Altered Micromechanical Function Precedes Overt Surface Roughening in Early Cartilage Degeneration

The proper biomechanical functioning of articular cartilage in the joint is highly dependent on the composition and structure of the tissue. In the earliest stages of both osteoarthritis (OA) and age-related cartilage degeneration there are dramatic compositional and structural changes that occur within the general matrix. With these changes in matrix content and structure comes impaired biomechanical functioning [1]. A number of studies suggest that destructuring of the fibrillar collagen network (e.g., altered organization and loss of fibrillar interconnectivity) may be the initiating event in the degenerative cascade that leads to OA [2]. Despite the impact that these early structural changes have on bulk tissue mechanical properties, there have been few studies of the micromechanical consequences of matrix destructuring.