Longitudinal growth pattern of the radius after forearm fractures conservatively treated in children

In a 3-year prospective study, the growth pattern of the radius following fracture was analyzed in 64 children < 15 years old with forearm fractures treated by conservative methods. Comparative radiographic studies of the fractured and the uninjured radius were carried out in all patients at 3, 6, 12, and 18 months after fracture. Only 40 patients, 28 boys and 12 girls, with an average age of 9 years, completed the follow-up period. The series included 19 buckle fractures of the radius, 11 green-stick, and 10 complete fractures. Fracture of the ulna was associated in 11 cases. Maximal average radial growth rate was observed from age 9 through 12 years. Overall, the length discrepancy between the fracture and the healthy radius at the end of the follow-up period averaged 0.03 cm (range -0.50 to +1). In nine cases (21%), the fractured radius showed an average overgrowth of +0.44 cm. In 10 other patients (25%), a radial shortening could be detected (average discrepancy -0.29). Five of the nine cases with radial overgrowth had an associated fracture of the ulna. This association was not found in any of the 10 patients with radial shortening. These observations allow us to reconsider the classic etiopathogenic theories concerning overgrowth in the long bones of children following fracture. Factors other than the increased vascularity of the growth plate--as is postulated for the femur and tibia--must be investigated further to explain the frequent absence of radial overgrowth following fracture.