Differences in Measurement of Glenoid Morphology Between Radiographs and Computed Tomography

Area of Science:

• Orthopedic surgery
• Radiology
• Biomedical engineering

Background:

• Preoperative planning and glenoid deformity assessment are crucial for successful reverse shoulder arthroplasty (RSA).
• Shoulder β and RSA angles are valuable metrics for RSA preoperative planning.

Purpose of the Study:

• To compare glenoid markers (β and RSA angles, bony resection depth) between plain radiographs and CT scans.
• To introduce and evaluate the inferior glenoid bony resection depth (BRD) for neutral baseplate placement.

Main Methods:

• A cohort study included 41 patients with both shoulder radiographs and CT scans.
• Measurements of β angle, RSA angle, and BRD were performed using both imaging modalities.
• Subgroup analysis examined differences between male and female patients.

Main Results:

• Plain radiographs showed a greater mean β angle (78.8° vs 76.9°) and average resection depth (7.32 mm vs 5.86 mm) compared to CT scans.
• Men exhibited a higher average β angle (81.6°) than women (75.8°).

Conclusions:

• Plain radiographs may overestimate the shoulder β angle and the required inferior glenoid bony resection.
• Overestimation of resection depth could lead to glenoid overresection and potential implant subsidence.
• Patient sex may influence glenoid inclination, suggesting sex-specific considerations in RSA planning.