Knotless Single-row Rotator Cuff Repair: A Comparative Biomechanical Study of 2 Knotless Suture Anchors

Abstract

The purpose of this study was to compare the gap formation during cyclic loading, maximum repair strength, and failure mode of single-row full-thickness supraspinatus repairs performed using 2 knotless suture anchors with differing internal suture-retention mechanisms in a human cadaver model. Nine matched pairs of cadaver shoulders were used. Full-thickness tears were induced by detaching the supraspinatus tendon from the greater tuberosity. Single-row repairs were performed with either type I (Opus Magnum PI; ArthroCare, Austin, Texas) or type II (ReelX STT; Stryker, Mahwah, New Jersey) knotless suture anchors. The repaired tendon was cycled from 10 to 90 N for 500 cycles, followed by load to failure. Gap formation was measured at 5, 100, 200, 300, 400, and 500 cycles with a video digitizing system. Anchor type or location (anterior or posterior) had no effect on gap formation during cyclic loading regardless of position (anterior, P=.385; posterior, P=.389). Maximum load to failure was significantly greater (P=.018) for repairs performed with type II anchors (288±62 N) compared with type I anchors (179±39 N). Primary failure modes were anchor pullout and tendon tearing for type II anchors and suture slippage through the anchor for type I anchors. The internal ratcheting suture-retention mechanism of type II anchors may have helped this anchor outperform the suture-cinching mechanism of type I anchors by supporting significantly higher loads before failure and minimizing suture slippage, potentially leading to stronger repairs clinically.

Biomechanical Strength of Rotator Cuff Repairs: A Systematic Review and Meta-regression Analysis of Cadaveric Studies

“…The inherent limitations of biomechanical studies have been enumerated. 23,28,32,39,42 In brief, the forces applied, tissue used, and healing environment in cadaveric studies are different from those in vivo. The use of ultimate failure load to predict construct performance has also been questioned.…”

Self-tapping ability of carbon fibre reinforced polyetheretherketone suture anchors

“…Currently unreinforced PEEK suture anchors require pre-tapped holes or the assistance of a metallic punch/anchor tip as the material is not capable of self-tapping. 18–20 However, the use of CFR-PEEK could potentially overcome this limitation, making self-tapping possible due to the improved mechanical properties. 3 Wall thickness within the head of the anchor determines the failure strength of the anchor under the applied torque during insertion of the anchor.…”

Comparison of Biomechanical Failure Loads Between Tape-Type and Conventional Sutures in Internal Knotless Anchor–Based Constructs

“…After every 50 cycles, the maximum load was increased incrementally by 10 N. The cyclic loading stage was concluded by either the completion of 50 cycles between 10 and 90 N or pullout of any suture, as described in previous studies. 9 The loading protocol simulated supraspinatus loading during activities of daily living. Gausden et al 11 showed that the supraspinatus generates less than 90 N of force in 8 of 10 common daily activities.…”

“…The preloading stage began with gradual tensioning of the sutures at 0.5-mm/s intervals until a preload of 10 N was achieved. 9,37 Preloading at 10 N persisted for 5 seconds before completion. Afterward, the cyclic loading stage began with loading between 10 and 20 N at 0.25 Hz for 50 cycles.…”