Association between improved trunk stability and walking capacity using ankle-foot orthosis in hemiparetic patients with stroke: evidence from three-dimensional gait analysis.

BACKGROUND: Restoration of both normal movement of the pelvis and centre of mass is a primary goal of walking rehabilitation in post-stroke patients because these movements are essential components of effective gait. The aim of this study is to quantitatively analyze the effect of ankle-foot orthosis on walking ability, and to investigate the correlation between improvements in trunk motion and walking capacity. METHODS: Walking speed, centre of mass displacement, and pelvic movements were examined in 20 post-stroke hemiparetic patients with and without ankle-foot orthosis using three-dimensional motion analysis. RESULTS: Using ankle-foot orthosis improved walking speed, pelvic rotation and tilt, and lateral and vertical displacements of the centre of mass (P < 0.01). Moreover, the gait asymmetry index was significantly decreased (P < 0.01), and the Functional Ambulation Categories score improved significantly when patients used an ankle-foot orthosis (P < 0.05). There was significant correlation between improvements in the walking capacity and the displacement of the centre of mass in both vertical and lateral directions (P < 0.01). CONCLUSIONS: Using ankle-foot orthosis improves the walking capacity by improving the stability and concordant of the trunk in hemiplegic patients. The improvement in the walking capacity from using an ankle-foot orthosis may be attributed to its prevention of foot drop and compensation for the instability of the ankle joint.