Computerised Tomographic Analysis of Differences in Scaphoid Trabecular Density in the Intact Bone.

Area of Science:

• Orthopedic surgery
• Bone biomechanics
• Radiology

Background:

• Percutaneous screw fixation is a standard treatment for nondisplaced or scaphoid waist fractures.
• Screw positioning in regions of high trabecular bone density enhances fracture stability and promotes bone healing.
• Understanding scaphoid bone density variations is crucial for optimizing screw placement techniques.

Purpose of the Study:

• To compare the bone density across six distinct segments of the intact scaphoid bone.
• To identify optimal anatomical locations for screw insertion to maximize fracture healing.
• To guide surgical approaches for percutaneous screw placement in scaphoid fractures.

Main Methods:

• Utilized the 3D Quantitative Imaging (3DQI) Platform to analyze 214 intact scaphoid bone scans.
• Divided the scaphoid into proximal, middle, and distal regions, with further segmentation into radial and ulnar aspects.
• Measured bone density in Hounsfield units (HU) and statistically compared segment densities using a mixed-effects model.

Main Results:

• The proximal pole exhibited the highest bone density (proximal radial: 551 ± 115 HU; proximal ulnar: 546 ± 116 HU).
• Bone density decreased progressively from the proximal to the middle and distal poles.
• Proximal scaphoid segments were significantly denser than middle and distal segments.

Conclusions:

• For retrograde screw placement, initiating from a more ulnar aspect of the distal pole maximizes engagement with dense trabecular bone.
• The proximal pole offers uniform density, allowing screw placement flexibility based on the fracture plane for antegrade fixation.
• Prioritizing the ulnar segment of the distal pole, when feasible, is recommended for enhanced stability in scaphoid fracture treatment.