Variability in total shoulder arthroplasty planning software compared to a control CT-derived 3D printed scapula

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Radiology

Background:

• Total shoulder arthroplasty relies on 3D preoperative planning software.
• Existing techniques include Landmark-based and Automated (best-fit sphere) methods.
• Comparison against computed tomography-derived 3D printed scapula is crucial for accuracy.

Purpose of the Study:

• To compare glenoid measurements derived from Landmark and Automated 3D planning software.
• To evaluate the accuracy of these techniques against a control 3D printed scapula.
• To identify potential discrepancies in glenoid version and inclination measurements.

Main Methods:

• Computed tomography scans of 20 osteoarthritic shoulders were analyzed.
• Glenoid version and inclination were measured using both Landmark and Automated 3D planning software.
• Measurements were compared to a 3D printed scapula derived from the patient's CT scan.

Main Results:

• Significant variability in glenoid version was observed (p=0.007).
• 65% of Automated and 45% of Landmark cases showed a 5° or greater difference in version or inclination.
• Glenoid version: Scapula (13.0°), Automated (15.0°), Landmark (12.2°). Inclination: Scapula (5.4°), Automated (6.1°), Landmark (6.2°).

Conclusions:

• Both 3D planning software techniques exhibit a high percentage of discrepancies in glenoid inclination and version.
• Variability exists regardless of the software technique employed.
• Surgeons should be aware of these potential inaccuracies during preoperative planning for total shoulder arthroplasty.