Rat femur
Alle deler > BILL > Studier > Osteoporose
Finsen V:
STRENGTH OF THE RAT FEMUR ONE YEAR AFTER FRACTURE.
Int J Orthop Trauma 2: 228-32, 1992
In 26 anesthetized rats an elastic steel wire was peroperatively passed through the major trochanter and into themedullary canal of the femur. In 20 animals closed midshaftfractures were performed, while the remainder served as controls.The wires were removed after 36 days. X-rays were made at intervals. Six animals died before the end of the study.
The maximal transectional callus area decreased gradually between the 5th and the 55th postoperative week when the animals were killed. At this time the fracture areas were still not fully remodeled. Three point bending tests showed that the medullary nailing alone resulted in no permanent change in mechanical properties. The strength of the fractured femora was reduced by only 5% (p=0.065) compared to the contralateral side, while stiffness was reduced by 11 % (p=0.006), deflection by 23% (p=0.001), and energy absorbed before failure by 40% (p=0.001).
Even after one year the fractured femora thus had decreased ability to withstand forces which might produce fracture.