Pediatric both bone forearm fractures are generally treated with closed reduction and immobilization given the innate ability of the bone to remodel. Guidelines will vary by author, but fractures at any level in children less than 9 years of age, complete displacement, 15 degrees of angulation, and 45 degrees of malrotation are acceptable. In children 9 years of age and older, 30 degrees of malrotation, 10 degrees of angulation for proximal fractures, and 15 degrees for more distal fractures are acceptable. The cast index is defined as the sagittal width of the cast divided by the coronal width. If the fracture involves the physis, repeated closed reductions are not recommended due to potential injury of the physis. Therefore it is important to recognize acceptable alignment, know the potential for remodeling at certain ages, and the importance of a well-molded cast. Webb et al conducted a prospective, randomized study of 113 children who sustained fractures of the distal forearm. Patients were randomized to long arm or short arm casting. There was no difference in fracture displacement throughout the course of treatment. Loss of reduction was associated with poorly molded casts in both groups. The average cast index of patients who lost reduction was 0.79 compared to 0.70 in patients who did not lose reduction. Patients with short arm casts missed fewer school days and experienced less difficulty with activities of daily living. An example of the cast index from Webb's article is shown in Illustration A.
Waters PM, Mih AD. Forearm, wrist, and hand: pediatrics. In: Vaccaro AR, ed. Orthopaedic Knowledge Update 8. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2005:715-726.
Cornwall R, Waters PM. Pediatric trauma and infections. In: Trumble TE, Budoff JE, eds. Hand Surgery Update 4. Rosemont, IL: American Society for Surgery of the Hand; 2007:745-753.
Webb GR, Galpin RD, Armstrong DG. Comparison of short and long arm plaster casts for displaced fractures in the distal third of the forearm in children. J Bone Joint Surg Am. 2006 Jan;88(1):9-17.
PMID:16391244 (Link to Abstract)