Background: 

An accelerometer-based portable navigation system was recently introduced to improve prosthetic alignment during total knee arthroplasty (TKA). The purpose of this multicenter prospective randomized controlled trial (RCT) was to evaluate the effects of this accelerometer-based portable navigation system for achieving more accurate alignment during TKA in the clinical setting.

Methods: 

One hundred patients with primary varus osteoarthritis of the knee were enrolled in this prospective RCT conducted in 5 hospitals. A navigation system was utilized in 50 patients (navigation group), and a conventional intramedullary femoral guide and an extramedullary tibial guide were utilized in 50 patients (conventional group). At 6 months postoperatively, weight-bearing radiographs were obtained of the whole operative leg. An experienced surgeon who was blinded to the treatment assignments then measured the alignment to 1 decimal place with use of computer software. Power analysis showed that 41 knees were required in each group.

Results: 

There were no complications as a result of the use of the accelerometer-based portable navigation system. Postoperative radiographs were obtained in 45 patients from each group. There were no significant differences in sex, age, height, body weight, body mass index, preoperative femorotibial angle, and operative time between groups. The absolute differences of the femoral prosthesis (p = 0.01), tibial prosthesis (p < 0.01), and hip-knee-ankle angle (p < 0.01) from a neutral mechanical axis were less in the navigation group compared with those in the conventional group. Alignment outliers (>2° away from the neutral mechanical axis) of the tibial prosthesis and hip-knee-ankle angle were less in the navigation group (9% and 27%, respectively) compared with those in the conventional group (31% and 49%; p = 0.01 and p = 0.04, respectively).

Conclusions: 

To our knowledge, this is the first multicenter prospective RCT to evaluate an accelerometer-based portable navigation system. An accelerometer-based portable navigation system provides more accurate prosthetic and limb alignment in the coronal plane than conventional techniques, without extended operative time or an increased rate of complications. The results of this study may help orthopaedic surgeons decide whether or not to use an accelerometer-based portable navigation system.

Level of Evidence: 

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

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基于加速度计的便携式导航系统在全膝关节置换术中的用途：多中心前瞻性随机对照试验

背景： 

最近引入了基于加速度计的便携式导航系统，以改善全膝关节置换术（TKA）期间的假体对齐。这项多中心前瞻性随机对照试验（RCT）的目的是评估这种基于加速度计的便携式导航系统在临床环境中TKA期间实现更准确对准的效果。

方法： 

在5所医院进行的这项前瞻性RCT纳入了100例膝关节原发性内翻性骨关节炎患者。50例患者（导航组）使用了导航系统，而50例患者（常规组）使用了常规的髓内股骨引导器和髓外胫骨引导器。术后6个月，获得了整个手术腿的负重X光片。一位经验丰富的外科医生对治疗工作不知情，然后使用计算机软件将对齐方式测量到小数点后一位。力量分析表明，每组需要41个膝盖。

结果： 

由于使用了基于加速度计的便携式导航系统，因此没有任何并发​​症。每组45例患者均获得了术后X线照片。两组之间的性别，年龄，身高，体重，体重指数，术前股骨角和手术时间无明显差异。导航组的股骨假体（p = 0.01），胫骨假体（p <0.01）和髋膝踝角（p <0.01）的绝对差值比常规方法小组。导航组的胫骨假体对准误差（距中性机械轴> 2°）和髋膝踝角分别比常规组（31％和27％）少（分别为9％和27％） 49％； p = 0.01和p = 0.04）。

结论： 

据我们所知，这是第一个评估基于加速度计的便携式导航系统的多中心预期RCT。与传统技术相比，基于加速度计的便携式导航系统可在冠状平面内提供更准确的假肢和四肢对准，而无需延长手术时间或增加并发症的发生率。这项研究的结果可能有助于骨科医生决定是否使用基于加速度计的便携式导航系统。

证据级别： 

治疗I级。有关证据水平的完整说明，请参见《作者说明》。