Diagnostic accuracy of Neer's impingement test for subacromial shoulder impingement

Subacromial impingement syndrome (SIS) is one of the most common causes of shoulder pain, encompassing a spectrum of conditions ranging from bursitis to partial or complete rotator cuff tears. The Neer's impingement test is frequently used for clinical diagnosis, yet its accuracy remains debated. This study aims to evaluate the sensitivity, specificity, Positive predictive value (PPV), Negative predictive value (NPV), and diagnostic accuracy of Neer's test against Magnetic resonance imaging (MRI) as the gold standard.

A prospective study was conducted on 500 shoulders at a tertiary care centre. Patients presenting with unilateral or bilateral shoulder pain of at least three weeks duration underwent clinical evaluation using Neer's sign and Neer's test. Those with a positive Neer's sign were included and underwent subacromial lignocaine injection, followed by reassessment. All patients underwent MRI, and the results were compared. Diagnostic parameters including sensitivity, specificity, PPV, NPV, and diagnostic accuracy were calculated.

The study population had a mean age of 46.3 years with a male-to-female ratio of 2:1. MRI confirmed SIS in 81% of cases. Neer's test demonstrated a sensitivity of 79.0%, specificity of 63.2%, PPV of 90.1%, NPV of 41.4%, and diagnostic accuracy of 76.0%. Diagnostic accuracy was higher in rotator cuff pathologies (81.6%) compared to subacromial bursitis (70.4%). The test showed greater sensitivity (90%) for partial supraspinatus tears, but lower specificity.

Neer's test is a reliable, sensitive tool for diagnosing SIS, particularly in partial rotator cuff tears. However, its specificity remains moderate, warranting cautious interpretation alongside imaging.