HISTOLOGICAL AND RADIOGRAPHIC DETERMINATION OF THE AGE OF PHYSEAL CLOSURE OF THE DISTAL FEMUR, PROXIMAL TIBIA, AND PROXIMAL FIBULA OF THE NEW-ZEALAND WHITE-RABBIT

A longitudinal study was performed in a series of 124 New Zealand Whit e rabbits to determine the radiographic versus the histologic age of c losure of the growth plates of the distal femur, proximal tibia, and p roximal fibula. Periodic assessment was made by standard radiographs a nd histological studies. Histologically growth plates in the distal fe mur closed at 19-24 weeks; growth plates in the proximal tibia, at 25- 32 weeks; and growth plates in the proximal fibula, at 26-32 weeks. Ra diographically, evidence of closure of growth plates in the distal fem ur occurred at 20-23 weeks; in the proximal tibia, at 22-27 weeks; and in the proximal fibula, at 23-31 weeks. A discrepancy in age between radiographic and histologic closure of the growth plate occurred in 3. 6% of the femora, 10.9% of the tibias, and 16% of the fibulas.