的关系，并对两组进行比较。结果导航组术后机械轴范围176°-185°，平均180．3°±1．79°。传统组术后机械轴范围176°-187°，平均181．32°±2．51°。两组样本，采用独立样本t检验，t=2．45，P〈0．05，差异有统计学意义。其中：术后机械轴偏差0°（180°）导航组10／39膝（25．64％），传统组9／39膝（23．08％），经卡方检验，χ2=0．07，P〉0．05，差异无统计学意义。偏差≤±1°（179°-181°）导航组27／39膝（69．23％），传统组16／39膝（41．03％），X。=6．27，P〈0．05，两组差异有统计学意义。偏差≤±3°（177°-183°）导航组36／39膝（92．31％），传统组29／39膝（74．36％），χ2=4．52，P〈0．05，两组差异有统计学意义。偏差≥±4°（≤176°或≥184°）导航组为3膝（7．69％），传统组为10膝（25．64％），χ2=4．51，P〈0．05，两组差异有统计学意义。结论计算机辅助下（导航）行全膝关节置换术术后下肢机械轴明显优于传统方法。边缘值（大于184°及小于176°）明显低于传统组。

Objective To compare the mechanical axis of lower extremity after total knee replacement with computer-aided navigation and that with conventional surgery, an retrospective review study was conducted. Methods Thirty-nine knees in 30 consecutive patients were treated by total knee arthroplasty with computer-aided navigation, while 39 knees in 29 patients with conventional surgery in the corresponding period. The full-length radiography of the lower extremity as well as AP and lateral plain X-ray of the knee joints was measured before and after operation. The difference of mechanical axis was compared. Resuits The mechanical axis angle in navigation group was ranged from 176° to 185°（mean, 180.3°±1.79°） and the conventional group was ranged from 176° to 187° （mean, 181.32°±2.51°） . There were 10 knees （25.46%） in navigation group and 9 knees （23.08%） in conventional group with a deviation of 0°. There were no significant differences between two groups by chi-square test. Between the cases with deviation of 1°, There were 27 knees （69.23%） in computer-aided group and 16 knees （41.03%） in conventional group and significant differences was observed （P〈0.05） between two groups. That was confirmed after comparing the case with deviation≤ 3° （92.31% versus 74.36%） （P〈0.05） and 〉 4°（7.69% versus 25.64%） （P〈0.05）. Conclusion The total knee replacement surgery with computer-aided navigation improved accuracy of correction that of the mechanical axis of lower extremity compared with conventional surgery. The cases over the limit value （〈176° or 〉186°） in computer-aided group were obviously less than in the conventional group.