The Hamada classification divides the x-ray features of massive rotator cuff tears into five grades. Subsequently, Walch subdivided grade 4 into two subtypes 1,2.
Classification
Hamada classification with Walch modification of rotator cuff tear arthropathy 1,3:
grade 1: acromiohumeral interval ≥6 mm; normal glenohumeral joint
grade 2: acromiohumeral interval ≤5 mm; normal glenohumeral joint
grade 3: acromiohumeral interval ≤5 mm, with acetabulization of acromion; normal glenohumeral joint
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grade 4
grade 4a: glenohumeral osteoarthritis without acetabulization, acromiohumeral interval <7 mm
grade 4b: glenohumeral osteoarthritis with acetabulization, acromiohumeral interval ≤5 mm
grade 5: humeral head subchondral collapse characteristic of rotator cuff tear arthropathy
History and etymology
Hamada et al. first described radiographic findings of massive rotator cuff tears in 1990 1,2. In 2005, Walch divided the Hamada grade 4 classification into two subtypes for patients who had glenohumeral narrowing without acromial acetabulization 3.