[Disuse osteoporosis].

Reduction of mechanical stress on bone inhibits osteoblast-mediated bone formation and accelerates osteoclast-mediated bone resorption, and leads to what has been called disuse osteoporosis. Prolonged therapeutic bed rest, immobilization due to motor paralysis from injury of the central nervous system or peripheral nerves, application of cast to treat fractures, a common causes of disuse osteoporosis. Imaging diagnosis shows coarse trabecular pattern and thinning of cortical bones. Bone metabolism markers have been used to evaluate bone metabolism. From the viewpoint of bone metabolism, antiresorptive agents should be administered to inhibit bone resorption. Rehabilitation, including bed positioning, therapeutic exercise and electrical stimulation, should be prescribed to subject the atrophied bone to an appropriate level of mechanical stress. In spite of these aggressive and continuous treatments, most cases of disuse osteoporosis require a long time for bone to recover its bone mineral density and strength. Hence, we have to keep in mind that there are no treatments better than prophylaxis of disuse osteoporosis.