MRI analysis of the component-bone interface after TKA.

Overview

PURPOSE: The aim of the study is to describe and characterize the implant-bone interface of femoral, tibial and patellar components after TKA using magnet resonance imaging (MRI). SCOPE: Fifty-five patients who underwent MRI modified to reduce artifacts after TKA were identified retrospectively from medical records. This included 27 TKA with a zirconium femoral component and 28 TKA with conventional cobalt/chrome/molybdenum alloy component (CoCrMo). The MRIs were evaluated by two blinded, independent investigators and Cohen's Kappa was applied to determine the interobserver reliability. Excellent visibility, interobserver agreement and reliability was found for the interface of the tibial components, patellar buttons, and for femoral components made of zirconium. Conventional CoCrMo components caused significant artifact that interfered with the evaluation of the interface of femoral components. CONCLUSION: MRI performed with a special protocol allows good reproducibility of analysis of implant-bone interface at tibia and patella after TKA. The femoral interface was visualized for components made of zirconium. Conventional CoCrMo femoral components caused considerable artifact and interfered with the evaluation of the femoral interface. MRI tailored to reduce metallic susceptibility artifact can be a helpful tool for evaluation of prosthesis bone interface and may be helpful for the diagnosis of component loosening.