Abstract
Intro
Distal radial fractures are a commonly encountered fracture & anatomical reduction is the standard. Dorsal angulation is the traditional method of assessment but is inaccurate in rotated lateral xrays. Previously a relationship has been demonstrated between the dorsal cortex (DC) of the radius & the superior pole of the lunate (SL) & its sensitivity for assessing dorsal angulation & translation.
Hypothesis
A constant anatomical relationship maintained between the DC and the SL when rotated up to 30 degrees from standard lateral?
Methods
MRI scans of 28 wrists including the distal third of the radius to the proximal carpal row. Beginning 5cm proximal to the distal radius articular surface, a line was superimposed upon the DC extending distally through the metaphysis. Lunate height (LH) & distance from the DC line to the SL (DC-SL) were measured at 5-degree rotational increments around the radial shaft central axis to 30 degrees of supination & pronation (S+P). The DC-SL/LH ratio was compared to 0 degrees (anatomical lateral) using the two-tailed paired student t-test.
Results
No significant difference in DC-SL:LH between 0 degrees of rotation and any 5-degree increment up to 30 degrees of S+P (lowest p=0.075). The DC line lay consistently dorsal to the SL.
Conclusion
A constant DC-SL relationship is maintained with up to 30 degrees of S+P. This reference can be quickly and accurately used to assess DRF reduction in poorly-taken films with malrotation.
