title: Low-power circuits design for the wireless force measurement system of the total knee arthroplasty.
abstract: This paper proposes a novel wireless force measurement system for the Total Knee Arthroplasty (TKA) to improve the ligament balancing procedure during TKA. The force measurement system is comprised of a Wireless Force Measurement Spacer (WFMS) and the display part. They communicate with each other by the Radio Frequency (RF) signal. The WFMS is designed to measure the force between the WFMS and the femoral component of the artificial implants and to transmit the force data wirelessly by a low power transceiver. The display part demonstrates the force data in 3D images in real time. The WFMS composes of a sensors array, a Universal Transducer Interfaces (UTIs) array, a low-power sub-threshold microprocessor and a transceiver. The sub-threshold 8-bit microprocessor is taped out with 0.18 microm CMOS technology. The testing results of the microprocessor show that the leakage power of 46nW and the dynamic power of 385nW@165kHz are achieved with the operating voltage of 350 mV. The test results of the system are given and the errors of the system are analyzed. The results verified the reliability of the system. The future work is to design the microprocessor and a lower power transceiver within a single chip.
authors.affiliation: Institute of Microelectronics, Tsinghua University, Beijing 10084 China. hongchen@tsinghua.edu.cn
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.forename: Ming
authors.initials: M
authors.lastname: Liu
authors.forename: Weiyi
authors.initials: W
authors.lastname: Wan
authors.forename: Chen
authors.initials: C
authors.lastname: Jia
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.forename: Zihua
authors.initials: Z
authors.lastname: Wang
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation*; D011211:Electric Power Supplies; D006801:Humans; D008365:Manometry / Q000295:instrumentation*; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013314:Stress, Mechanical; D013686:Telemetry / Q000295:instrumentation*; D014159:Transducers