title: Cyclic and Load to Failure Properties of All-Suture Anchors in Synthetic Acetabular and Glenoid Cancellous Bone.
abstract: OBJECTIVE
  To evaluate the cyclic displacement, maximum load to failure, and failure mode of multiple all-suture anchors (ASAs) in 2 different densities of sawbones cancellous bone substitute.
  
  
  METHODS
  Anchors tested included the Suturefix Ultra 1.7 mm, JuggerKnot 1.45 mm (No. 1 and No. 2 MaxBraid) and 2.9 mm, Y-Knot Flex 1.3 mm and 1.8 mm, Iconix 1, 2, 25, and 3, Q-Fix 1.8 mm, and Bioraptor 2.3 PK. The Bioraptor served as a non-all-suture-based control. Seven to eleven anchors were tested in both 20 and 30 pounds per cubic foot (pcf) test blocks that were chosen to simulate glenoid and acetabular cancellous bone, respectively. After a 40 N deployment force, anchors were cyclically loaded at 0.5 Hz from 10 to 50 N and then 10 to 100 N for 200 cycles each. Surviving specimens were pulled to failure at 10 mm/s. Displacement, stiffness, maximum load, and failure mode were recorded. Welch t-tests and Welch analysis of variance with Games-Howell post hoc tests were used for statistical analysis.
  
  
  RESULTS
  In higher density blocks, 11 of 12 anchors had significantly (P < .05) higher maximum loads to failure, and 8 anchors showed significantly lower post-cyclic displacement. The Q-Fix 1.8 displayed the lowest post-cyclic displacement in both densities (0.1 ± 0.2 mm, mean ± standard deviation, in both densities). All other groups exhibited at least 2.8 mm and 0.6 mm post-cyclic displacement in 20 and 30 pcf, respectively. The Bioraptor did not survive cyclic testing in 20 pcf and had 0.6 ± 0.3 mm post-cyclic displacement in 30 pcf.
  
  
  CONCLUSIONS
  ASAs show better fixation in higher density synthetic bone. The cyclic displacement and maximum load of ASAs vary widely depending on anchor design and bone density. Most anchors fail by suture anchor pullout. In general, the Bioraptor 2.3 PK outperformed ASAs in higher density test blocks with mixed results in lower density test blocks.
  
  
  CONCLUSIONS
  ASAs show mixed results compared with a traditional suture anchor. They perform better in higher density bone substitute.
authors.affiliation: Department of Orthopaedic Surgery, Stanford University, Redwood City, California, U.S.A.
authors.forename: Nathan P
authors.initials: NP
authors.lastname: Douglass
authors.affiliation: Department of Orthopaedic Surgery, Stanford University, Redwood City, California, U.S.A.
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Behn
authors.affiliation: Department of Orthopaedic Surgery, Stanford University, Redwood City, California, U.S.A.. Electronic address: msafran@stanford.edu.
authors.forename: Marc R
authors.initials: MR
authors.lastname: Safran
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D018786:Bone Substitutes; D002102:Cadaver; D000071556:Cancellous Bone / Q000601:surgery; D005260:Female; D061165:Glenoid Cavity / Q000601:surgery*; D006801:Humans; D008297:Male; D053441:Suture Anchors; D013536:Suture Techniques
chemical_list: D018786:Bone Substitutes