Development of a device to detect sound from knee joint of patients before and after surgery

This paper presents development of a device to detect knee sound signals for distinguish between normal subjects, patients with osteoarthritis before surgery and patients with osteoarthritis after surgery. Knee sound signals generated by knee movement so it difference in normal knee joint and degeneration of the knee joint surface. We detected the acoustical parameters, such as the fundamental frequency (F0), the mean amplitude of the pitches, the efficiency of F0 and the efficiency of A0. We compared them with three groups. We record knee sound from 36 normal subjects, 5 patients with osteoarthritis before surgery and 3 patients after surgery in two positions (sitting and standing). The mean values of F0 and A0 of the normal group were larger than other group. These result shows good potential for early detection between normal subject and patients with osteoarthritis before surgery and after surgery.