Interference Screw Versus Suture Anchor Fixation for Subpectoral Tenodesis of the Proximal Biceps Tendon: A Cadaveric Study

Purpose: The purpose of this study was to compare the biomechanical properties of 2 fixation methods for subpectoral proximal biceps tenodesis. Methods: In 9 matched pairs of cadaveric shoulders, an open subpectoral tenodesis was performed I cm proximal to the inferior border of the pectoralis major tendon by use of either an 8 x 12-mm Bio-Tenodesis screw (Arthrex, Naples, FL) with No. 2 FiberWire sutures (Arthrex) or a 5.5-mm Bio-Corkscrew double-loaded suture anchor (Arthrex) with No. 2 FiberWire sutures. The specimens were dissected and mounted in a material testing machine. Cyclic loading (20 to 60 N, 100 cycles, 0.5 mm/s, 5-N preload) was performed, followed by an unloaded 30-minute rest, a 5-N preload, and a load-to-failure protocol (1.25 mm/s) with a 100-lb load cell. Ultimate load (in Newtons), stiffness (in Newtons per millimeter), and modes of failure were recorded. Data were analyzed by use of paired t tests and Wilcoxon signed rank tests. Results: Proximal biceps tenodeses with Bio-Tenodesis screws had a significantly higher mean load to failure (169.6 +/- 50.5 N; range, 99.6 to 244.7 N) than those with Bio-Corkscrew suture anchors (68.5 +/- 33.0 N; range, 24.2 to 119.4 N) (P = .002). Bio-Tenodesis screws also had a significantly higher stiffness (34.1 +/- 9.0 N/mm; range, 20.6 to 48.9 N/mm) than Bio-Corkscrews (19.3 +/- 10.5; range, 5.9 to 32.9 N/mm) (P = .038). Conclusions: In this cadaveric study the Bio-Tenodesis screw showed a statistically significantly higher load to failure and significantly higher stiffness than the Bio-Corkscrew anchor when used for tenodesis of the proximal biceps tendon in a subpectoral location. Clinical Relevance: Biomechanical comparison of these 2 fixation techniques provides information on stiffness and load to failure of alternate fixation methods.