Measurement of the mechanical properties of regenerated articular cartilage using wavelet transformation

Tissue regeneration is one of the effective options to treat articular cartilage damage because the cartilage has little ability to repair itself. To assess the results of the regenerative treatment, the mechanical properties of the regenerated articular cartilage must be measured. In this study, a new method using wavelet transformation of ultrasonic reflected wave was proposed to achieve the measurement of the mechanical properties of the regenerated articular cartilage. The ultrasonic reflected wave involves the mechanical properties of a measured material. The information of the mechanical properties is obtained by various analyses. In this study, wavelet transformation was used. The wavelet transformation is one of the time-frequency analyses and widely used in various fields. The wavelet map from wavelet transformation compared the mechanical properties from the indentation test, thickness from the histological study and surface roughness. The present method could measure the aggregate modulus, surface roughness and thickness. The regenerated articular cartilage, which was cultured for 4 weeks, was a lower aggregate modulus than that of native articular cartilage. The present method can non-invasively measure the mechanical properties in a short time. It suggests that the follow-up of regenerative treatment for damaged articular cartilage can be performed.