Background and aims: Large and massive rotator cuff tears (RCT) are associated with significant pain and disability and affect the position of the humeral head in the glenoid. The purpose of this study was to examine the accuracy of superior migration of the humeral head on plain radiographs using magnetic resonance imaging (MRI) as the gold standard. Methods:  This was a prospective diagnostic study. The superior subluxation of the humeral head was measured in two radiographic views. The validity indices examined the accuracy of acromiohumeral distance (AHD) of <6m and ≥6m in relation to MRI findings.  Results: 150 consecutive patients (mean age 59, SD 11, 57 females) were assessed at a tertiary shoulder centre. The AHD of <6m was highly specific in both views for muscle wasting (98%), presence of tear (98%), tear size (96-98%) and fatty infiltration in supraspinatus and infraspinatus muscles (93-96%). Absence of AHD of <6m was highly correlated with lack of advanced fatty infiltration (sensitivity values ranging from 91% to 100%). Sensitivity values were low for all other MRI findings ranging from15% to 56%. Conclusion: Superior migration of the humeral head with respect to glenoid is an important radiological sign that can be reliably measured in various views. The strong correlation between reduced AHD and advanced RC pathology in patients with painful and disabling rotator cuff tears assists with clinical decision-making for appropriate surgical intervention. In cases with a massive RCT, a reverse arthroplasty may be indicated as the repair is usually not feasible.

SUPERIOR GLENOHUMERAL SUBLUXATION IN PAINFUL AND MAJOR ROTATOR CUFF PATHOLOGY