A study was performed to compare the degree of malreduction after intramedullary nail and plate fixation of the forearm and to determine if the degree of malreduction was clinically significant. Eight matched pairs of forearms, including the wrist and elbow joints, were harvested from cadaver upper extremities. The forearms were put through a full range of motion, and physiological loads were applied to simulate those during normal use. Standardized anteroposterior and lateral radiographs of each forearm were obtained with the specimen intact, and after an osteotomy and internal fixation of one bone, both bones, and with gap at the osteotomy sites. In each forearm pair, plating was randomly performed in one specimen and intramedullary nailing was performed in the matching contralateral specimen. Forearm architecture was assessed by quantification of the magnitude and location of maximum radial bow and radial angulation. In this study, plate fixation was superior to nail stabilization in restoration of the normal radial architecture. Plating did not change any of the radiographic indices (magnitude and location of maximum radial bow and radial angulation) at any stage of testing. None of the radiographic indices was changed by nailing of only one of the forearm bones. The magnitude of maximum radial bow and the radial angulation were changed by nailing both forearm bones after osteotomy and both forearm bones with a gap (p < 0.05). Despite this, both techniques were well within the limits of what is radiographically acceptable for reduction.(ABSTRACT TRUNCATED AT 250 WORDS)