Diagnostic Ultrasound in the Evaluation of Stiff Shoulder: Association of Axillary Recess Thickness with Standard Clinical Measures.

ABSTRACT

OBJECTIVES: Stiff shoulder, including primary and secondary types, poses diagnostic challenges due to vague definitions and criteria. This study evaluates the diagnostic potential of ultrasound-measured axillary recess (AR) thickness in shoulder stiffness. DESIGNS In this cross-sectional study, 35 patients with unilateral shoulder stiffness were assessed. AR thickness was measured using high-resolution ultrasound. Parameters like passive range of motion (PROM), Numerical Rating Scale (NRS), and Constant-Murley (CM) score were evaluated to find correlations with AR thickness. RESULTS: The average age was 50.7 years, and mean BMI was 22.7. AR thickness in stiff shoulders (average 3.19 mm) was significantly higher than in unaffected shoulders (average 1.93 mm, p < 0.001). A cutoff of 3.0 mm for AR thickness yielded 73.3% sensitivity and 84.6% specificity for primary stiffness; 2.6 mm cutoff resulted in 57.9% sensitivity and 88.2% specificity for secondary stiffness. Significant correlations were found between AR thickness and PROM, especially in shoulder external rotation and extension. CONCLUSION: AR thickness measured by ultrasound might serve as a valuable diagnostic and evaluation parameter in shoulder stiffness.