QUANTITATIVE CHARACTERIZATION OF COLLAGEN ORIENTATION IN THE SUPERFICIAL ZONE FOR STUDYING EARLY DEGENERATIVE CHANGES IN ARTICULAR CARTILAGE

Collagen fibres in the superficial zone are critical to the durability and stability of articular cartilage. Early osteoarthritis is often characterized by lesions on the surface of articular cartilage as a result of deterioration or degeneration of the collagen meshwork in the superficial zone. Therefore, traditional histology employing visual inspection of the microstructure of collagen fibres is one of the methods frequently used to evaluate the physiological state of articular cartilage in the medical field. However, traditional histology is often limited to 2D observations. It requires physical sectioning and dehydration of articular cartilage for stereological study. In addition, visual inspection is subjective and time consuming. Confocal microscopy provides a way to study the three-dimensional collagen structure in bulk hydrated articular cartilage. Utilizing fibre optical laser scanning confocal microscopy, the aim of the present study was to apply the spectral moment as a method for quantitatively describing the orientation of the collagen fibres in the superficial zone in relation to the physiological status of the cartilage, such as distinguishing normal cartilage from the early osteoarthritic cartilage.