Osteoporosis influences the late period of fracture healing in a rat model prepared by ovariectomy and low calcium diet

To elucidate the influence of osteoporosis on the fracture healing, we produced a rat osteoporosis model by ovariectomy and by maintaining a low calcium diet; and monitored the healing process radiographically, histologically, and biomechanically for 12 weeks. Radiologic, histologic and biomechanical findings of the fracture areas 6 weeks after making the fractures were almost identical in both the osteoporosis group and the control group. However, 12 weeks after making the fractures, newly generated bones in the osteoporosis group showed histological osteoporotic changes and their bone mineral density on the fracture site decreased. These findings show that estrogen-deficient and low calcium conditions greatly affect the bone in the later period of the healing process, but do not affect remarkably the early healing period. This is clinically important when we consider fracture treatments for patients with osteoporosis due to menopause. (C) 1999 Elsevier Science Ltd. All rights reserved.