Evaluation of effect of ankle-foot orthosis use on strength restoration of paretic dorsiflexors

OBJECTIVE: To assess whether a difference exists in restoration of strength between patients with a recent paresis of the dorsiflexors of the ankle using an ankle-foot orthosis (AFO) and patients without an AFO. DESIGN: Prospective case-control study. SETTING: Patients from regional hospitals, tested in a rehabilitation research center. PARTICIPANTS: Twenty-nine patients with a recent (6wk-1yr) peripheral paresis, alternately assigned to a group using an AFO or a control group. There was no significant difference in duration of the paresis and in torque at entering the study (T0) between the 2 groups. INTERVENTIONS: The use of an ankle-foot orthosis. MAIN OUTCOME MEASURES: Isometric torque production of ankle dorsiflexors, expressed as ratio of paretic and healthy side, in 2 measurement sessions, over a period of 6 weeks (T0-T6) with the ankle in 0 degrees and 30 degrees plantarflexion. RESULTS: Both groups had significant restoration of strength +/- standard deviation between T0 and T6 in 30 degrees flexion: non-AFO group 17% +/- 15%, AFO group 9% +/- 12%. No significant difference existed between the 2 groups (30 degrees p = .56). No significant shift in strength ratio 0 degrees :30 degrees occurred (AFO group p = .82). CONCLUSION: The use of an orthosis does not influence restoration of strength in patients with a recent peripheral paresis of the ankle dorsiflexors.