[An experimental study of bone remodeling influenced by mechanical stress]

Bone remodeling influenced by mechanical stresses was studied using ambulatory chickens. They were divided into four groups with the different mechanical forces applied to the leg. I: running along a circular track, II: walking or standing on one leg, III: control, IV: casting. The animals were sacrificed after 12 weeks and undecalcified cross-sections of femurs and tibias were examined using a tetracycline labeling method. Bone formation was evident at both metaphyses of the femur and at the proximal metaphysis of the tibia. More bone formation was observed at the medial quarter of both femur and tibia than in comparison with the lateral quarter. There was, however, no difference in the membraneous ossification between the medial and lateral quarters in Group II. The lack of significant cortical drift at the medial side of the femur and tibia suggests that no bending moment is generated by standing on one leg.