Abstract
The purpose of this study is to more accurately determine distal radius articular
step-off in the posteroanterior (PA) view. A cadaveric forearm was osteotomized with
varying amounts of articular displacement. A second osteotomy was made through the
distal radius metaphysis to create four positions of tilt in the lateral plane (5°
and 15° dorsal tilt; 5° and 15° volar tilt). Using fluoroscopy, the beam was positioned
in the lateral plane from 25° volar to 20° dorsal, separated by 5° increments, obtaining
modified PA images of the distal radius in its various configurations. The images
were randomly evaluated for step-off by three hand surgeons in a blinded fashion.
Statistical analysis was performed to determine the accuracy between estimated and
actual step-off and was demonstrated to be greater when the PA view was parallel to
the distal radius tilt in the lateral plane, for all four configurations of distal
radius tilt. Data pertaining to the distal radius with 0 mm of step-off did not demonstrate
the PA view, parallel to the distal radius tilt, to be superior than the PA views
not parallel to the tilt; reaffirming that with anatomic reduction, any fluoroscopic
image exhibits good alignment. This study confirms that the most accurate method of
accessing PA step-off is to first determine the tilt of the radius on a lateral film
and then align the beam in the PA plane to match this tilt.
Keywords
distal radius fractures - articular surface - step-off - tilted radiographs
