Spectral analysis of knee vibroarthrographic signals in asymptomatic chondromalacia patella

Early stage of chondromalacia patella is usually asymptomatic. Detection of chondromalacia patella sooner can delay further cartilage degeneration by appropriate exercise prescription and behavioral change. The purpose of this study is to preliminary examine asymptomatic subjects and investigate the knee vibroarthrographic (VAG) signals in order to suggest possible parameters to detect chondromalacia patella at the early stage. Frequency characteristics of the signals which include energy and the summing of spectral power in each 500 Hz frequency band were observed. Energy and spectral power of the VAG signals with chondromalacia patella were obviously higher than normal VAG signals, particularly in the high frequency bands (higher than 500 Hz). VAG signal is therefore a promising tool in detection of early stage chondromalacia patella.