Superior Migration of the Humeral Head in Chronic Rotator Cuff Disease: A Narrative Review of Pathomechanisms, Diagnosis, and Treatment.

Superior migration of the humeral head (HH) refers to pathological cranial displacement of the HH resulting from chronic rotator cuff (RC) dysfunction and loss of dynamic glenohumeral stabilization. This disturbance is reflected by a reduction of the acromiohumeral interval (AHI), defined as the distance between the inferior border of the acromion and the uppermost part of the HH. Reduced AHI is associated with massive irreparable rotator cuff tears (RCTs), rotator cuff arthropathy (RCA), and inferior surgical outcomes. This narrative review aims to summarize the pathomechanisms, diagnostic value, and treatment implications of superior HH migration in chronic and massive RCTs. Particular emphasis is placed on the clinical relevance of AHI as a marker of disease severity, fatty infiltration, treatment outcomes, and retear risk. While procedures such as partial repair, superior capsular reconstruction (SCR), and lower trapezius transfer (LTT) may improve AHI and shoulder function in selected patients, reverse shoulder arthroplasty (RSA) remains the most reliable option in advanced disease. Although AHI is a simple, inexpensive, and easily accessible marker, it should not serve as a sole criterion for surgical decision-making. Treatment should be tailored to the patient, depending on age, activity demands, and the severity of glenohumeral joint (GHJ) osteoarthritis (OA).