Gait analysis in ankle osteoarthritis and total ankle replacement.

BACKGROUND

Little information is available about gait changes in ankle osteoarthritis and total ankle replacement, and also about total ankle replacement patients' rehabilitation in the first year after surgery.

METHODS

Thirty subjects were included in this study: 15 unilateral post-traumatic ankle osteoarthritis patients and 15 age-/gender-matched control subjects. Patients were followed prospectively: preoperatively, at 3, 6, 9, and 12 months after total ankle replacement. The clinical-functional level was assessed by the American Orthopaedic Foot and Ankle Society ankle and the Short-Form-36 health survey score. 3D ankle-hindfoot kinematic-kinetic analysis was performed using a motion analysis and a two-plate force-platform system. Statistics included repeated measures analysis of variances, independent sample and paired Student's t-tests (significance alpha=0.05).

FINDINGS

Compared to normal subjects, ankle osteoarthritis caused significant reduction of the American Orthopaedic Foot and Ankle Society and Short-Form-36 score. In gait analysis, ankle osteoarthritis showed a significant deficiency in six of seven spatiotemporal variables, a decrease of the tri-planar ankle movement, a decrease of the second active maximal vertical and the maximal medial ground reaction force, a reduction of the sagittal and transverse ankle joint moments, a reduction of the ankle joint power. Three months after total ankle replacement surgery patients experienced a worsening of gait. At 12 months follow-up, all spatiotemporal variables were not different from the normal subjects (full rehabilitation); in six of 11 kinematic and kinetic variables there was a partial rehabilitation.

INTERPRETATION

This study provides data for the clinical-biomechanical understanding of the normal, arthritic, and total ankle replacement treated ankle during walking and the first year of rehabilitation.