Gait asymmetry persists following unilateral and bilateral total ankle arthroplasty

Total ankle arthroplasty (TAA) improves gait symmetry in patients with unilateral end-stage ankle arthritis but has not been studied in patients undergoing bilateral TAA (B-TAA), and few studies compare TAA patients to control subjects. The purpose of this study was to compare gait symmetry in U-TAA and B-TAA patients and healthy controls. Using prospective databases, 19 unilateral and 19 bilateral ankle arthritis patients undergoing TAA were matched to 19 control subjects by age, sex, and BMI. The Normalized Symmetry Index (NSI) was determined for joint mechanics and ground reaction forces (GRF) during walking trials at a single visit for controls and preoperatively and 1 to 2 years postoperatively for TAA patients. Data was analyzed using linear mixed-effects models to determine differences among time points and cohorts at a significance of α = 0.05. Following surgery, B-TAA and U-TAA experienced improved peak plantarflexion moment symmetry (p = 0.017) but remained less symmetric than controls. B-TAA patients had more symmetry than U-TAA patients during peak weight acceptance GRF (p = 0.002), while U-TAA patients had greater peak dorsiflexion symmetry than B-TAA patients. TAA patients demonstrated more asymmetry compared to control subjects for all outcome measures. There was no significant impact of TAA on gait symmetry for GRF or peak ankle angles, and neither U-TAA nor B-TAA was consistently associated with higher gait symmetry. These results indicate that TAA improves symmetry during peak plantarflexion moment, and that significant gait asymmetry persists for B-TAA and U-TAA patients compared to healthy participants.