A high re-rupture rate after the arthroscopic repair of rotator cuff with large and massive tear were recently reported on MRI study. The objective of this study was to investigate the effectiveness of the new suture technique biomechanically. 18 bovine infraspinatus tendons were repaired to the humerus with 2 suture techniques as follows: A; a dual-row suture technique with four Fastin anchors and tied by using SMC knot, B; knotless suture of the loop from the medially placed 2 Fastin anchors with use of 4 bioknotless anchors C, a pull-out transosseous suture of 8 threads from proximally placed 2 Fastin anchors. The breaking strength, failure mode during tensile testing and the stress distribution immediately after repair of the rotator cuff with these techniques using 3 finite element models were compared. The breaking strength was averaged to 310N in A, 283N in B and 368N in B, respectively. Although a stress concentration was seen around the medial anchor in A, no stress concentration was found inside of the tendon in B or C. A new suture technique could obtain almost the same strength and better stress distribution pattern compared with the dual-row technique.
