Sutures and suture anchors - Update 2006

Purpose: To evaluate recently introduced sutures and suture anchors for single pull load to failure strength and failure mode. Methods: Suture anchors were tested in fresh porcine metaphyseal cortex and cancellous troughs with the use of an established protocol. An Instron machine applied tensile loads parallel to the axis of insertion at a rate of 12.5 mm/sec until failure, and mean anchor failure strengths were calculated. The mode of failure (anchor pull-out, suture eyelet cut-out, or suture failure) was recorded. Anchors tested included the BioRaptor 2.9, BioZip, Super Revo, Impact, Allograft cortical anchor, SpiraLok, Herculon, AxyaLoop titanium anchors 3, 5, and 6.5 mm, AxyaLoop bioabsorbable anchors 3, 5, and 6.5, ParaFix titanium anchors 3, 5, and 6.5, ParaSorb BioAnchors 3, 5.5, and 6.5, and Bio-Corkscrew FT. Sutures were also tested through an established protocol for load to failure. Sutures tested consisted of Orthocord, Ultrabraid (White and CoBraid), ForceFiber, Hi-Fi, MagnumWire, and Maxbraid Polyethylene Plus. Results: Mean failure loads were as follows: BioRaptor 238 N, BioZip 366 N, double-loaded Super Revo 486 N, triple-loaded Super Revo 362 N, Impact 202 N, Allograft cortical anchor 240 N, SpiraLok 289 N, Herculon 819 N, AxyaLoop titanium anchors 3.0 (335 N), 5.0 (485 N), and 6.5 mm (465 N), AxyaLoop bioabsorbable anchors 3 (143 N), 5 (395 N), and 6.5 (369 N), ParaFix titanium anchors 3 (335 N), 5 (485 N), and 6.5 (465 N), ParaSorb BioAnchors 3 (143 N), 5.5 (395 N), and 6.5 (369 N), and Bio-Corkscrew FT (260 N). The sutures all broke at the mid point of their tested strands away from the grips. Mean suture strength for No. 2 Orthocord was 92 N; for No. 2 Ultrabraid CoBraid and White, strengths were 265 N and 280 N, respectively; strength for No. 2 Force Fiber was 289 N, for No. 2 Hi-Fi 250 N, for No. 2 MagnumWire 303 N, and for No. 2 Maxbraid Polyethylene Plus 256 N. Conclusions: Newer suture products showed significant improvements in load to failure values when compared with braided polyester sutures. Higher load to failure values continue to be seen in metal versus biodegradable anchors and in screw-type versus nonscrew designs. Clinical Relevance: Surgeons who prefer stronger sutures now have several high-strength suture options from which to choose. Most of the new anchors tested performed very well.