Currently, the most common method for detecting prosthetic implant loosening is imaging. Unfortunately, imaging methods are imprecise in detecting the early signs of implant loosening. This paper describes a new wireless inductive proximity sensor system for detecting early implant loosening. The loosening of the implant is accurately detected by analyzing the electromagnetic field generated by the passive sensors located around the implant. The sensor system was modeled and simulated using COMSOL, and then tested experimentally. The inductive proximity sensor and the metallic implant form a coupled circuit is tuned to oscillate at a designed frequency. The circuit’s integrated controller measures and records specific sensor’s parameters such as resistance and inductance of the sensor that are directly related to the distance between the sensor system and the implant. A prototype has been developed and the results show that the designed proximity sensor is capable of measuring the loosening of the hip implant at $\text{50}\ \mu$m resolution at distances of less than $\text{8 mm}$, and of $\text{100}\ \mu$m resolution at a distance of $\text{15 mm}$. Furthermore, there is a good correlation between the simulated and experimental results.

中文翻译：

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一种植入式无线感应传感器系统，用于监测全关节置换手术中的假体运动

目前，检测假体假体松动的最常用方法是成像。不幸的是，成像方法在检测种植体松动的早期迹象方面并不精确。本文介绍了一种用于检测早期种植体松动的新型无线电感式接近传感器系统。通过分析位于植入物周围的无源传感器产生的电磁场，可以准确检测到植入物的松动。使用 COMSOL 对传感器系统进行建模和仿真，然后进行实验测试。电感式接近传感器和金属植入物形成一个耦合电路，被调谐到以设计频率振荡。该电路的集成控制器测量并记录与传感器系统和植入物之间的距离直接相关的特定传感器参数，例如传感器的电阻和电感。已经开发了原型，结果表明设计的接近传感器能够测量髋关节植入物的松动情况。$\text{50}\ \mu$米分辨率在小于 $\text{8 毫米}$，和 $\text{100}\ \mu$米分辨率距离 $\text{15 毫米}$. 此外，模拟和实验结果之间存在良好的相关性。