Mechanical analysis of suture attachment methods in toggle suture constructs.

Abstract

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&#x2009;=&#x2009;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&#x2009;N) for constructs D (P&#x2009;&#x2264;&#x2009;.048) and G (P&#x2009;&#x2264;&#x2009;.048). Mean construct stiffness of D (53.52&#x2009;N/mm) and E (53.6&#x2009;N/mm) was greater than that of the 6 other constructs (P&#x2009;&#x2264;&#x2009;.040). Construct A sustained the most elongation in acute (23.47&#x2009;mm; P&#x2009;<&#x2009;.001) and cyclic (18.53&#x2009;mm; P&#x2009;<&#x2009;.003) loading. Cycles to failure was greater for construct C (622 cycles) compared with constructs A, B, and H (P&#x2009;=&#x2009;.008, P&#x2009;=&#x2009;.009, and P&#x2009;=&#x2009;.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.