Related Experiment Video
Updated: May 10, 2026
Development of a Novel Internal Fixation Model for Rat Radial Fractures: Fracture Healing Assessment and Dorsal Root Ganglion Isolation
Published on: March 13, 2026
3-Dimensional deformity analysis of malunited forearm diaphyseal fractures
Junichi Miyake1, Kunihiro Oka, Toshiyuki Kataoka
1Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan. miyake-osk@umin.ac.jp
Purpose:
Several biomechanical studies using cadavers have revealed that axial rotation deformity of the forearm bones reduces forearm motion. However, little information is available on the 3-dimensional deformity patterns, including axial rotation deformity in malunited diaphyseal fractures of the forearm. The complex deformity of both forearm bones is difficult to assess on plain radiographs or cross-sectional images. Therefore, we assessed osseous deformity in malunited diaphyseal fractures of the forearm using 3-dimensioinal analysis.
Methods:
We examined 21 patients (16 malunions of both forearm bones and 5 isolated radial malunions). Three-dimensional computer models of bilateral radius and ulna were created from computed tomography data. We evaluated deformity by superimposing the mirror-image bone model of the contralateral normal bone onto a model of the affected bone.
Results:
In 21 radial malunions, extension (n = 17) and pronation (n = 16) deformities were common. This tendency was seen particularly in proximal malunions. Average extension, valgus, and pronation deformities were 18°, 2°, and 16°, respectively. In 16 ulnar malunions, valgus (n = 15) and pronation (n = 12) deformities were common. Average flexion, valgus, and pronation deformities were 1°, 11°, and 6°, respectively. Extension deformity of the radius and valgus deformity of the ulna were correlated with restriction of forearm motion.
Conclusions:
Malunited diaphyseal fractures of both forearm bones showed complex deformities, which suggests that 3-dimensional modeling may be a more effective method than standard computed tomography or radiographs. Pronation deformity of the radius may be caused by the supinator and pronator muscles. In addition, the deformity pattern of both bones may indicate that valgus and internal rotation force in the neutral forearm position is applied to both forearm bones after injury.
Clinical Relevance:
Three-dimensional forearm osteotomy, including rotational realignment, is necessary to obtain anatomical reduction.
Related Concept Videos
01:15Bones of the Upper Limb: Ulna
01:09Functional Classification of Joints
The functional classification of joints is determined by the amount of mobility between the adjacent bones. Joints are functionally classified as a synarthrosis or immobile joint, an amphiarthrosis or slightly moveable joint, or as a diarthrosis, a freely moveable joint. Fibrous and cartilaginous joints can be functionally classified as either synarthroses or amphiarthroses, whereas all synovial joints are classified as diarthroses.
Synarthrosis
An immobile...
01:19Bones of the Upper Limb: Humerus
01:27Fractures: Bone Repair
Minor fractures with no bone displacement are treated by immobilizing the fractured bone using a cast or splint. However, in the case of fractures with displaced bones, the broken bones are repositioned before immobilization to ensure successful healing without deformation and loss of function. The realignment of fractured bone ends is performed through a process called reduction. If the procedure...
01:09Bones of the Upper Limb: Radius
The radius has a nail-shaped head, and a short...