Comparison of acoustical parameters of knee sound according to pathological condition for pattern extraction

Considerable noise is sometimes associated with degeneration of the knee joint surface. Such noise may indicate roughness or softening of the cartilage surfaces, and may be a useful index for early disease. In this study, we have evaluated and classified arthritic pathology using the acoustical analysis of knee joint sounds. Six normal subjects and 11 patients with knee problems were enrolled. Patients were divided into the 1st patient group which required an orthopeadic surgery due to ruptured wounds of the meniscus or Anterior Cruciate Ligament (ACL) and the 2nd patient group of osteoarthritis. During sitting and standing periods, subjects' active knee flexion and extension were monitored. The data of sounds and angle of knee joint were collected. We analyzed the fundamental frequency (F ₀), mean amplitude (A ₀), jitter and shimmer of each group in the middle of sitting and standing. As a result, F0, jitter and shimmer of control group in standing was larger than values in sitting. This result is same as experimental group. Next, we analyzed the parameters in sitting and standing among 3 groups. As a result, the parameters of the 2nd patient group were larger than values of control group regardless of their positions. However, the parameters of the 1st patient group in any position were smaller than values of control group. These results suggest that an analysis of knee joint sound might assist non-invasive diagnosis of an articular pathology.