数字技术在个性化全膝关节置换股骨轴向力线控制中的应用

目的 应用数字技术设计＂术中股骨外翻角＂来指导全膝关节置换中股骨远端截骨,以期获得良好的股骨轴向力线.方法自2012 年3月至2013 年 7 月收治膝骨关节炎患者共 26例（28 膝）,男 11 例（13 膝）,女15例（15 膝）,年龄58～85岁,平均70.1岁,在术前CT扫描其双下肢,用Mimics软件建立并获得患肢股骨的三维模型.在三维模型中根据下肢轴向力线的定义,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精确测量出＂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的截骨.术后拍摄下肢全长正位片,测量术后股骨机械轴和股骨假体下缘连线的夹角来验证股骨轴向力线的准确性.结果 26例患者（28膝）均行术前设计,测量＂术中股骨外翻角＂平均为（5.67°±1.82°）（3.25°～9.36°）,术中均能很顺利的找到髓内定位杆进针点并进行手术,术后摄片测量股骨机械轴和股骨假体下缘连线的夹角为（90.9°±1.84°）（87.1°～92.8°）.结论 参照数字技术设计的＂术中股骨外翻角＂进行截骨可以很好地控制术后下肢股骨侧的轴向力线,有利于更加精确的进行个性化手术.

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

Objective To design the ＂intraoperative femoral valgus angle＂ via digital technology in order to guide the osteotomy in the total knee arthroplasty （TKA） for good axial alignment. Methods Between March 2012 and July 2013, 26 patients （28 knees） with knee osteoarthritis were included in this study, among which there were 11 males （13 knees） and 15 females （15 knees）.The average age was 70.1 years old （range, 58-85 years）.The CT scan image data of both lower limbs were obtained from 26 patients （28 knees）. Mimics was used to read the data and reconstruct the three dimensional （3-D） model of the femur. According to the lower extremity axial alignment definition, the entry point was determined and the ＂ intraoperative femoral valgus angle＂ was measured accurately by simulating the intramedullary positioning rod. The distal femoral osteotomy was performed during the surgery. The angle between the femoral mechanical axis and the lower edge of the femoral prosthesis were measured from the X ray images which were examined after the surgery to verify the accuracy of axial alignment of the femur. Results 26 patients （28 knees） underwent the preoperative design; the average of the ＂intraoperative femoral valgus angle＂ was （5.67°±1.82°） （3.25°-9.36°）. It was easy to find the entry point in the surgery. The angle between the femoral mechanical axis and the lower edge of the femoral prosthesis according to the X ray after surgery was （90.9°±1.84°） （87.1°-92.8°）. Conclusion In our study, using the ＂intraoperative femoral valgus angle＂ in TKA led to better precision of the femoral component position and was in favor of more accurate personalized operation.