Arc center distance as a novel quantitative radiographic parameter for volar Barton fractures.

Purpose: The aims of this study were to investigate conventional radiographic parameters and introduce a novel parameter (arc center distance, ACD) for volar Barton fractures.

Methods: Twenty-four cases of volar Barton fracture were retrospectively analyzed. We measured volar tilt angle (VTA), anteroposterior distance (APD), teardrop angle (TDA), and capitate-to-axis-of-radius distance (CARD) on lateral plain radiographs. The ACD was measured on the sagittal images of computed tomography scans. VTAs, APDs, TDAs, and CARDs were compared between the fractured and normal contralateral wrist. The area under the receiver operating characteristic curve was calculated for each parameter.

Results: TDAs did not differ significantly between the fractured wrists and the controls. On the other hand, VTAs, APDs, and CARDs were all significantly greater in the fractured wrists (mean values were 17.25°, 20.70 mm, and - 3.40 mm, respectively). The area under the curve value was highest (0.943) for the ACD. When a cutoff value of 1.02 mm was used as a threshold, a sensitivity of 100% and specificity of 80.95% were achieved.

Conclusions: The mean values of conventional parameters (VTA, APD, TDA and CARD) in volar Barton fractures were presented. The ACD can be useful parameter for quantitatively evaluating volar Barton fractures.