Mechanical analysis of suture attachment methods in toggle suture constructs

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.

Prospective bench top mechanical analysis.

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

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.

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).

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.

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.