Comparison of glenoid inclination angle using different clinical imaging modalities

Area of Science:

• Orthopedic surgery
• Radiology
• Biomedical engineering

Background:

• The β-angle is a clinical tool for analyzing glenoid inclination on shoulder anteroposterior (AP) radiographs.
• Accurate glenoid inclination measurement is crucial for surgical planning and outcomes.

Purpose of the Study:

• To compare the accuracy of β-angle measurements across different imaging modalities.
• To validate β-angle measurements against a 3-dimensional (3D) software tool.

Main Methods:

• The β-angle was measured on AP radiographs, unformatted 2D CT scans, and reformatted 2D CT scans in the scapular plane.
• Measurements were compared to glenoid inclination angles calculated by validated 3D software for 51 shoulders.

Main Results:

• Reformatted 2D CT scans yielded the most accurate β-angle measurements (mean difference of 1° vs. 3D).
• AP radiographs showed less accuracy (mean difference of 3°).
• Unformatted 2D CT scans were unreliable (mean difference of 10°).

Conclusions:

• 2D CT scans reformatted in the scapular plane provide the most accurate method for measuring glenoid inclination using the β-angle.
• AP radiographs offer less reliable β-angle measurements.
• Unformatted 2D CT scans are not suitable for determining glenoid inclination via the β-angle.