Non-contact evaluation of osmosis-induced shrinkage and swelling behavior of articular cartilage in-situ using high-frequency ultrasound

The aim of the present study was to use high-frequency ultrasound for the investigation of the transient osmosis-induced free shrinkage-swelling behaviors of normal articular cartilage in situ . Full-thickness cartilage-bone specimens were prepared from normal bovine patellae. The transient shrinkage and swelling strains of the cartilage induced by changing the bathing solution between physiological saline (0.15 M) and hypertonic saline (2 M) were monitored using a 50 MHz focused ultrasound beam. Both shrinkage and swelling strains showed temporary overshoots, followed by relaxation phases. The absolute peak value of the shrinkage strain (1.01%0.62%) was significantly larger ( p This study successfully demonstrated that a high-frequency focused ultrasound beam could be used to monitor the transient osmosis-induced deformation of articular cartilage in a non-contact way. Since the osmosis-swelling behavior of cartilage relates to its compositional and structural characteristics and degeneration status, the reported ultrasound method may have potential for the characterization of cartilage degeneration, such as osteoarthritis.