Implant failure can have devastating consequences on patient outcomes following joint replacement. Time to diagnosis affects subsequent treatment success, but current diagnostics do not give early warning and lack accuracy. This research proposes an embedded ultrasound system to monitor implant fixation and temperature – a potential indicator of infection. Requiring only two implanted components: a piezoelectric transducer and a coil, pulse-echo responses are elicited via a three-coil inductive link. This passive system avoids the need for batteries, energy harvesters, and microprocessors, resulting in minimal changes to existing implant architecture. Proof-of-concept was demonstrated in vitro for a titanium plate cemented into synthetic bone, using a small embedded coil with 10 mm diameter. Gross loosening – simulated by completely debonding the implant-cement interface – was detectable with 95% confidence at up to 12 mm implantation depth. Temperature was calibrated with root mean square error of 0.19°C at 5 mm, with measurements accurate to ±1°C with 95% confidence up to 6 mm implantation depth. These data demonstrate that with only a transducer and coil implanted, it is possible to measure fixation and temperature simultaneously. This simple smart implant approach minimises the need to modify well-established implant designs, and hence could enable mass-market adoption.

中文翻译：

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简单的智能植入物：使用嵌入式超声换能器同时监测骨科的松动和温度

植入失败会对关节置换后的患者结果产生破坏性后果。诊断时间影响随后的治疗成功，但目前的诊断不能提供早期预警并且缺乏准确性。这项研究提出了一种嵌入式超声系统来监测种植体固定和温度——感染的潜在指标。只需要两个植入组件：一个压电换能器和一个线圈，脉冲回波响应是通过一个三线圈电感链接引起的。这种无源系统避免了对电池、能量收集器和微处理器的需求，从而对现有植入结构的改动最小。概念验证被证明体外用于将钛板粘合到合成骨中，使用直径为 10 毫米的小型嵌入式线圈。通过完全剥离种植体-水泥界面模拟的严重松动在种植深度达 12 毫米时以 95% 的置信度被检测到。温度在 5 毫米处以 0.19°C 的均方根误差进行校准，测量值精确到 ±1°C，在 6 毫米植入深度内具有 95% 的置信度。这些数据表明，仅植入换能器和线圈，就可以同时测量固定和温度。这种简单的智能植入方法最大限度地减少了修改完善植入设计的需要，因此可以实现大众市场的采用。