Cadaveric biomechanical study using nine fresh-frozen upper extremities and a dynamic shoulder testing apparatus to quantify how five progressive rotator cuff tear configurations — from intact to global tear — affect the magnitude and direction of glenohumeral joint reaction forces during simulated scapular plane abduction.
When a patient with a known rotator cuff tear has disproportionate weakness and cannot actively elevate against gravity, suspect posterior extension into the infraspinatus — not just supraspinatus involvement.
This study quantifies why isolated supraspinatus tears are often functionally tolerated while tears crossing into the infraspinatus or subscapularis produce the profound instability and elevation loss you see clinically, and should heighten your urgency for repair of the transverse force couple.
Cadaveric biomechanical study using nine fresh-frozen upper extremities and a dynamic shoulder testing apparatus to quantify how five progressive rotator cuff tear configurations — from intact to global tear — affect the magnitude and direction of glenohumeral joint reaction forces during simulated scapular plane abduction.
When a patient with a known rotator cuff tear has disproportionate weakness and cannot actively elevate against gravity, suspect posterior extension into the infraspinatus — not just supraspinatus involvement.
This study quantifies why isolated supraspinatus tears are often functionally tolerated while tears crossing into the infraspinatus or subscapularis produce the profound instability and elevation loss you see clinically, and should heighten your urgency for repair of the transverse force couple.