MRI following UKA: The component-bone interface.

BACKGROUND Loosening is one of the major long-term failure modes in unicondylar knee arthroplasty (UKA). The aim of the study is to describe and characterize implant-bone interface of femoral and tibial components after UKA by means of magnet resonance imaging (MRI). MATERIAL AND METHODS MRI tailored to reduce metallic artefact of the knee after medial UKA was performed in 10 patients as a pilot study. The component-bone interface at femoral and tibial components was evaluated by two independent investigators. They gave degree of confidence to their evaluation of each parameter on a five-point scale. Inter-observer reliability was determined. RESULTS Artefacts provoked by the implants were rare. Inter-observer reliability and confidence were excellent for the femoral interface. They were lower at the tibial interface but results were still satisfactory. CONCLUSIONS Tailored MRI allows reproducible analysis of the component-bone interface after UKA. It is helpful in assessment of suspected loosening after UKA.