The present research plan focused on a new intraoperative (arthroscopic) determinable parameter ("repair tension" on footprint in 0° and 40° abduction) to determine the risk of recurrence after tendon repair in rotator cuff tears, which are pre- and intraoperative defined as "reparable". Therefore, the tension of the repaired tendon is measured intraoperative with a spring balance (newtonmeter) and correlated with the postoperative retear-rate.