Editorial Commentary: Clinical Improvements of Superior Capsular Reconstruction Are Not Due to Maintained Dynamic Acromiohumeral Distance

Biomechanical data often help inform clinical decision-making in orthopaedic surgery. However, there are times when the biomechanical data and clinical data do not align. This is seen in cases of statistical but clinically irrelevant differences. This is also seen at times in cases of demonstrated clinical improvements with a poorly understood mechanism. Superior capsular reconstruction has gained significant traction since the original description in 2012. It has taken a central role in the armamentarium of treatment options of irreparable rotator cuff tears. There is robust published literature on the time zero biomechanics of superior capsular reconstruction and its stabilizing effects on the glenohumeral joint, especially with regards to superior migration of the humeral head. There also is demonstrated good early patient-reported outcomes with superior capsular reconstruction. However, the cause and effect may not be as simple as the biomechanical studies may suggest, and the underlying mechanism of why the superior capsular reconstruction appears to improve early outcomes remains poorly understood. These mechanisms are important to understand in order to inform technique changes and improvements and help us optimize treatment of the patient with an irreparable rotator cuff tear.