[Stress on the rotator cuff sutures in relation to joint position]

In a vitro study we evaluated the influence of surgical technique on the postoperative tension of the supraspinatus tendon in rotator cuff ruptures. In ten shoulder specimens Hall-Effect Strain Gauge (HEST) were implanted in the supraspinatus tendon close to the insertion at the humerus. We documented the tension in specimens with intact rotator cuff as well as after reconstruction of small and large tears in different joint positions. In the specimens with an intact rotator cuff there was almost no tension registered. Only in adduction with external rotation and flexion we found slightly increased values. After reconstruction we found the highest tension in adduction, flexion, and external rotation of the humerus. Release of the coracohumeral ligament resulted in a decrease of tension in flexion and external rotation. Whereas in extension coracohumeral ligament release had no influence on the tension of the tendon. However, after complete capsule release the tension in extension also decreased.

If mobilisation in cases of rotator cuff reconstruction is necessary we recommend first release of the coracohumeral ligament in small and moderate tears. In major tears a complete capsule release is necessary. During physical therapy in the early postoperative course, flexion in the adducted and externally rotated arm should be avoided.