Huang YP, et al. - In this study, researchers utilized high-frequency ultrasound imaging (25 MHz) to scrutinize in vitro the tidemark in cylindrical osteochondral disks (n = 33) harvested from advanced osteoarthritis (OA) knees of humans. This preliminary study exhibited that morphology measured by high-frequency ultrasound imaging could reflect the quality of the subchondral bone. They concluded that the high-frequency ultrasound is a promising imaging tool to assess the changes of the subchondral bone in addition to those of the overlying cartilage in OA.