[Osteoporosis in the absence of support for the extremity]

In dogs, the lower part of the right extremities was amputated, thus generating a support-free state of the femur. On day 90 after the amputation bone resorption reached a high level and by the end of the year declined. The mature bone microstructures showed a higher degree of mineralization, whereas the young bone microstructures which were in predominance in the support-free femur displayed a lower degree of mineralization. In bone, the content of Ca decreased, that of K increased, while the content of Na and P remained unchanged. The development of osteoporosis in the support-free femur did not involve only quantitative variations in the mineral component.