PROGRESSION OF OSTEOPOROSIS IN CANCELLOUS BONE DEPENDING ON TRABECULAR STRUCTURE

Progression of osteoporosis is caused by a decline in bone formation a ctivity relative to the resorption activity. In this paper, the author s carried out a theoretical analysis of the progression of osteoporosi s to estimate the osteoporotic change in the upper end of the femur. A ccording to this analysis, the progression rate of osteoporosis in can cellous bone depends on the product of remodeling activity, R(act), an d the trabecular structure parameter, K-tr. To confirm that the theore tical results were reasonably comparable to actual osteoporotic change , these two factors were measured in rabbits. From the results, it was concluded that the highest progression rate was shown in bar/bar-like trabecular structure (type 3); the next highest rate, was shown in pl ate/bar-like structure (type 2); and the plate/plate-like structure (t ype 1) was the most insensible. Furthermore, the bone volume fractions of cancellous bone were measured at the upper end of human femurs wit h and without osteoporosis. Then the measured value was compared with the theoretical value for each type of trabecular structure. Results s howed that the decrease in bone volume fraction predicted by Eq. 7 was well in accord with the actual decrease.