Radiographic assessment of longitudinal growth of the rabbit femoral physes.

Using surgically implanted metal markers, serial radiographs of 17 immature femurs were evaluated for growth of the entire femur and of the distal femoral physis in rabbits 20 to 100 days of age. From these data the rate of longitudinal growth was plotted. The most rapid growth during the study period was from 20 to 40 days. Growth rates reached a plateau at 100 days of age. The increases in length for unit of time were compared for the entire femur and the distal physis. The distal physis was responsible for approximately 65-70% of the femoral growth for the study period. As an internal control of reproducibility of measurement, two means of determining distal femoral growth rates were compared. Their best fit curves proved to be almost identical. The model of evaluation of femoral growth is reproducible and can serve as a control against which variables in growth can be compared.