In addition to bone density patterns and mechanical properties, subchondral bone also dynamically adjusts trabecular orientation and scale parameters in a precise relationship with principal stress. Subchondral bone is a very dynamic structure and is uniquely adapted to the mechanical forces imposed across the joint. It exhibits significant structural and mechanical anisotropy that is, the bone trabeculae shows preferential spatial orientation and parallelism. Subchondral trabecular bone has an inhomogeneous structure that varies with the distance from the articular surface. Relative to the subchondral bone plate, subchondral trabecular bone is more porous and metabolically active, containing blood vessels, sensory nerves, and bone marrow. Subchondral trabecular bone exerts important shock-absorbing and supportive functions in normal joints, and may also be important for cartilage nutrient supply and metabolism. Īrising from subchondral bone plate is the supporting trabeculae, which comprises subchondral trabecular bone, together with deeper bone structure. Channels are narrower and form a tree-like mesh in regions where the subchondral plate is thicker, while they tend to be wider and resemble ampullae where the plate is thinner. Channel shape and diameter also differs with the thickness of the cortical plate. These channels are preferentially concentrated in the heavily stressed areas of the joint. The distribution and intensity of the channels depend not only on aging, but also on the magnitude of the compressive forces transmitting through cartilage and subchondral bone within and between joints. A surprisingly high number of arterial and venous vessels, as well as nerves, penetrate through the channels and send tiny branches into calcified cartilage. It is invaded by channels that provide a direct link between articular cartilage and subchondral trabecular bone. This cortical endplate is not an impenetrable structure, but possesses a marked porosity. Subchondral bone plate is a thin cortical lamella, lying immediately beneath the calcified cartilage. Importantly, we focus on the microarchitectural and histopathological changes of subchondral bone in OA, and provide an overview of their potential contribution to the progression of OA. We also discuss factors that influence the integrity of subchondral bone. In this review, we summarize basic features of a functional joint unit comprised of subchondral bone and articular cartilage. Some histopathological changes in the subchondral bone have also been detected, including microdamage, bone marrow edema-like lesions and bone cysts. Despite the increase in the number of trabeculae and bone volume, subchondral bone is hypomineralized and of inferior quality, as a consequence of abnormal local high bone turnover. Subchondral bone deterioration is commonly associated with articular cartilage defects, and subchondral bone sclerosis, together with progressive cartilage degradation, is widely considered as a hallmark of OA. Īlthough OA has long been considered as a primary disorder of articular cartilage, the contribution of subchondral bone to the physiopathology of OA is arousing interest. As a slowly progressive degenerative joint disorder, OA is characterized by cartilage damage, changes in the subchondral bone, osteophyte formation, muscle weakness, and inflammation of the synovium tissue and tendon. Osteoarthritis (OA) is a common leading cause of pain and disability in the aging population. A hypothetical model for the pathogenesis of OA is proposed. We also focus on the microarchitectural and histopathological changes of subchondral bone in OA, and provide an overview of their potential contribution to the progression of OA. Importantly, we discuss risk factors influencing subchondral bone integrity. This review summarizes basic features of the osteochondral junction, which comprises subchondral bone and articular cartilage. Despite the increase in bone volume fraction, subchondral bone is hypomineralized, due to abnormal bone remodeling. Subchondral bone sclerosis, together with progressive cartilage degradation, is widely considered as a hallmark of OA. It is commonly reported to play a vital role in the pathogenesis of OA. Although OA has long been viewed as a primary disorder of articular cartilage, subchondral bone is attracting increasing attention. As a progressive degenerative joint disorder, OA is characterized by cartilage damage, changes in the subchondral bone, osteophyte formation, muscle weakness, and inflammation of the synovium tissue and tendon. Osteoarthritis (OA) is a major cause of disability in the adult population.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |