ePoster #311 - ISHA Annual Scientific Meeting 2016

Cyclic and Load to Failure Properties of All-Suture Anchors in Synthetic Acetabular Cancellous Bone

Nathan Douglass, MD, Redwood City, CA UNITED STATES
Anthony Behn, MS, Stanford, CA UNITED STATES
Marc R. Safran, MD, Redwood City, CA UNITED STATES

Stanford University Medical Center, Stanford, California, UNITED STATES

FDA Status Not Applicable

Summary: Commercially available all-suture anchors vary widely in performance in high-density synthetic acetabular bone compared to a control PEEK anchor

Abstract:
INTRODUCTION: This study evaluated the cyclic displacement, maximum load to failure, and failure mode of all commercially available all-suture anchors (ASA) indicated for hip labral repair. Anchors were tested in various densities of sawbones cancellous bone substitute simulating the range of bone properties found in the acetabulum. This study tested the theory that the deployment of all-suture anchors may be inhibited in higher density bone.
METHODS: Anchors tested included the Bioraptor 2.3 PK, Suturefix Ultra 1.7, JuggerKnot 1.45 (#1 and #2 suture versions), JuggerKnot 2.9, Y-Knot Flex 1.3 and 1.8, Iconix 1, 2, 25, and 3, and Q-Fix 1.8. The Bioraptor 2.3 PEEK anchor served as a control. Between 7 and 11 anchors were tested in both 20 pcf and 30 pcf test blocks, to simulate a range of acetabular bone densities. Following a 40 N simulated deployment force, anchors were cyclically loaded from 10-50 N at 0.5 Hz for 200 cycles, followed by 10-100 N for 200 cycles. Surviving specimens were pulled to failure at 10 mm/s.
RESULTS: Anchors showed increased or no difference in maximum load to failure in 30 pcf versus 20 pcf test blocks. Performance compared to a PEEK control varied widely. Failure occurred primarily by anchor pullout, except the Q-Fix 1.8 which failed exclusively by suture breakage at higher densities. The Q-Fix 1.8 had nearly zero (0.1 ± 0.2 mm) post-cyclic displacement in both test block densities. All other anchors including the control exhibited at least 2.8 mm and 0.6 mm post-cyclic displacement in 20 pcf and 30 pcf test blocks, respectively. The Iconix 25 exhibited the highest maximum load to failure in both 30 pcf (307.1 ± 81.7 N) and 20 pcf (196.0 ± 15.9 N) bone blocks.
CONCLUSIONS: The cyclic displacement and maximum load of commercially available all-suture anchors varies widely depending on the anchor design and bone density. Most anchors fail by suture anchor pullout in test blocks replicating acetabular cancellous bone. All-suture anchors have better fixation in higher density bone. All suture anchors have comparable biomechanical properties with a standard suture anchor in simulated bone of different densities.