Use of Tekscan pressure sensors for measuring contact pressures in the human knee joint

Abstract

The Tekscan pressure sensor is a common instrument to quantify in vitro tibiofemoral and patellofemoral contact pressures, which helps to understand the impact of surgical intervention such as total knee arthroplasty (TKA). As a result of the non-linear behavior of the sensor, the conditioning, normalization and calibration of the sensor are critical to achieve correct measurements. In this paper, a literature review is presented that provides insight in the correct use of these sensors, resulting in optimal accuracy. To guarantee the repeatability of the measurements, a secure and correct fixation of the sensor in the joint is required. Using the sensor for intra-articular measurements induces several unintended effects, which potentially lower the accuracy of the measurement. First, the uneven surface can result in wrinkling and destruction of the sensor, in turn leading to measurement results that can be corrupted. Second, the presence of shear forces on the sensor can lead to wear of the sensor and reduction in sensitivity with loss of accuracy as a result. Also the fixation method can worsen the accuracy. In literature, a deterioration of the accuracy from 3% under optimal conditions to errors of more than 50% are reported as a result of the aforementioned effects.