Mechanical analysis of suture attachment methods in toggle suture constructs

Vet Surg. 2018 Sep 21. [Epub ahead of print]

OBJECTIVE: To determine the effect of the method used to attach OrthoFiber #5 to a 1/8-in Securos toggle rod on the mechanical properties of the resulting construct.

STUDY DESIGN: Prospective bench top mechanical analysis.

SAMPLE POPULATION: One hundred twenty-eight OrthoFiber #5-toggle rod suture constructs.

METHODS: Toggle-suture constructs (groups A-H) were prepared by using 8 methods to attach OrthoFiber #5 to a 1/8-in toggle rod (n = 16 constructs/group). A servohydraulic materials-testing machine was used to test each toggle-suture construct in tension. Mean load to failure, cycles to failure, construct stiffness, and suture elongation under static and cyclic loading were compared among types of constructs.

RESULTS: Mean load to failure was greatest (>500 N) for constructs D (P ≤ .048) and G (P ≤ .048). Mean construct stiffness of D (53.52 N/mm) and E (53.6 N/mm) was greater than that of the 6 other constructs (P ≤ .040). Construct A sustained the most elongation in acute (23.47 mm; P < .001) and cyclic (18.53 mm; P < .003) loading. Cycles to failure was greater for construct C (622 cycles) compared with constructs A, B, and H (P = .008, P = .009, and P = .010, respectively).

CONCLUSION: The method used to attach OrthoFiber #5 to a 1/8-in toggle rod influenced the mechanical properties of the construct. No one construct outperformed other groups in all areas of testing, but construct D was superior when mean load to failure and construct stiffness were considered.

CLINICAL IMPACT:Construct D, with OrthoFiber #5, passed straight through the toggle rod eyelet, may provide superior stability and resistance to fatigue failure to toggle-in repairs of coxofemoral luxations.