Suture anchors, properties versus material and design: a biomechanical study in ovine model

The aim of our work was to compare the performance of suture anchors with various material and design that could be used in shoulder surgery. Three metallic and three bioabsorbable anchors mounted with stainless steel wire were tested. Their load to failure and mode of failure was determined in ex vivo ovine glenoids using Materials Testing Machine and attached load cell. Tensile load was applied at a rate of 60 mm/min, while load and displacement were recorded at a sampling rate of 100 Hz. Load to failure and failure mode was recorded. The mean load to failure for screw-type metallic anchors was Arthrex Fastak 678.3 N and Smith+Nephew Ti 3.5 499.7 N. Mitek GII (cylindrical with arcs) had a load to failure of 86.8 N. All bioabsorbable anchors exhibited lower load to failure comparing to screw-type metallic ones ( P = 0.007), which was not statistically different between each other ( P = 0.056): Arthrex BioFastak: 179.5 N; Mitek Panalok: 136.0 N; Smith+Nephew Bioraptor: 258.8 N. Metallic or bioabsorbable anchors had 30% eyelet failure (5/15 and 4/13, respectively). Our results suggest that metallic anchors have a better load to failure than bioabsorbable ones. Often the suture anchors’ weak point is their eyelet and needs further design improvement.