A follow-up study of 149 pediatric fractures of the femoral shaft (146 patients had a radiographic control) demonstrated a significant influence of multiple reductions and residual axial deviations on the incidence and extent of post-traumatic overgrowth. The presented group of patients did not show a positive correlation between therapeutic shortening at the time of the initial reduction and reduced incidence of long term overgrowth. Neither extent nor incidence of overgrowth could be prevented by this method. We therefore recommend to reduce fractures of the femoral shaft without forshortening, because it stimulates repair mechanisms at the growth plate and enhances overgrowth. In contradiction to the current concept of therapeutic recommendations it could be shown that post-traumatic rotational deformities will correct themselves in the course of physiologic detorsion of the femoral neck. In 67% of the studied group of patients initial errors of rotation corrected themselves by this mechanism. According to our results the therapeutic concept of pediatric femoral shaft fractures is revised and a new concept of initial and long term treatment is proposed.