Histological observation on the mode of healing of experimental osteoporotic fracture

Objective To dynamically observe the histological alterations and characteristics of osteoporotic fracture healing, and to further elucidate its mode of healing. Methods 80 female 8 month old SD rats were randomized into two groups of 40 each: the osteoporotic fracture model(OPFM) and the common fracture model(CFM). The callus of each rat was examined by light microscope or polarized microscope in 5 days and 2,4,6,8,12 and 16 weeks postoperatively. Results In OPFM, both endochondral bone formation and intramembrane bone formation played their parts in osteoporotic fracture healing, the former played a major role. But during the healing process, endochondral bone formation delayed, while bony callus tissue remodeling accelerated(bone resorptionbone formation), collagenous fibers in callus tissue arranged loosely and irregularly in and being in consistent with the direction of the principal stress. Conclusion Compared with the common fracture healing, quality of the osteporotic fracture healing can decrease. (Shanghai Med J. 1999,22:137 139)