Onlay Fixation With an All-Suture Anchor Provides Sufficient Biomechanical Stability for Lateral Extra-articular Tenodesis.

Abstract

Background: Spiked ligament staples (SLSs) and biocomposite suture anchors (BSAs) are commonly used onlay fixation devices for modified Lemaire lateral extra-articular tenodesis (LET). However, hardware prominence, tunnel penetration, footprint size, and irritation are documented issues. Knotless all-suture anchors (ASAs) are a promising alternative that mitigates these issues.

Purpose: To compare the biomechanical behavior of LET using ASAs with SLSs and BSAs under simulated anterolateral forces.

Study design: Controlled laboratory study.

Methods: Human iliotibial band grafts were harvested, whipstitched, and fixed onto fresh-frozen porcine femurs using ASAs, SLSs, or BSAs (n = 6/group). Each femur was placed in a custom fixture at the base of an electromechanical testing machine, oriented at 60° with iliotibial band grafts parallel to the load axis. Cyclic loading and load-to-failure testing were performed. Five millimeters of displacement was determined as the critical threshold for failure and survivorship analysis. Biomechanical outcomes included cyclic displacement, survivorship, and ultimate load.

Results: Cyclic displacement values after all load ranges were 4.25 ± 0.28 mm, 3.94 ± 0.71 mm, and 8.14 ± 1.68 mm for ASA, SLS, and BSA, respectively. No significant differences in cyclic displacement were found between ASA and SLS, whereas significant differences were found in each load range between BSA and both ASA and SLS (P < .05). Survivorship was 100% for ASA, 83% for SLS, and 0% for BSA. The ultimate loads were 257 ± 40 N, 300 ± 47 N, and 205 ± 24 N for ASA, SLS, and BSA, respectively; only SLS and BSA were significantly different (P = .002).

Conclusion: ASA onlay fixation for LET demonstrated comparable displacement to SLS and significantly lower displacement to BSA with greater survival during cyclic loading. ASA had comparable failure loading, with all groups exceeding the native anterolateral ligament failure load requirements. Therefore, ASA is a biomechanically viable alternative to SLS and BSA for iliotibial band fixation during LET.

Clinical relevance: ASAs are a biomechanically viable alternative to spiked staples and biocomposite suture anchors for LET onlay fixation, potentially mitigating complications associated with conventional techniques.