Development of a non-invasive bio-acoustics measurement system for assessing articular cartilage knee joint problem

Abstract

A technique in measuring and recording of bio-acoustics signals for the assessment of physiological of knee joint articular cartilage conditions has been developed. Currently, invasive technique such as knee arthroscopy and IMAGING modalities methods are widely been applied in determining problems related to the knee joint. However, these methods are uncomfortable to the patient, performing in static condition, costly instrumentation and maintenance and most of the times it could not reveal the early symptoms of knee articular cartilage problems. Knee acoustical is used to overcome the current practice limitation and could assist physicians to diagnose at the early stage. The measurement system is developed which consists of a high-sensitivity acoustical piezoelectric transducer with frequency response ranges from 2.5 to 5000Hz, the signal conditioning circuit, and real-time signal visualization and analyzed using a short time Fourier transform technique. The knee cartilage produced an acoustic signals are measured non-invasively during a dynamic cycle of flexion-extension and sit-stand-sit movements. This paper also describes the details of hardware components and software used in this system. Six volunteers with normal and injured cartilage involved in this study. The normal conditions of the knee articular cartilage produced a lower frequency component which is less than 120Hz, and abnormal signal shows frequency more than 200Hz is generated. It has been demonstrated that, the developed system prototype could be used to differentiate between normal and abnormal knee articular cartilage acoustic signal using frequency spectral which could be beneficial in the early detection of the problem.