Biomechanical Comparison Between Double-Row Repair and Soft Tissue Tenodesis for Treatment of Proximal Rectus Femoris Avulsions

Background: Some patients with proximal rectus femoris (PRF) avulsions require surgical treatment after failed nonoperative treatment. There is no consensus on the superiority of suture anchor repair with the suture-bridge repair (SBR) technique versus tenodesis repair (TR) for PRF avulsions. Purpose: To compare the failure load and elongation at failure between SBR and TR and to compare the stiffness of these 2 repair techniques versus the native state. Study Design: Controlled laboratory study. Methods: Seven pairs of human cadaveric hemipelvises were dissected to the PRF and sartorius origins. Each specimen underwent preconditioning followed by a distraction test to determine the stiffness of the native specimen. One specimen of each pair received one of the repair methods (SBR or TR), while the other specimen in the pair received the other repair technique. After repair, each specimen underwent preconditioning followed by a pull to failure. The failure load, elongation at failure, stiffness, mode of failure, and stiffness as a percentage of the native state were determined for each repair. Results: The SBR group exhibited a stronger failure load (223 +/- 51 N vs 153 +/- 32 N for the TR group; P = .0116) and significantly higher stiffness as a percentage from the native state (70.4% +/- 19% vs 33.8% +/- 15.5% for the TR group; P = .0085). While the stiffness of the repair state in the SBR group (41.5 +/- 9.4 N/mm) was not significantly different from that of the native state (66.2 +/- 36 N/mm), the stiffness of the repair state in the TR group (20.3 +/- 7.5 N/mm) was significantly lower compared with that of the native state (65.4 +/- 22.1 N/mm; P < .001) and repair state in the SBR group (41.5 +/- 9.4 N/mm; P = .02). The SBR group primarily failed at the repair site (71%), and the TR group primarily failed at the suture-sartorius interface (43%) and at the muscle (29%). Conclusion: SBR and TR specimens were significantly weaker than the native tendon. The stiffness of the SBR was equivalent to that of the native tendon, while TR was significantly less stiff than the native tendon. The SBR was superior to TR in terms of failure load, stiffness, and percentage stiffness from the native state.