[Bisphosphonate therapy for osteoporosis and bone strength].

Bisphosphonates are now the most widely used drugs for osteoporosis. When bisphosphonate is given, the response varies directly with the rate of bone turnover at baseline. In high turnover osteoporosis there could be a gain in bone mass, but it reach a plateau after 2 to 3 years. In normal or low turnover osteoporosis bone mass is stabilized or slightly increased. The best indication of bisphosphonate use for osteoporosis is high turnover. In high turnover osteoporosis bisphosphonate therapy is effective in increasing the stiffness and the toughness (bone strength) by increasing the mean degree of mineralization of bone tissue through the prolongation of secondary mineralization. But the long-term use of bisphosphonate would result in highly mineralized bone and disturbed repair of microcracks by inhibition of bone remodeling. Intermittent use of bisphosphonate could be recommended to avoid the deterioration of bone quality.