Analysis of high frequency acoustic emission signals as a new approach for assessing knee osteoarthritis

Acoustic signal analysis offers a potential scientific basis for new, convenient, non-invasive tools to monitor the dynamic integrity of joints. The rationale is that smooth, optimally lubricated surfaces slide quietly against each other whereas rough, suboptimally lubricated surfaces move unevenly, producing acoustic signals. To investigate this, we used wide-band piezoelectric transducers to detect sound waves with frequencies up to 400 kHz (a well-established technique for evaluating the integrity of engineering structures1) emitted during knee movement. The Joint Acoustic Analysis System (JAAS) comprises a laptop controlling a data acquisition system connected to two acoustic emission (AE) sensors and an electrogoniometer. While each AE sensor is fastened inferior to the patella of each knee and anterior to the