Comparison of walking energy cost between an anterior and a posterior ankle-foot orthosis in people with foot drop.

OBJECTIVE: To compare walking energy cost between an anterior and a posterior ankle-foot orthosis in people with foot drop.

DESIGN: Within-group comparisons.

PARTICIPANTS: Twenty-three adults (14 women, 9 men; mean age 56.8 years (standard deviation 15.4)) with foot drop.

METHODS: PARTICIPANTS were asked to walk for 5 min at their self-selected walking speed under 3 conditions: (i) with shoes only; (ii) with a posterior ankle-foot orthosis; (iii) with an anterior ankle-foot orthosis. Spatio-temporal gait para-meters (speed, step length and step frequency) and walking energy cost per unit of distance were assessed for each walking condition. A visual analogue scale was used to quantify participants' level of perceived comfort for the 2 orthosis.

RESULTS: Gait spatio-temporal parameters were higher with anterior ankle-foot orthoses than with posterior ankle-foot orthoses or shoes only. Walking energy cost per unit of distance was lower with anterior than posterior ankle-foot orthosis or shoes only ((mean ± standard error) 3.53 ± 1.00 vs 3.94 ± 1.27 and 3.98 ± 1.53 J·kg-1·m-1 respectively; p < 0.05) and level of perceived comfort was higher with anterior ((mean ± standard error) 8.00 ± 1.32) than with posterior ankle-foot orthosis ((mean ± standard error) 4.52 ± 2.57; p < 0.05).

CONCLUSION: In people with foot drop the use of anterior ankle-foot orthoses resulted in lower energy costs of walking and higher levels of perceived comfort compared with posterior ankle-foot orthoses. Anterior ankle-foot orthoses may enable people with foot drop to walk further with less physical effort than posterior ankle-foot orthoses.