Preoperative planning for accurate glenoid component positioning in reverse shoulder arthroplasty

Area of Science:

• Orthopedic surgery
• Biomedical engineering
• Radiology

Background:

• Accurate glenoid component positioning is critical in reverse shoulder arthroplasty (RSA).
• Patient-specific instrumentation (PSI) relies on precise preoperative planning.
• Current virtual planning methods may not fully utilize available anatomical references.

Purpose of the Study:

• To compare the accuracy of glenoid component positioning in virtual RSA planning.
• To evaluate the impact of visualizing only the glenoid versus the entire scapula on accuracy.
• To assess the reduction in glenoid vault perforation risk with different visualization methods.

Main Methods:

• 3D virtual models were created from CT scans of 30 arthritic shoulders.
• Surgeons virtually placed glenoid components simulating 'blind 3D' (glenoid only) and 'visible 3D' (entire scapula) scenarios.
• Accuracy was assessed by measuring correction of native glenoid version and tilt, and incidence of glenoid vault perforation.

Main Results:

• 'Blind 3D' surgery resulted in mean version of +1.4° and tilt of +7.6°, with 17 perforations.
• 'Visible 3D' surgery yielded mean version of +0.3° and tilt of +0.1°, with 6 perforations.
• The 'visible 3D' approach demonstrated significantly higher accuracy (P<0.05).

Conclusions:

• Utilizing the entire scapula as a reference in 3D virtual planning enhances glenoid component positioning accuracy.
• This comprehensive visualization approach reduces the likelihood of glenoid vault perforation.
• Preoperative 3D CT planning, potentially augmented by PSI, is crucial for optimizing RSA outcomes.