A radiographic study of dorsovolar wrist axes and a database of angular measurements on axial computed tomography images.

OBJECTIVES

This study aims to identify the most accurate dorsovolar principal axis of the distal radius and carpus identified on axial computed tomography (CT) sections and to establish normative data for angular measurements among these axes.

PATIENTS AND METHODS

Between December 2019 and December 2021, normal axial CT images of wrists of a total of 42 individuals (25 males, 17 females; mean age: 31±8.4 years; range, 18 to 45 years) were retrospectively analyzed. Eight axes were identified on axial CT images: four distal radial axes (the volar cortical, medial cortical, central, and sigmoid notch axes) and four carpal axes (the scapholunate, lunotriquetral, capitohamate, and pisotrapezial axes). Twenty-two angular parameters were measured with reference to four principal axes (the volar cortical, medial cortical, central, and pisotrapezial axes).

RESULTS

The mean sigmoid notch rotation (version) angles relative to the four principal axes were 8±5° (range, -2° to 18°), 6±5° (range, -2° to 13°), 1±5° (range, -8° to 14°), and 4±4° (range, -3° to 15°), respectively. The mean scapholunate rotation angles were -13±5° (range, -27° to -6°), -15±6° (range, -29° to -8°), -21±5° (range, -30° to -11°), and -8±5° (range, -28° to -6°), respectively. Among four principal axes, the volar cortical and medial cortical axes were nearly collinear with both of relatively fixed carpal axes. The four principal axes showed angular differences between 2° and 8° with each other. There was no significant difference between men and women for all measurements.

CONCLUSION

The axial CT sections can be used to describe the various angulations between the normal wrist axes such as the sigmoid notch and scapholunate joint rotation angles. Despite slight differences among the four principal axes, the volar cortical and medial cortical axes are more consistent with the relatively fixed carpal axes.