An implantable telemetry device to measure intra-articular tibial forces
An implantable telemetry device to measure intra-articular tibial forces
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DOI：
10.1016/j.jbiomech.2004.02.011
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发表时间：
2005-02-01
影响因子：
2.4
通讯作者：
Colwell, CW
中科院分区：
文献类型：
--
作者：
D'Lima, DD;Townsend, CP;Colwell, CW
胫骨力很重要，因为它决定了聚乙烯的磨损、植入物中的应力分布以及向底层骨的应力转移。根据所使用的数学模型和所分析的活动类型，胫骨股骨力的理论估计在体重的3到6倍之间变化。因此，开发了一种植入式遥测系统来直接测量胫股压缩力。该系统在一具尸体膝盖上进行了动态膝盖测试。一个全膝关节胫骨置换假体在胫骨托盘的四个角安装了四个力传感器。这些传感器测量胫骨托盘上的总压缩力和压力中心的位置。微处理器执行模数信号转换，并执行表面声波射频振荡器的脉冲编码调制。然后，该信号通过位于茎尖的单针密封馈电钽线天线传输。无线电频率信号由连接到接收器和计算机的外部天线接收，用于数据采集。假体由外部线圈感应供电。胫骨换能器精确地测量了精确施加的外部载荷的大小和位置。射频信号通过尸体骨骼、骨水泥和软组织成功传输至3米范围。在测量通过聚乙烯嵌套施加的载荷时获得了合理的精度。该植入物还能够检测单髁负载与升降。(C) 2004 Elsevier Ltd.版权所有。
Tibial forces are important because they determine polyethylene wear, stress distribution in the implant, and stress transfer to underlying bone. Theoretic estimates of tibiofemoral forces have varied between three and six times the body weight depending on the mathematical models used and the type of activity analyzed. An implantable telemetry system was therefore developed to directly measure tibiofemoral compressive forces. This system was tested in a cadaver knee in a dynamic knee rig. A total knee tibial arthroplasty prosthesis was instrumented with four force transducers located at the four corners of the tibial tray. These transducers measured the total compressive forces on the tibial tray and the location of the center of pressure. A microprocessor performed analog-to-digital signal conversion and performed pulse code modulation of a surface acoustic wave radio frequency oscillator. This signal was then transmitted through a single pin hermetic feed-through tantalum wire antenna located at the tip of the stem. The radio frequency signal was received by an external antenna connected to a receiver and to a computer for data acquisition. The prosthesis was powered by external coil induction. The tibial transducer accurately measured both the magnitude and the location of precisely applied external loads. Successful transmission of the radio frequency signal up to a range of 3 m was achieved through cadaveric bone, bone cement, and soft tissue. Reasonable accuracy was obtained in measuring loads applied through a polyethylene insert. The implant was also able to detect unicondylar loading with liftoff. (C) 2004 Elsevier Ltd. All rights reserved.