Angle measurements of the distal radius: a cadaver study.

The quality of reduction of distal radius fractures is assessed mainly by degree of restoration of radial angle and palmar tilt. This cadaver study investigates the effects of forearm rotation of these measurements. A 5 degree rotational change produces a 1.6 degree change in palmar tilt on the conventional lateral view and a 1.0 degree change on the 15 degree lateral view. Lateral radiographs could be rotated 15 degrees-30 degrees and still be considered acceptable. Therefore, rotation may produce up to a 4.0 degree (15 degrees lateral view) or 6.4 degree (conventional lateral view) change in measured palmar tilt. To provide clearer measuring landmarks and minimize error due to rotation, we recommend obtaining the 15 degree lateral view routinely in fractures with significant dorsal angulation. We also studied the interobserver variability of different surgeons assessing radial angle and palmar tilt. The mean standard deviation between surgeons was 3.2 degrees for radial angle, 3.6 degrees for conventional lateral palmar tilt, and 2.1 degrees for 15 degrees lateral palmar tilt.