The effects of distal radius fracture malalignment on forearm rotation: a cadaveric study.

Seven fresh cadaveric specimens were used to determine the loss of forearm rotation with varying 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, orienting the distal fragment position using an external fixator, and maintaining the position with wedges and a T-plate. 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. Dorsal tilt to 30 degrees 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%.