Decrease of the electrical potentials measured on the surface of the knee and produced by cartilage compression during successive loading cycles

Abstract Electroarthrography (EAG) is a new technique for measuring electrical potentials appearing on the knee surface during loading that reflects cartilage quality and joint contact force. Our objective was to investigate the evolution of EAG signals during successive loading cycles. The study was conducted on 20 standing subjects who shifted their body weight to achieve knee loading. Their EAG signals were recorded during 10 successive loading cycles, and during a subsequent sequence of 10 cycles recorded after a 15 min exercise period. Multiple linear regression models estimated the electro-mechanical ratio (EMR) interpreting the ability of cartilage to generate a certain potential for a given ground reaction force by taking into account this force and the center of pressure displacements during unipedal stance. The results showed that the EMR values slowly decreased with successive cycles: during the initial sequence, the correlation coefficients between EMR values and sequence numbers were significant at 3 of the 4 electrode sites ( p