2025 ISAKOS Congress in Munich, Germany

2025 ISAKOS Biennial Congress Paper


Suture Repair With a Novel Adjustable-Loop Device Reduces Fragment Displacement in Tibial Eminence Avulsion Fractures: A Biomechanical Analysis

Brittany M Glaeser, M.S, Bonita Springs, FL UNITED STATES
Jonathan Riboh, MD, Chicago, IL UNITED STATES
Oliver L Hauck, M.S., Naples, FL UNITED STATES
Coen Abel Wijdicks, PhD, Naples, Florida UNITED STATES

Arthrex, Inc, Naples, Florida, UNITED STATES

FDA Status Cleared

Summary

The study objective was to biomechanically compare standard fixation to adjustable-loop device suture fixation for tibial eminence avulsion fractures in a porcine cadaveric model.

Abstract

Introduction

Tibial eminence avulsion fractures occur when the bone surrounding the anterior cruciate ligament (ACL) fractures prior to ligament rupture. Surgical intervention for severe fractures involves reduction of the bony avulsion commonly using sutures tied over a tibial metal cortical button. The addition of an adjustable-loop cortical button device (ALD) to suture fixation is a novel technique variation that may reduce the avulsed fragment by removing initial creep and adjusting initial compressive forces via re-tensioning.

Objective

The study objective was to biomechanically compare standard fixation to ALD suture fixation for tibial eminence avulsion fractures in a porcine cadaveric model.

Methods

Twenty porcine stifles were dissected of all muscle and ligamentous tissue surrounding the ACL. Specimens were secured to a materials tensile testing machine with ACL fibers parallel to the direction of the load. Initial creep in the ACL was removed by cyclically loading the ligament between 10-50 N, 10-100 N, and 10-150 N for 100 cycles each at 1 Hz. Following native testing, a Type III tibial eminence avulsion fracture was created and subsequently repaired. Fracture reduction was achieved via suspensory suture fixation through a single tunnel using either a standard technique tied over a metal button (n=10) or an ALD (n=10). Intraoperative knee cycling was simulated by 10 pre-conditioning cycles at 0.5 Hz. Specimens were manually re-tensioned (ALD repairs only) and secured with a knot. Repaired specimens then underwent the same cyclic loading sequence as the native specimens with endpoint pull-to-failure at a rate of 200 mm/min. Cyclic elongation, cyclic stiffness, and ultimate load outcomes were statistically analyzed using a one-way RM ANOVA with a post-hoc Bonferroni multiple comparisons procedure (p<0.05) and a Student’s t-test (p<0.05).

Results

Total displacement after the cyclic loading protocol showed significantly less total elongation (p<0.001) for the ALD group (0.76 ± 0.23 mm) compared to the control group (5.50 ± 1.28 mm). There were no statistical differences in cyclic stiffness between repair groups. All constructs survived cyclic loading and were subsequently pulled to failure. Significantly higher ultimate loads (p= 0.023) were achieved by the ALD repairs (532 ± 100 N) compared to the control group (410 ± 118 N).

Conclusion

The study found reduced cyclic elongation for the ALD repair compared to the standard repair suggesting that ALDs maintain a greater reduction of the avulsion fracture at time-zero. The study also found that the ALD repair obtained higher ultimate loads than the standard repair, better restoring native ACL function.

CLINICAL RELEVANCE: Adjustable-loop devices provide the ability to intraoperatively precondition and re-tension the tibial eminence avulsion repair, which may mitigate gap formation and restore native function during fracture healing and early rehabilitation.