Quality of Healing Compared Between Osteoporotic Fracture and Normal Traumatic Fracture.

The major clinical consequence of osteoporosis in older people is osteoporotic fracture, which is difficult for fixation and poorer prognosis. Quality of life of patients after surgical intervention is largely affected. How the osteoporotic fracture healing differs from those of normal fracture healing or the nature of the characteristics of healing mechanism of osteoporotic fracture and its healing mode, have not been fully understood. In addition, there are no standards available to evaluate the quality of osteoporotic fracture repair, and the present clinical treatment for osteoporotic fracture is generally the same as that used for general traumatic fracture. Our research focused on studying healing mechanism and quality of osteoporotic fracture systemically at cellular, matrix, tissue, and organ levels compared between osteoporotic fracture rats and non-osteoporotic rats. These studies included evaluations of material property, geometrical morphology, microstructure, bone mineral metabolism, bone density, and mechanical strength of callus evaluated at different fracture healing stages. In order to provide above comprehensive information, we employed evaluation technologies, including transmit and polarized microscopy for histomorphometry, dual-energy X-ray absorptiometry (DXA) for bone mineral density (BMD), and mechanical testing. In addition, the results of our histological evaluations indicated both endochondral bone formation and intramembrane bone formation in osteoporotic fracture repair, yet endochondral bone formation and its ossification played a major role in the repair process. As compared with normal fracture healing, osteogenesis and endochondral ossification were delayed, whereas hard callus remodeling was accelerated, i.e., a faster bone turnover resulting in more bone resorption and less bone formation. In addition, the collagen fibers in the hard callus appeared loosely disorganized and irregular with regard to the direction of the principal stress. The abnormal change of the organizational constitution, microstructure, bone mineral metabolism, and bone mass in osteoporotic fracture repair could result in the decrease of its mechanical strength. [ABSTRACT FROM AUTHOR]