5kn ag x

The theoretical model of mechanical testing was accomplished using the well-known guidelines of ASTM F1717-04 "Static and Dynamic Test Method for Spinal Implant Assemblies in a Corpectomy Model" to evaluate the mechanical properties of the 6.5 mm rod under static and dynamic loading. Non-destructive load was applied during flexion/extension and torsion testing9 (link)20 (link)22) . In order to apply the load to the corpectomy models, a custom-made system was designed for the test machines. Flexion/extension tests were accomplished using an electromechanical universal testing machine (Shimadzu 5kN AG-X, Japan) (Fig. 1). To simulate spine-loading conditions, the samples were subjected to a load of 100 N to ensure an 8.4-Nm moment with a velocity of 5 mm min^-1.7 (link)22) To examine torsional loading, the UHMWPE blocks were mounted in a torsion testing machine (TecQuipment, Ltd., United Kingdom) and subjected to rotational displacement of 0.5° s^-1 to an end point of 5.0° (Fig. 3)19 (link)20) (link). The obtained data were analyzed using SPSS v.15. for Windows (SPSS Inc., Chicago, IL, USA). The non-parametric one-way analysis of variance was used for categorical comparisons. Statistical significance level was set at p<0.05.

The right knees of each rabbit were prepared for biomechanical testing. Medial menisci were dissected from tibia, and two 2.5 mm-diameter samples for each meniscus were taken; one from the healthy middle part and another involving the defected areas of each medial menisci. Cylindrical samples for indentation testing were obtained. After measuring their thickness, all samples were placed in a specially designed 2.5 mm-diameter steel pot. The specimens were subjected to compression load with a flat tipped indenter of the same diameter. All tests were performed under axial loading with an electromechanical actuator (5 kN AG-X; Shimadzu, Kyoto, Japan) (Fig. 7).Fig. 7

Schematic view of indentation tests.

Fig. 7