Purpose

The purpose is to verify the intra- and inter-operator reliability of an extramedullary (EM) accelerometer-based smart cutting guide for distal femoral resection during primary total knee arthroplasty (TKA). The hypothesis of the present study was that the use of the device would result in a good correlation between different operators with a difference between repeated measurements of less than 1°.

Methods

Twenty-five not consecutive patients with knee osteoarthritis undergone to primary TKA using an EM inertial-based cutting guide to perform distal femoral resection. In order to assess the agreement in femoral axis definition of the device, two operators performed three time each the manoeuvres necessary to define axis. Inter-rater agreement was evaluated with Bland and Altman agreement test. Intra-rater repeatability was evaluated analysing average results distribution of repeated measurements. Accuracy of the device was evaluated comparing differences between intra-operative device data with final implant alignment measured on post-operative longstanding x-rays using Students’ t test.

Results

Agreement between the two operators was statistically significant (p < 0.05) with a bias of − 0.4° (95% CI − 0.6° to − 0.2°). Average difference between cut orientation measured with device and final implant position, measured on x-rays, was 0.2° (95% CI − 1.5° to 1.7°) with no statistical difference between the two measurements. Final implant alignment, measured on x-ray, was 90.2°, with 95% of cases distributed within range 88.0° to 92.0° for varus-valgus and 2.8° and with 95% of cases distributed within range 2.0° to 4.0° for flexion–extension.

Conclusions

The EM accelerometer-based smart cutting guide used to perform distal femoral resection during primary TKA demonstrated a good intra- and inter-operator reliability in the present in vivo study.

中文翻译：

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一种新型基于髓外加速度计的全膝关节置换术智能切割导向器的内部和内部操作员可靠性评估：一项体内研究

目的

目的是验证在初次全膝关节置换术 (TKA) 期间用于股骨远端切除术的基于髓外 (EM) 加速度计的智能切割导向器在操作者内部和操作者之间的可靠性。本研究的假设是，使用该设备会导致不同操作员之间的良好相关性，重复测量之间的差异小于 1°。

方法

25 名非连续性膝骨关节炎患者使用基于 EM 惯性的切割导向器进行初次 TKA 以进行股骨远端切除术。为了评估设备股骨轴定义的一致性，两名操作员各执行了 3 次定义轴所需的操作。评估者间的一致性通过 Bland 和 Altman 一致性测试进行评估。通过分析重复测量的平均结果分布来评估评估者内的可重复性。通过比较术中设备数据与使用学生t检验在术后长期 X 射线上测量的最终植入物对齐之间的差异，评估了设备的准确性。

结果

两位操作员之间的一致性具有统计学意义 ( p  < 0.05)，偏差为 − 0.4°（95% CI − 0.6° 至 − 0.2°）。用设备测量的切割方向与在 X 射线上测量的最终种植体位置之间的平均差异为 0.2°（95% CI - 1.5° 至 1.7°），两次测量之间没有统计学差异。在 X 射线上测量的最终种植体排列为 90.2°，其中 95% 的病例分布在 88.0° 至 92.0° 的内翻-外翻和 2.8° 范围内，95% 的病例分布在 2.0° 至 4.0° 的屈曲范围内-扩大。

结论

在目前的体内研究中，用于在初次 TKA 期间进行股骨远端切除术的基于 EM 加速度计的智能切割导向器展示了良好的操作者内部和操作者间可靠性。