The number of loaded sutures alter the suture-holding strength in different knotless suture anchors: a biomechanical study.

Abstract Background Due to advances in arthroscopic rotator cuff repair, a knotless suture anchor is expected to hold more than two suture limbs. The objective of this study is to investigate whether when employing different fixation mechanisms, the suture-holding strength of knotless anchors are altered by the number of loaded sutures. Methods Three types of knotless anchors (spiral core clamping, winged clamping, and spooling) were tested, with each anchor double-loaded or quadruple-loaded. Cyclic loading was applied, followed by a tensile load until failure. Clinical failure load (CFL) was defined by 3mm slippage, and ultimate failure load (UFL) was defined as a sharp deviation in the linear load-versus-displacement curve. A two-way ANOVA was performed to examine the effects of suture anchors and suture number. Results The two-way ANOVA showed significant interaction between the type of suture anchor and the number of sutures (p Conclusions The number of loaded sutures does affect the suture-holding strength of knotless suture anchors, and anchors with different fixation mechanisms are affected differently.