Fluoroscopic evaluation for subtle shoulder instability

Area of Science:

• Orthopedic Surgery
• Diagnostic Imaging

Background:

• Shoulder instability is a common cause of shoulder pain and dysfunction.
• Accurate diagnosis is crucial for effective treatment, but subtle instability can be challenging to detect.

Purpose of the Study:

• To establish normal glenohumeral translation ranges using fluoroscopic stress testing.
• To evaluate the diagnostic accuracy of this technique in identifying shoulder instability.
• To develop a quantitative method for assessing shoulder stability.

Main Methods:

• Fluoroscopic stress testing under general anesthesia in 50 patients with unilateral shoulder symptoms.
• Measurement of anterior and posterior humeral head translation relative to the glenoid in a neutral position.
• Comparison with the asymptomatic contralateral shoulder as a control.

Main Results:

• Normal anterior translation up to 14% and posterior translation up to 37% were defined.
• The technique demonstrated high sensitivity (93%) and specificity (100%) in identifying instability.
• A discriminant function analysis generated a 10% difference score, reducing interobserver variability.

Conclusions:

• Fluoroscopic stress testing provides valuable quantitative data for diagnosing shoulder instability.
• This method can accurately identify and predict subtle instability patterns, especially in recalcitrant cases.
• The established normal translation ranges serve as a reliable reference for clinical assessment.