Distal Radius Malunion and Forearm Rotation: A Cadaveric Study

Abstract

Background Malunions following distal radius fractures are common, with shortening, translation, and rotation occurring. The patients frequently lose forearm rotation, but there is no data to indicate whether this is due to mechanical misalignment between the radius and the ulna or to contracture of the soft tissues.

Material and Methods Seven fresh cadaveric specimens were used to determine the loss of forearm rotation with varying simulated distal radius fracture malalignment patterns. Uniplanar malunion patterns consisting of dorsal tilt, radioulnar translation, or radial shortening were simulated by creating an osteotomy at the distal end of the radius.

Description of Technique By orienting the distal fragment position using an external fixator and maintaining the position with wedges and a T-plate, varying degrees of malunion of the distal radius could be simulated. Rotation of the forearm was produced by fixing the elbow in a flexed position and applying a constant torque to the forearm using deadweights. Forearm rotation was measured with a protractor.

Results Dorsal tilt to 30° and radial translation to 10 mm led to no significant restriction in forearm pronation or supination ranges of motion. A 5-mm ulnar translation deformity resulted in a mean 23% loss of pronation range of motion. Radial shortening of 10 mm reduced forearm pronation by 47% and supination by 29%.

Conclusion Because a severe osseous misalignment was required to produce a significant loss in rotation, contracture of the soft tissues is most likely the cause of the loss of rotation in most cases.

Keywords

allograft - artilage - thumb arthritis - ligament - stability

• References

• 1 Cole JM, Obletz BE. Comminuted fractures of the distal end of the radius treated by skeletal transfixion in plaster cast. An end-result study of thirty-three cases. J Bone Joint Surg Am 1966; 48 (5) 931-945 [Case Reports]
• 2 Peltier LF. Fractures of the distal end of the radius. An historical account. Clin Orthop Relat Res 1984; (187) 18-22 [Biography Historical Article]
• 3 Cooney III WP, Dobyns JH, Linscheid RL. Complications of Colles' fractures. J Bone Joint Surg Am 1980; 62 (4) 613-619
• 4 Fernandez DL. Correction of post-traumatic wrist deformity in adults by osteotomy, bone-grafting, and internal fixation. J Bone Joint Surg Am 1982; 64 (8) 1164-1178
• 5 Flinkkilä T, Raatikainen T, Kaarela O, Hämäläinen M. Corrective osteotomy for malunion of the distal radius. Arch Orthop Trauma Surg 2000; 120 (1-2) 23-26
• 6 Park MJ, Cooney III WP, Hahn ME, Looi KP, An KN. The effects of dorsally angulated distal radius fractures on carpal kinematics. J Hand Surg Am 2002; 27 (2) 223-232
• 7 Tarr RR, Garfinkel AI, Sarmiento A. The effects of angular and rotational deformities of both bones of the forearm. An in vitro study. J Bone Joint Surg Am 1984; 66 (1) 65-70
• 8 Jupiter JB, Ruder J, Roth DA. Computer-generated bone models in the planning of osteotomy of multidirectional distal radius malunions. J Hand Surg Am 1992; 17 (3) 406-415
• 9 Crisco JJ, Moore DC, Marai GE , et al. Effects of distal radius malunion on distal radioulnar joint mechanics—an in vivo study. J Orthop Res 2007; 25 (4) 547-555
• 10 Matthews LS, Kaufer H, Garver DF, Sonstegard DA. The effect on supination-pronation of angular malalignment of fractures of both bones of the forearm. J Bone Joint Surg Am 1982; 64 (1) 14-17