Shear Wave Ultrasound Elastography for Estimating Cartilage Stiffness: Implications for Early Detection of Osteoarthritis

Current osteoarthritis (OA) diagnosis relies on radiographic abnormalities found in later stages of the disease, posing a challenge to the treatment efficacy. Therefore, earlier detection of OA is essential for improving therapeutic outcomes. The aim of this study was to investigate the feasibility of shear wave ultrasound elastography (SWUE) to detect changes in cartilage mechanical properties under OA conditions ex-vivo. Bovine osteochondral units were harvested from femoral condyles and subjected to either trypsin degradation, cartilage surface roughness defect using varying degrees of sandpaper, or subchondral bone degeneration using formic acid (FA) injection. Shear waves were generated using a mechanical shaker, while a high-frequency ultrasound system operating at 18 MHz was employed to detect wave propagation along the samples. The elasticity of cartilage was estimated by the shear wave speed (SWS) through the auto-correlation method. Our results show that the estimated SWS of cartilage after 24, 48, and 72 hours of trypsin incubation significantly decreased by 37 • Shear wave ultrasound elastography noninvasively measure the elastic properties of soft tissue. • Increasing cartilage surface roughness and enzyme degradation results in slower shear wave speeds. • Subchondral bone degradation increases shear wave speed in cartilage. • Shear wave ultrasound elastography is a novel method for early osteoarthritis diagnosis.