Gap Formation and Fixation Strength After Unicortical Quadriceps Tendon Repair with All-Suture Anchors.

Background: All-suture anchors (ASAs) significantly reduced gap formation and increased strength compared with traditional fixation in a transosseous cadaveric quadriceps tendon repair model. However, the biomechanical performance of ASAs for unicortical quadriceps tendon repair has not been evaluated. Hypothesis: ASAs would reduce gap formation and exhibit comparable stiffness, yield load, and ultimate load to knotless hard-body suture anchors (SAs) for unicortical quadriceps tendon repair. Study Design: Controlled laboratory study. Methods: Eight matched pairs of male cadaveric knees were used to compare ASA and SA control repairs. Distal quadriceps tendons were prepared with 2 Krackow sutures using 1.3-mm suture tape. Sutures were fixed unicortically with 2 anchors using 2.6-mm ASAs or 4.75-mm SAs. Knees were actuated from 5° to 90° of flexion via the quadriceps tendon for 10 native preconditioning cycles and 250 cycles after repair at 0.1 Hz, with a peak force of 150 N per cycle. Repairs were loaded to failure at 50 mm/min. Gap formation (mm) during cyclic loading and stiffness (N/mm), yield load (N), and ultimate load (N) during load to failure were statistically compared between groups using paired Results: The ASA repair had significantly less gap formation at cycle 250 compared with the control repair (Δ = 4.2 mm [95% CI, 2.9 to 5.3 mm]; Conclusion: Unicortical quadriceps tendon repair with ASAs reduced gap formation by 43% compared with hard-body SAs. No significant differences in stiffness or ultimate load were observed, although a significantly greater yield load was found for the SA controls. Clinical Relevance: ASAs are a biomechanically viable alternative to hard-body SAs for unicortical quadriceps tendon repair, potentially resulting in less gap formation.