Background: A proximal rectus femoris (PRF) avulsion is primarily seen among elite-level athletes, which may require surgery after failed nonoperative treatment. Although suture bridge repair is a common surgical technique to treat these injuries, it is unclear whether a knotted or knotless suture bridge construct is biomechanically superior. Purpose: To biomechanically compare the failure load, stiffness, and number of cycles until failure of knotted versus knotless suture bridge repair for PRF avulsions. Study Design: Controlled laboratory study. Methods: A total of 8 pairs of fresh-frozen human cadaveric hemipelvises were included in this study. The PRF was harvested, along with its bony insertion at the anterior inferior iliac spine. Specimens underwent nondestructive testing in the intact state to assess linear stiffness. Each pair of specimens was randomly assigned to undergo knotted or knotless suture bridge repair. After surgical repair, the specimens underwent biomechanical testing consisting of a preconditioning phase, followed by pull to failure to assess the failure load, elongation at failure, stiffness, and mode of failure. Results: There was no difference in the failure load between knotless and knotted suture bridge repair (244 ± 124 vs 241 ± 136 N, respectively; P = .97). Elongation at failure was lower with the knotless construct compared with the knotted construct (19.7 ± 10.8 vs 34.3 ± 6.3 mm, respectively; P = .02). The most common mode of failure was suture anchor pullout. Intact stiffness was not significantly different between the knotless and knotted groups (56.0 ± 14.7 vs 57.4 ± 19.5 N/mm, respectively; P = .99). Repair stiffness of the knotless group was not significantly different from the intact state (50.9 ± 12.6 vs 56.0 ± 14.7 N/mm, respectively; P = .79). The knotted group exhibited significantly lower repair stiffness compared with the intact state (38.3 ± 19.0 vs 57.4 ± 19.5 N/mm, respectively; P = .01). The knotless group demonstrated significantly higher stiffness as a percentage of the intact state compared with the knotted group (93.7% ± 21.1% vs 65.0% ± 22.1%, respectively; P = .03). Conclusion: This study demonstrated that the failure load between knotless and knotted suture bridge repair was not significantly different. However, stiffness as a percentage of the intact state in the knotless group was significantly higher than that in the knotted group. Therefore, this study suggests that the knotless suture bridge repair technique may be a better surgical option than the knotted suture bridge repair technique to restore stiffness of the PRF. Clinical Relevance: Elucidating a biomechanically superior repair method for PRF avulsions may inform optimal surgical techniques for treating these injuries, leading to lower failure rates and superior outcomes in patients.
Nishimura et al. (Sun,) studied this question.