目的回顾性评价电磁导航辅助全膝关节置换( total knee arthroplasty，TKA )术后假体植入和重建下肢力线的准确性，探讨应用电磁导航系统施行全膝关节置换术的技术特点和早期临床疗效。方法对2006年7月至2007年2月电磁导航辅助初次 TKA 的初始连续病例64例100膝进行回顾性研究，男7例，女57例；年龄57～79岁，平均66.9岁。术后观察导航时间，止血带时间、出血量和48 h 引流量。X 线评估包括测量术前和术后3个月下肢机械轴线角，股骨、胫骨假体的冠状面倾斜角(α角和β角)和股骨假体矢状面倾斜角(γ角)。内翻表示为“+”，外翻表示为“-”。观察手术前、术后3个月的 KSS 评分膝关节功能、膝关节屈伸活动度( ranges of motion，ROM )和并发症。结果导航时间为(10±2) min/膝，止血带时间为(93±9) min。48 h 出血量、引流量为(483±55) ml。手术前后机械轴线角分别为(+8.07±6.69)°，(+1.20±1.92)°，两者差异有统计学意义( P＜0.05)。术后α角为(89.33±1.64)°，β角为(89.64±1.47)°，γ角为(90.86±2.37)°，术前和术后3个月 KSS 评分分别为(86±18)分和(137±26)分，两者差异有统计学意义( P＜0.05)。术前和术后3个月 ROM 分别为(92±21)°和(108±24)°，差异有统计学意义( P＜0.05)。术后下肢机械轴线、α角、β角和γ角与术后 KSS 评分、ROM 间的相关性均无统计学意义( P＞0.05)。术后无感染、血管神经损伤、骨折、下肢深静脉血栓形成等并发症发生。结论电磁导航系统是安全可靠的，应用该系统行 TKA 可获得理想的假体位置和下肢力线，以及早期优良的临床疗效。“,” Objective To retrospectively evaluate the accuracy of postoperative prosthesis implantation and reconstruction of lower limb alignment after total knee arthroplasty ( TKA ) using an electromagnetic ( EM ) navigation system, and to investigate the technical characteristics and early clinical results of EM navigation assisted TKA. Methods The data of 64 initial consecutive patients ( 100 knees ) who underwent primary TKA using an EM navigation system from July 2006 to February 2007 were retrospectively studied. There were 7 males and 57 females, whose mean age was 66.9 years old ( range; 57-79 years ). The navigation time, tourniquet time, blood loss and drainage flow in 48h were observed after the operation. The mechanical axis angle of the lower extremity, the coronal inclination angle of femoral and tibial prostheses and the sagittal inclination angle of femoral prostheses (α,βandγangles ) were measured based on X-rays before the operation and at the 3rd month after the operation. Varus was expressed as positive (+) and valgus negative (-). The knee function was evaluated using the Knee Society Score ( KSS ) before the operation and at the 3rd month after the operation, and the knee joint flexion and extension range of motion ( ROM ) and complications were also recorded. Results The navigation time was ( 10±2 ) min for each knee, and the tourniquet time was ( 93±9 ) min. The blood loss and drainage flow in 48 h were ( 483±55 ) ml. The preoperative and postoperative mechanical axis angles were (+8.07±6.69 ) ° and (+1.20±1.92 ) ° respectively, and statistically significant differences were found between them ( P<0.05 ). The postoperativeαangle,βangle andγangle were ( 89.33±1.64 ) °, ( 89.64±1.47 ) ° and ( 90.86±2.37 ) ° respectively. The KSS scores were ( 86±18 ) points and ( 137±26 ) points respectively before the operation and at the 3rd month after the operation, and statistically significant differences were found between them ( P<0.05 ). The ROM were ( 92±21 ) ° and ( 108±24 ) ° respectively before the operation and at the 3rd month after the operation, and statistically significant differences were found between them ( P0.05 ). No complications such as infection, injuries of nerves and blood vessels, bone fractures, deep venous thrombosis of the lower extremity and so on were found. Conclusions The EM navigation system is safe and reliable. With the EM navigation system in TKA, optimal prosthesis position and lower limb alignment and good early clinical results can be achieved.