451. Suture slippage in knotless suture anchors as a potential failure mechanism in rotator cuff repair
- Author
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Mazda Farshad, Karl Wieser, Kurt Ruffieux, Lazaros Vlachopoulos, Christian Gerber, Dominik C. Meyer, University of Zurich, and Wieser, Karl
- Subjects
medicine.medical_specialty ,Polymers ,Failure mechanism ,610 Medicine & health ,Weight-Bearing ,Rotator Cuff ,2732 Orthopedics and Sports Medicine ,Suture (anatomy) ,Suture Anchors ,Absorbable Implants ,Materials Testing ,medicine ,Animals ,Orthopedics and Sports Medicine ,Rotator cuff ,Suture anchors ,Orthodontics ,business.industry ,Suture Techniques ,Pullout strength ,Clamping ,Surgery ,Biomechanical Phenomena ,Equipment Failure Analysis ,Bovine bone ,medicine.anatomical_structure ,Metals ,Models, Animal ,10046 Balgrist University Hospital, Swiss Spinal Cord Injury Center ,Cattle ,Slippage ,business - Abstract
Purpose To quantify the strength of suture fixation of knotless suture anchors in relation to the anchors' pullout strength and to compare these results with the static friction between different sutures and anchor materials. Methods Suture slippage within the anchor and pullout strength of 4 different knotless suture anchor models were assessed in a bovine bone model. Furthermore, the peak force before onset of slippage of different sutures trapped between increasingly loaded 4-mm rods made of commonly used anchor material (polyetheretherketone, poly-L-lactide acid, metal) was assessed. Results In all but 1 of the tested anchors, there was a relevantly lower load needed for slippage of the sutures than to pull out the anchor from bone. The mean load to anchor pullout ranged between 156 and 269 N. The load to suture slippage ranged between 66 and 109 N. All sutures were better held between the metal rods (mean, 21; 95% confidence interval [CI], 19.2 to 23.3) than with polyetheretherketone rods (mean, 17; 95% CI, 15.7 to 18.1) or poly-L-lactide acid rods (mean, 18; 95% CI, 17.6 to 18.4). Conclusions In the case of suture anchors that hold the sutures by clamping, the hold of the suture in the anchor may be far lower than the pullout strength of the anchor from bone, because the sutures just slip out from the anchor through the clamping mechanism. This is well explained by the low static friction achieved between the tested sutures and the test rods made of anchor materials. Clinical Relevance The use of knotless suture anchors appears quick and easy to perform; however, most of the anchor systems could not even reach half of the anchor pullout strength from bone before suture slippage occurred.
- Published
- 2011