Cyclic and Load-to-Failure Properties of All-Suture Anchors in Human Cadaveric Shoulder Greater Tuberosities.

PURPOSE The purpose of this study was to evaluate the cyclic displacement, stiffness and ultimate load to failure of three all-suture anchors in human cadaveric greater tuberosities. METHODS Three all-suture anchors indicated for rotator cuff repair were tested in 14 matched pairs of human cadaver fresh-frozen humeri. Anchors were inserted at three locations from anterior to posterior along the greater tuberosity and placed 5 mm from the articular margin. The constructs were cycled from 10 to 60 N at 1 Hz for 200 cycles. The anchors that survived cycling were then subjected to a single pull to failure test. A Kruskal-Wallis 1-way analysis of variance on ranks was performed to compare the displacement, stiffness and ultimate load to failure of the different anchors tested. RESULTS One matched pair was excluded because of poor bone quality. Therefore, 13 matched pairs were included in the study. After 20, 100, and 200 cycles there was no difference in median displacement between the anchors tested (p= 0.23, p=0.21, p=0.18, respectively). The median ultimate load-to-failure between the Iconix (295.2 N, 95% confidence interval (CI) [125-762.2]), JuggerKnot (287.6 N 95% CI [152.9-584.4]) and Q-fix (333.3 N, 95% CI [165.0-671.9]) showed no statistically significant difference (p=0.58). After 20, 100, and 200 cycles there was no difference in median stiffness between the anchors tested (p=0.41, p=0.19, p=0.26 respectively). Displacement greater than 5 mm occurred in 0 Iconix anchors (0%), 1 JuggerKnot anchor (3.64%) and 2 Q-fix anchors (7.69%). One JuggerKnot anchor failed by anchor pullout during cyclic loading. CONCLUSION When tested in human cadaveric humeral greater tuberosities three all-suture anchors, the 2.9-mm JuggerKnot, the 2.8-mm Q-fix, and the 2.3-mm Iconix, showed no significant differences in median displacement or stiffness after 20, 100 or 200 cycles or in median ultimate load to failure. While not statistically significant, the Iconix was the only anchor tested to have no failures while the JuggerKnot had both a clinical and catastrophic failure and the Q-fix had 2 clinical failures. CLINICAL RELEVANCE All-suture anchors vary in their design and deployment mechanism, which may alter their strength and performance. In deciding which anchors to utilize, surgeons must be aware of their inherent differences and propensity to displace or fail.