Does knee revision after an articulated spacer implant provide normal gait restoration?

The aim of this study was to quantitatively evaluate gait parameters in patients who underwent a revision procedure after an interval articulated spacer for septic knee prosthesis.

Ten adult subjects underwent three-dimensional computerized gait analysis 12 months after second-stage knee revision procedure. Kinematic and kinetic parameters were acquired and compared with a normal reference population. Data were also compared with those collected in a previous study, in which the same cohort of patients underwent gait analysis 8-14 weeks after spacer implantation.

Kinematic and kinetic parameters did not show any significant difference between the affected and unaffected limb. Compared to normal reference population, patients treated with revision knee prosthesis showed a reduced mean gait velocity, step frequency, stride and step length, average knee range of motion, knee power and ground reaction forces. When comparing average data with those observed after spacer implant, no difference was observed in kinematic variables, while kinetic analysis demonstrated a significant improvement in knee power.

This study shows that 1 year after second-stage knee revision surgery, kinematic and kinetic values remain lower than those observed in a normal reference population. Only slight improvements in walking ability are shown, when analysing data in comparison with those collected after a preformed articulated knee spacer. This finding points out the long time to full functional recovery after knee revision surgery and the limited improvement of gait when compared to the one achieved at the time of spacer implant.