A Biomechanical Comparison of the Pullout Strength of No. 2 FiberWire Suture and 2-mm FiberWire Tape in Bovine Rotator Cuff Tendons

Purpose: To biomechanically compare No. 2 polyblend suture with 2-mm polyblend tape in a bovine rotator cuff model as well as in isolation. Methods: Ten paired bovine infraspinatus specimens were randomly assigned to simple suture fixation with either No. 2 polyblend suture or 2-mm polyblend tape. Each specimen was subjected to cyclic testing followed by load-to-failure testing. Elongation, ultimate tensile load, and stiffness were determined. The failure method was recorded. Isolated suture specimens were also cycled and tested with the same protocol. Results: For tendon-suture specimens, testing showed no significant difference for elongation (1.44 +/- 0.41 mm v 1.90 +/- 1.15 mm, P = .192) or stiffness (67 +/- 13 N/mm v 66 +/- 11 N/mm, P = .757). Statistical significance was found for ultimate tensile load (168 +/- 73 N v 184 +/- 83 N, P = .046). The most common mode of failure for both groups of specimens was disruption of the tendon by the suture. Isolated suture specimens showed significant differences for ultimate tensile load (349 +/- 7 N v 937 +/- 93 N, P = .001) and stiffness (85 +/- 12 N/mm v 218 +/- 20 N/mm, P = .002) but not for elongation (0.26 +/- 0.05 mm v 0.19 +/- 0.04 mm, P = .124). Conclusions: Using the described testing method in bovine rotator cuff specimens, we found no difference in ultimate tensile load, stiffness, or elongation between the 2 tested sutures. Testing of the sutures in isolation showed that the 2-mm tape was approximately 3 times as stiff as the No. 2 suture and failed at 3 times the loads of the No. 2 suture. Clinical Relevance: The larger 2-mm tape does not diminish the biomechanical performance of rotator cuff-suture specimens in comparison to No. 2 suture. Although the effect of tape on the vascularity of the rotator cuff is not known, the larger tape does not negatively affect elongation, ultimate tensile load, or stiffness in this in vitro animal model.