Influence of suture material on the biomechanical behavior of suture-tendon specimens: A controlled study in bovine rotator cuff

Background: Despite technical advances in rotator cuff surgery, recurrent or persistent defects in the repaired tendon continue to occur. Improved strength of sutures and suture anchors has resulted in the most common site of failure being the suture-tendon interface. Hypothesis: The type of suture material used has a significant effect on the biomechanics of the suture-tendon interface. Study Design: Controlled laboratory study. Methods: Thirty-two bovine infraspinatus specimens were randomly assigned to simple suture fixation using No. 2 Fiberwire, Ultrabraid, Orthocord, or Ethibond. Each specimen was subjected to cyclic testing from 5 to 30 N for 30 cycles, followed by load-to-failure testing. Results: Cyclic testing revealed significantly greater elongation with Ultrabraid, whereas peak-to-peak displacements were lowest for Fiberwire and greatest for Orthocord. Load-to-failure testing revealed no significant differences between any suture material for ultimate tensile load. Fiberwire and Orthocord repairs had the highest stiffness. The most common failure mode during load-to-failure testing was suture breakage in Ethibond specimens and suture cutting through the tendon in the polyblend suture specimens. Conclusion: The type of suture material has a significant effect on the biomechanical behavior of the suture-tendon interface. Clinical Relevance: The type of suture may influence early gap formation and ultimate healing of rotator cuff repairs.