Inferior Glenohumeral Vertical Distance: A Novel Radiographic Marker Better Suited For Detection Of Rotator Cuff Tears Involving The Infraspinatus Tendon

Background: Non-pathological radiological factors can decrease acromiohumeral distance (AH), and increase the false positive rate of radiographic signs of rotator cuff tears (RCT). Our goal is to evaluate the association between the radiographically determined inferior glenohumeral vertical distance (IGH) and RCT involving the infraspinatus (IS) tendon and compare the sensitivity and specificity of AH and IGH for RCT involving the IS tendon. Methods: 140 patients with MRI-proven full-thickness rotator cuff tears were included after they met the inclusion and exclusion criteria. Patients were divided into two groups, Group A: patients with RCT involving full or partial IS tears, and Group B: RCT not involving IS. Shoulders MRIs were evaluated by board-certified musculoskeletal radiologists. Radiographs were analyzed and blinded to MRI findings. IGH was determined by measuring the vertical distance from the anatomical neck to the inferior glenoid level in an anteroposterior (AP) view; a distance of more than 2mm was considered positive. AH was assessed by measuring vertical intervals between the inferior border of the acromion process and the humeral head in (AP) view; a distance less than 7 mm was considered positive. The correlation between increased IGH and the presence of IS involvement was assessed. Sensitivity, specificity, PPV, and NPV were compared between IGH and AH in assessing IS tendon tear. Further subgroup analysis of Group A separating full and partial IS tears was performed. Results: Group A included 89 patients and Group B involved 51 patients. A strong association was found between IGH and rotator cuff tears involving the infraspinatus tendon (p < 0.001). IGH was found to have increased sensitivity, PPV, and NPV (66%, 92%, and 60%, respectively) compared to AH (20%, 85%, and 40% respectively). The specificity of both was comparable (90% for IGH and 94% for AH). Subgroup analysis included 54 patients with full-thickness infraspinatus tears and 35 patients with partial infraspinatus tears. No statistically significant difference between these two groups in terms of IGHVD was found. Conclusion: There is a strong association between IGH and RCT involving infraspinatus and is more sensitive than AH.