Purpose: Recent advances in arthroscopic shoulder surgery has expanded the options available to surgeons repairing rotator cuff tears. There are now a variety of suture techniques that arthroscopists can use to fix tears but limited data on which might work best, particularly for double row techniques. The objective of this study was to compare the initial cyclic loading and load to failure properties of two arthroscopic double row fixation with that of the open double row technique.

Method: Thirty sheep shoulders were harvested and the infraspinatus tendons dissected free from all surrounding muscles and osseous attachments. Three double row stitch configurations (arthroscopic standard, arthroscopic mason-allen, open mason-allen) were performed and tested. The shoulders were then secured in a material testings machine and cyclically loaded between 5 and 100 N at 0.20 Hz for 10 cycles and then loaded to failure under displacement control at 1 mm/sec. Stiffness and ultimate load were measured and compared. The failure type, either through suture or anchor pull out, was also recorded.

Results: None of the specimens failed under cyclic loading. The ultimate load to failure was significantly higher for the open double row and the arthroscopic mason-allen compared to the standard double row technique. No significant differences in stiffness were found among the stitches. All failures occurred at the suture-tendon junction.

Conclusion: In this in vitro cadaver sheep study, the arthroscopic mason-allen and open mason-allen techniques had a significantly higher ultimate load to failure than the standard double row technique. Stitching methods that strengthen the tendon-suture interface can improve the strength of double row rotator cuff repairs.