[Validation of the Tekscan system for statistic and dynamic pressure measurements of the human femorotibial joint]

Abstract

In vitro dynamic pressure measurements in the healthy and pathologically altered knee joint help to improve our understanding of the loading pattern on femorotibial surfaces. The aim of the study was to evaluate a piezoresistive pressure measuring system. A human cadaveric knee was mounted in a material-testing machine (Bionix 858) using a specially designed knee-holding device. Axial loading of the knee, flexed at 20o, at 500 N, 1000N and 1500 N was then carried out. For the static investigations, the piezoresistive measuring system (Tekscan), was compared with the FUJI measuring system. In addition, dynamic measurements were also performed with the Tekscan System. With the exception of the lateral compartment at a load of 1500 N, no differences in maximum pressures were observed between the two systems. Nor were there any differences with regard to contact surfaces, either in the medial or lateral compartment (p > 0.05). However, the reproducibility of the data was significantly higher with the Tekscan System (p < 0.01). Dynamic pressure measurements obtained with the knee flexed 20 to 90o showed that the lateral contact area shifted from anterior to posterior, while the medial contact area remained virtually unchanged. The Tekscan System proved to be more reliable than the FUJI System, and permits simultaneous measurements in both compartments. The Tekscan System is suitable for dynamic measurement of the femorotibial joint, and permits measurements to be made under more physiological conditions.