Quantitative arthroscopic ultrasound evaluation of living human cartilage

Objective. To investigate whether living human articular cartilage can be evaluated quantitatively by means of a new diagnostic technique that introduces an ultrasonic probe into the knee joint under arthroscopy and then analyzes the A-mode echogram by means of wavelet transformation. Design. Intact and injured sites of living human articular cartilage were evaluated under arthroscopy. The maximum magnitude and the echo duration (defined as the length of time that included 95% of echo signal) were selected as the quantitative indices on the wavelet map. Background. Quantitative evaluation of articular cartilage in situ has the potential to contribute to our understanding of cartilage breakdown and to the effectiveness of cartilage regeneration. However, a reliable method of quantitative cartilage evaluation has yet to be developed for clinical use. Methods. Living human articular cartilage was analyzed using an ultrasonic probe under arthroscopy and the cartilage characteristics on the echo duration–maximum magnitude graph were examined. Results. Unlike the L-shape distribution of human cadaver cartilage data, the distribution of the living human articular cartilage data showed a smooth curve with a steep initial gradient that flattens gradually at the highest value of echo duration on the echo duration–maximum magnitude graph. Conclusions. The present study suggests a new quantitative evaluation system for articular cartilage with clinical potential.