数字技术在个性化全膝关节置换下肢轴向力线控制中的应用

Application of digital technology in control of lower extremity axial alignment in personalized total knee arthroplasty

目的比较数字化技术和传统定位方法在进行全膝关节置换术（TKA）时对恢复下肢机械轴线的准确性。方法选取2013年2月至2015年4月膝骨性关节炎患者95例（100膝）进行前瞻性研究。随机分为传统手术组和数字化技术组,每组50膝。传统手术组中48例（50膝）,男21例（22膝）,女27例（28膝）,平均年龄年龄（68.4±7.2）岁,采用传统的标准TKA;数字化技术组中47例（50膝）,男20例（23膝）,女27例（27膝）,平均年龄年龄（69.3±8.2）岁,术前CT扫描和M imics软件建立患肢股骨和胫骨的三维模型,模拟术中截骨定位杆的使用,确定定位杆在股骨髁的进针点及＂术中股骨外翻角＂;在关节置换术中精确复制该过程进行股骨远端和胫骨平台的截骨;两组患者采用同一品牌关节假体,所有病例均为同一医师完成手术。两组病例术后均拍摄下肢全长正位X片,测量并比较股骨轴向力线与假体下缘连线的夹角（A角）,胫骨轴向力线与假体上缘连线的夹角（B角）,股骨轴向力线和胫骨轴向力线的夹角（C角）来验证下肢轴向力线的准确性。结果数字化技术组47例患者（50膝）＂术中股骨外翻角＂平均为5.83±1.85°（3.25°～9.36°）,术中均能很顺利地找到股骨和胫骨髓内定位杆进针点并进行手术,术后摄片测量平均A角为90.34°±1.61°（87.10°～92.88°）,B角为89.97°±1.37°（88.12°～92.33°）,C角为1.56°±0.72°（0.11°～2.59°）。传统手术组48例患者（50膝）平均A角为91.18°±2.20°（86.57°～94.59°）,B角为88.89°±3.25°（82.19°～92.30°）,C角为3.21°±1.56°（0.25°～6.32°）,差异有统计学意义。结论参照数字化技术模拟术中定位过程进行术前计划进行截骨可以更好地控制术后下肢轴向力线,有利于更加精确地进行个性化手术。

Objective To compare the accuracy of digital technology assisted total knee arthroplasty（TKA） with conventional positioning TKA for restoration of lower-extremity mechanical axis.Methods Ninety five patients（100 knees） undergoing TKA from February 2013 and April 2015 were randomly divided into the conventional surgery（CS） group（48 cases with 50 knees） and the digitaltechnology surgery（DS） group（47 cases with 50 knees）.For the DS group,the CT scan images of the lower extremity were obtained and mimics was used to reconstruct the three-dimensional model;according to the definition of axial alignment of the lower extremity,the entry points of femur and tibia were determined and the intraoperative femoral valgus angle was measured by simulating the intramedullary positioning rod;and the osteotomy at the distal femur and the proximal tibia was performed during the surgery.Patients of both groups used the same brand of joint prostheses and all operations were performed by the same surgeon.The angles A,B and C were measured from the X-ray images which were examined after the surgery to verify the accuracy of axial alignment of the lower extremity.Results The average of intraoperative femoral valgus angle of DS group was（5.83 ±1.85°）（3.25°-9.36°） and it was easy to be found the entry points in the surgery.The angles A,B and C were 90.34° ± 1.61°（87.10°-92.88°）,89.97° ± 1.37°（88.12°-92.33°）,and 1.56° ±0.72°（0.11°-2.59°） in CS group;the angles A,B and C were 91.18° ± 2.20°（86.57°-94.59°）,8.89° ± 3.25°（82.19°-92.30°） and 3.21° ± 1.56°（0.25°-6.32°）,respectively;the difference of two groups was statistically significant（P〈0.05）.Conclusion The study shows that simulating the intraoperative localization process in preoperative planning via digital technology can lead to better precision of axial alignment of the lower extremity.