Tibial Eminence Avulsion Fracture Reduction With a Novel Adjustable-Loop Suture Repair Device: A Biomechanical Analysis

Background: The use of adjustable-loop devices (ALDs) has become increasingly common due to the ability to intraoperatively precondition a repair and retension the construct to provide additional stabilization. While ALDs have been supported for anterior cruciate ligament (ACL) repair and reconstruction, a biomechanical rationale for the addition of ALDs for the reduction of tibial eminence avulsion fracture is limited. Purpose: To biomechanically compare standard suture fixation to suture fixation with an ALD for the reduction of tibial eminence avulsion fractures. Study Design: Controlled laboratory study. Methods: Twenty porcine stifles were dissected of soft tissue, sparing the ACL. Type 3 tibial eminence avulsion fractures were created and reduced with suspensory suture fixation through 1 tunnel using either a standard suture technique (n = 10) or suture fixation with the addition of an ALD (n = 10). Repaired specimens underwent 10 preconditioning cycles to simulate intraoperative knee cycling, manual retensioning (ALD repairs only), cyclic loading between 10 and 50 N, 10 and 100 N, and 10 and 150 N for 100 cycles each, and then pull to failure. Cyclic elongation, cyclic stiffness, and ultimate load outcomes were statistically compared ( P < .05). Results: Total displacement after the cyclic loading protocol showed significantly less total elongation ( P < .001) for the ALD group (mean, 0.76 mm; 95% CI, 0.60-0.94 mm) compared with the control group (mean, 5.50 mm; 95% CI, 4.59-6.41 mm). All constructs survived cyclic loading. Significantly higher ultimate loads ( P = .023) were achieved by the ALD repairs (mean, 532 N; 95% CI, 461-604 N) compared with the standard repair (mean, 410 N; 95% CI, 327-495 N). There were no statistical differences in cyclic stiffness between repair groups for each load block. Conclusion: The addition of an ALD to suture fixation for tibial eminence avulsion fractures significantly reduced the total cyclic elongation by 86% and increased the ultimate load by 30% when compared with a standard suture fixation. The results suggest better time-zero biomechanics as compared with standard suture fixation. Clinical Relevance: Incorporation of ALD fixation into a standard suture repair may help stabilize fragment reduction, minimizing loss of reduction and potentially improving the bone healing response in tibial eminence fracture repair by minimizing micromotion. Future clinical studies are warranted to complement these biomechanical findings.