Diagnosis of Engaging Bipolar Bone Defects in the Shoulder Using 2-Dimensional Computed Tomography: A Cadaveric Study

Area of Science:

• Orthopedics
• Sports Medicine
• Radiology

Background:

• Bipolar bone loss (glenoid and humeral) cumulatively impacts shoulder instability.
• Engagement of bone defects in specific positions can lead to stabilization procedure failure.
• Accurate assessment of engaging lesions remains a challenge.

Purpose of the Study:

• To evaluate the interaction between humeral and glenoid bone defects on shoulder engagement.
• To assess CT in abduction and external rotation (ABER) for predicting engagement.
• To evaluate glenoid lesion width and intact anterior articular angle (IAAA) for engagement prediction.

Main Methods:

• Created 45 bipolar defect combinations in 12 cadaveric shoulders.
• Assessed defects using CT in neutral and ABER positions.
• Measured glenoid defect width and IAAA on 2D reformats; compared with glenoid track method.

Main Results:

• The glenoid track method identified 53% of engaging defects.
• ABER CT accurately predicted engagement in 96% of cases (92% sensitivity, 100% specificity).
• Glenoid defect width and IAAA model achieved 87% accuracy (92% sensitivity, 81% specificity).

Conclusions:

• ABER CT and 2D measurements (glenoid width, IAAA) accurately identify engaging bipolar bone defects.
• These methods aid surgical planning for shoulder stabilization with bipolar defects.
• Improved prediction of engagement enhances outcomes for shoulder instability surgery.