Does native glenoid anatomy predispose to shoulder instability? An MRI analysis.

Area of Science:

• Orthopedic Surgery
• Sports Medicine
• Radiology

Background:

• Glenohumeral instability in young patients may be linked to native anatomical features.
• Understanding sex-based differences in these anatomical risk factors is crucial for targeted prevention and treatment.

Purpose of the Study:

• To compare glenoid and humeral head dimensions between young patients with instability (without bone loss) and matched controls.
• To investigate potential sex-based differences in these anatomical measurements.

Main Methods:

• Magnetic resonance imaging (MRI) was used to measure glenoid and humeral dimensions in patients (<21 years) with instability and controls.
• Exclusion criteria included prior surgery, bony Bankart lesions, or bone loss.
• Calculated metrics included glenoid surface area and glenohumeral mismatch ratio.

Main Results:

• No overall differences in glenoid or humeral dimensions were found between instability patients and controls.
• However, males with instability exhibited a smaller glenoid width and surface area compared to male controls.
• Males with instability also showed a greater glenohumeral mismatch ratio.

Conclusions:

• Smaller glenoid dimensions and a proportionally smaller glenoid relative to humeral width are associated with instability in males.
• Bony glenohumeral morphology does not appear to be a significant risk factor for instability in females.
• Anatomical factors may influence shoulder instability risk differently in males and females.