[Experimental study on internal fixation with screws through femoral epiphyseal plate].

Objective: To explore the effect of internal fixation with screw through femoral epiphyseal plate on growth in- hibition via an experimental study.

Methods: Forty New Zealand rabbits were randomly divided into 4 groups and 10 rabbits in each group. Epiphyseal plate was injured by penetrating of screws, and the size of damage area was controlled by changing the number of threads. Group A: blank group; group B: injury area accounted for 4% of the epiphyseal plate; group C: injury area accounted for 6%; group D: injury area accounted for 8%. The internal fixation was removed after 2 weeks, and the results were observed with X-ray film for 4 groups to judge the complications such as early closure of epiphyseal.

Results: In each group, there were no statistical differences in the length of the femoral neck, the diameter of femoral neck, the diameter of the femoral head, and the epiphyseal plate closure time. The growth speed of the length and diameter of the femoral neck, as well as the diameter of femoral head, were quicker on the early phase, and the speed was slowest when the epiphyseal plate was being closed.

Conclusion: The injury area of epiphyseal plate under 8% is safe for its growth. Because no evidences demonstrate the growth inhibition of epiphyseal plate, the screws can be used for rabbit epiphyseal plates.