Possibility of diagnosing rotator cuff tears in areas with scarce medical resources: Can non-standard anteroposterior radiographs accurately predict rotator cuff tears?

A retrospective study was conducted on patients who reported shoulder discomfort and completed both shoulder joint MRI and scapular anteroposterior radiographic examinations at the *** Hospital between January 2017 and April 2023. After the removal of confounding factors, the 3.0T MRI was employed as the benchmark to segregate the patients into rotator cuff tear and control groups. Standard anteroposterior radiography was discerned based on earlier study classification criteria. Independent measurements of acromiohumeral interval, upward migration index, acromial index, critical shoulder angle, and double-circle radius ratio were taken from the radiograph films by three evaluators. The Intraclass Correlation Coefficient was used to assess the consistency between the measurements. The Receiver Operating Characteristic curves were utilised to determine the predictive power of each method for rotator cuff tears in non-standard anteroposterior radiographs. Three orthopedic doctors, boasting substantial diagnostic acumen and clinical experience, independently evaluated the AHI, UMI, AI, CSA, and DRR through the use of Digimizer software subsequent to rigorous training. All data, including AHI measurements taken in millimeters, were recorded to two decimal places to enhance precision. The magnification range for the image measurement was set between 500% and 2000% to further advance accuracy.  The schematic diagram of each measurement method. AHI: The minimum distance from the subcortical surface of the acromion to the humeral head . CSA: The angle formed by line connecting the upper and lower rims of the glenoid, and the line extending from the lower glenoid to the acromion’s outside edge. AI: The ratio of two distances- the rim of the glenoid to the acromion (a), and from the rim of the glenoid to the outer edge of the humeral head (b) . UMI: The division of the distance from the geometric center of the humeral hea isd to the subcortical surface of the acromion by the radius of the humeral head . DRR:The ratio between the outer circle radius R and the inner circle radius r, where the inner circle is the optimal fit for the humeral head, and the outer circle is a concentric circle intersecting Greater Tubercle of Humerus.