All-suture anchor and unicortical button show comparable biomechanical properties for onlay subpectoral biceps tenodesis

Abstract

Hypothesis: The purpose of this study was to biomechanically evaluate onlay subpectoral long head of the biceps (LHB) tenodesis with all-suture anchors and unicortical buttons in cadaveric specimens. Methods: After evaluation of bone mineral density, 18 fresh-frozen, unpaired human cadaveric shoulders were randomly assigned to 2 groups: One group received an onlay subpectoral LHB tenodesis with 1 all-suture anchor, whereas the other group received a tenodesis with 1 unicortical button. The specimens were mounted in a servo-hydraulic material testing system. Tendons were initially loaded from 5 N to 100 N for 5000 cycles at 1 Hz. Displacement of the repair constructs was observed with optical tracking. After cyclic loading, each specimen was loaded to failure at a rate of 1 mm/s. Results: The mean displacement after cyclic loading was 6.77 ± 3.15 mm in the all-suture anchor group and 8.41 ± 3.17 mm in the unicortical button group (P = not significant). The mean load to failure was 278.05 ± 38.77 N for all-suture anchor repairs and 291.36 ± 49.69 N for unicortical button repairs (P = not significant). The most common mode of failure in both groups was LHB tendon tearing. There were no significant differences between the 2 groups regarding specimen age (58.33 ± 4.37 years vs. 58.78 ± 5.33 years) and bone mineral density (0.50 ± 0.17 g/cm2 vs. 0.44 ± 0.19 g/cm2). Conclusion: All-suture anchors and unicortical buttons are biomechanically equivalent in displacement and load-to-failure testing for LHB tenodesis. All-suture anchors can be considered a validated alternative for onlay subpectoral LHB tenodesis.

Keywords

• All-suture anchor
• unicortical biceps button
• long head of the biceps tendon
• LHB
• LHB tenodesis
• subpectoral tenodesis