Inducible Displacement of a Trabecular Metal Tibial Monoblock Component

Radiostereometric analysis is a highly accurate technique that can be used for measuring micromotion at the bone-implant interface. The purpose of this study was to compare the inducible displacement of the uncemented Trabecular Metal (TM; Zimmer, Warsaw, Ind) tibial monoblock component with that of a cemented implant. Inducible displacement of 14 uncemented TM components and 11 cemented components was measured 24 to 48 months postoperatively. Longitudinal migration of the implants was also measured with radiostereometric analysis at 6, 12, and 24 months postoperatively. The uncemented TM group had significantly lower inducible displacement than the cemented components. Significant correlations were found between longitudinal migration and the inducible displacement tests. The low values of inducible displacement in the TM group indicated good fixation and a promising long-term prognosis.