Effects of an anterior ankle-foot orthosis on postural stability in stroke patients with hemiplegia

Objective: To evaluate the effects of an anterior leaflet ankle-foot orthosis (AFO) on postural stability in stroke patients with hemiplegia. Design: Twenty-one stroke patients with hemiplegia resulting from new-onset stroke and ten normal subjects were included in this study. The SMART balance master system was used to assess the postural stability by measuring the ankle strategy, maximal stability, and velocity of center-of-gravity (COG) movement under the following six conditions: (1) eyes open and fixed support (EOFS), (2) eyes closed and fixed support (ECFS), (3) sway-referenced vision and fixed support (SVFS), (4) eyes open and sway-referenced support (EOSS), (5) eyes closed and sway-referenced support (ECSS), and (6) sway-referenced vision and support (SVSS). Each patient was tested with and without an anterior AFO as compared with normal subjects. Results: When wearing an anterior AFO, patients used ankle strategy more than hip strategy to maintain postural stability in all the six sensory conditions (P < 0.05). An anterior AFO also provided stroke patients with better maximal stability under relatively challenging conditions such as SVFS, EOSS, and ECSS (P < 0.05), but the effect was not apparent in the conditions without external perturbation (EOFS and ECFS) and the most difficult condition (SVSS). The velocity of COG movement was lowered when wearing an anterior AFO in stroke patients, and significant differences existed in the EOFS, ECFS, ECSS, and SVSS conditions (P < 0.05). Conclusions: In the early stage of recovery, the use of an anterior AFO may assist stroke patients with hemiplegia to improve their postural stability.