Degenerative Changes in Articular Cartilage of Human Femoral Head Assessed Using Quantitative Ultrasonography: A Preliminary Study

Osteoarthritis (OA) is a progressive musculoskeletal disease which leads to chronic pain and functional impairment of the involved joint and negatively affects life quality. Degeneration of articular cartilage is one of main OA changes at tissue level. Quantitative ultrasound imaging (QUI) has been developed as a potential technique for evaluation of cartilage quality and diagnosis of OA. The aims of this study are to quantitatively assess the healthy and OA cartilage of human femoral head using QUI and to provide experimental data for future clinical studies. The cartilage samples of femoral head were prepared from human hip joint after patients were performed with joint replacement surgery. Four quantitative parameters including ultrasound roughness index (URI), reflection coefficient (RC), attenuation coefficient (α), cartilage thickness (h) were extracted from ultrasound signals acquired using Sonix RP diagnostic ultrasound system. It was found that in comparison with healthy cartilage, URI and α of the OA cartilage significantly increased (URI: from 59.56±16.17μm to 117.83±28.22μm; α: from 11.95±0.87 to 17.31±3.07, p < 0.05), whereas RC and cartilage thickness significantly decreased (RC: from 37.48±3.57 to 25.57±5.59; h: from 1.02±0.08 to 0.61±0.09, p < 0.05). In addition, the preliminary results indicated that the use of two of these parameters could classify cartilage samples into health and OA groups. Ultrasonic characteristics reflect the changes not only in the cartilage surface and but also in the whole tissue layer. This study may provide useful information for the quantitative ultrasonic diagnosis of OA in the hip joint in further studies.