Abstract
Introduction
Surgeons fixing scaphoid fractures need to be familiar with its morphological variations and their implications on safe screw placement during fixation of these fractures. Literature has limited data in this regard. The purpose of this CT-based study was to investigate scaphoid morphometry and to analyse the safe trajectories of screw placement in scaphoid.
Methods
We measured the coronal and Sagittal widths of scaphoid in CT-scans of 60 patients using CT based data from 50 live subjects with intact scaphoid. Safe placements for screws with diameters of 1.7mm, 2.4mm, 3.5mm and 4mm were studied using trajectories with additional 2mm safety corridor.
Results
The mean width of proximal segment in coronal and sagittal plane were 6.39mm (4.5–8.7) and 11.44mm (8.4–14.1) respectively. For the waist region, the mean coronal, sagittal width were 8.03mm (6.3–10.2mm) and 9.02mm (7–11.4mm) respectively. For distal segment, the mean coronal and sagittal width were 10.58mm (8.2–14.6mm) and the 9.59mm (7.3–11.9mm) respectively. The coronal and sagittal widths were significantly different from each other in all three zones. All scaphoid were capable of safely containing single 4mm screw and two parallel 1.7mm screws.
Conclusion
Our study shows that there is considerable variation in scaphoid morphometry. Among the parameters, the waist region measurements show the least variation. The screw lengths do not always correlate to the overall longitudinal extent of scaphoid and can be planned preoperatively using CT-scans. Surgeons treating these fractures should opt for a CT-based analysis regarding the screw direction and length and need to be familiar with the variations in scaphoid morphometry.
