Epiphyseal distraction and centrally located bone bar: an experimental study in the rabbit

The purpose of this study was to analyze the force required for an epiphysiolysis in vitro in the distal femoral growth plate of rabbits with different sized central physeal bone bars. The bars were operatively induced by drilling through the physis. An epiphyseal distraction was then performed, and the response was evaluated. Forty rabbits (67 femurs) divided into five groups were used for experimentation. Group A had not been operated on and manifested no physeal bone bridge. Groups B, C, D, and E manifested some bone bridges obtained surgically by drills 2, 2.5, 3.5, and 4.5 mm in diameter, respectively. The average force required to obtain an epiphysiolysis is not statistically significant in the different groups. However, we noted that the epiphysiolysis differed depending on the diameter of the surgically performed bridge. Group E was Salter-Harris type II fractures, whereas groups A, B, and C were type I fractures. Group D comprised both types.