Computed Tomography-Based Humeral Templating for Uncemented Elbow Arthroplasty

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Radiology

Background:

• Intramedullary (IM) screw fixation is crucial for novel uncemented elbow arthroplasty.
• Variable humeral morphology necessitates a range of screw sizes.
• Accurate IM screw sizing is essential for successful arthroplasty outcomes.

Purpose of the Study:

• To utilize computed tomography (CT) for precise intramedullary (IM) screw sizing in the distal humerus.
• To validate CT-based templating by implanting screws into three-dimensional (3D) printed humerus models.
• To characterize distal humerus anatomy relevant to IM screw fixation for elbow arthroplasty.

Main Methods:

• CT scans of 30 humeri were analyzed to measure distal IM canal diameters at specific locations.
• Screw sizes were templated based on canal measurements.
• Interrater and intrarater reliability of measurements were assessed.
• IM screws were implanted into 3D printed humerus models (n=5) for validation.

Main Results:

• CT-based templating successfully identified appropriate IM screw length and diameter combinations for all patients.
• Canal diameter measurements were reliable and correlated with patient age.
• Screws implanted into 3D models demonstrated a secure fit, validating the CT templating method.
• Mechanical and radiographic evidence confirmed the secure fit of implanted screws.

Conclusions:

• CT templating provides a reliable method for predicting optimal IM screw size for distal humerus fixation.
• Validation using 3D printed models confirms the accuracy of CT-based templating.
• A comprehensive range of IM screw lengths and diameters is vital for this novel elbow arthroplasty.
• This approach enhances surgical planning and improves outcomes for uncemented elbow arthroplasty.