Model-based Radiostereometric Analysis of an Uncemented Mobile-bearing Total Ankle Arthroplasty System

Abstract

Model-based radiostereometric analysis (MBRSA) of a total ankle arthroplasty (TAA) prosthesis was studied for the first time.

The TAA MBRSA system precision was determined from the double exams of 20 patients implanted with the Mobility(TM). The MTE for any direction was 0.07mm for the tibial component. The MTE was 0.09mm and the MRE was 0.51° for the talar component. The MTPM detection limits were 0.22mm and 0.85mm for the tibial and talar components.

Both components followed the typical subsidence-stabilization pattern. There was little detectable continuous migration at one to two years. The median(range) MTPM at two years was 0.96mm(0.17-2.28mm) and 1.23mm(0.39-1.9 mm) for the tibial and talar components.

There was no detectable inducible displacement observed for any components at two years, except one talar component. The median(range) MTPM induced by the loading at two years was 0.08mm(0.03-0.18mm) and 0.39mm(0.27-1.06mm) for the tibial and talar components.