Preliminary evidence that bilateral scaphoid symmetry is not affected by hand dominance or biological sex: volumetric and geometric analysis using high-resolution computed tomography with 0.5 mm slice-thickness

The scaphoid bone has a unique anatomy that can lead to complicated injury healing including non-union with or without avascular necrosis and subsequent complex operative treatment. The use of imaging of contralateral bones for operative planning and implant creation such as bone grafting relies on the innate symmetry of the human body. Previous studies of scaphoid anatomy have demonstrated symmetry in three-dimensional space and volume in right-hand dominant individuals. There is a gap in the literature reporting on scaphoid symmetry in left-hand dominant individuals. This study used the computed tomography (CT) scans of 30 healthy participants to create three dimensional (3D) models of left and right scaphoids to assess their symmetry. These bilateral models were quantified with respect to volume, surface area, length, and iterative-closest point (ICP). Paired-sample t-tests found differences in the volumes of contralateral scaphoids in males however surface area, length, and ICP of the scaphoids was observed to be not significantly different suggesting symmetry using these measures. In females, there was a significant difference in length but not the other measures. These results support further investigation using larger sample sizes and greater representation of left hand dominant participants into the use of contralateral scaphoid CT scans in pre-operative planning for the manufacture of patient-specific implants.