Roentgen recognition of acute plastic bowing of the forearm in children.

Traumatic bowing of one or both forearm bones in children represents an acute plastic deformation of bone. Plastic curvatures have been produced in the dog ulna, but have been recognized only recently in man. The biomechanics and histologic changes of the experimental model explain the roentgenological features found in children with traumatically bowed bones: (1) broad fixed curvatures which hold fractures in angulation and resist orthopedic reduction; (2) absence of periosteal new bone formation following the injury; and (3) partial correction of the plastic corvature by cortical remodeling in young children. In a series of 17 patients, eight children had bowing of the ulna with an angulated fracture of the radius, five had bowing of the radius with an angulated ulna fracture, and four children had both the radius and ulna bowed without fracture. Manipulative reduction in the majority of children with fractures failed to reduce the plastic curvature, causing partial loss of pronation and supination.