Effect of long-term use of ankle-foot orthoses on tibialis anterior muscle electromyography in patients with sub-acute stroke: A randomized controlled trial

Abstract

LAY ABSTRACTAnkle-foot orthoses (AFOs) are often used to improve walking after stroke. However, it is unknown whether early or later provision of AFOs affects muscle activity, and what are the effects of long-term AFO use after stroke. Some clinicians fear that early use of AFO after stroke has negative effects on muscles around the ankle. Therefore, we studied the effect of AFO use on the tibialis anterior muscle in 26 subjects after stroke. Subjects were prescribed an AFO in week 1 of the study, or 8 weeks later. Muscle activity was measured 4 times over a period of 26 weeks. We found that AFO use reduced muscle activity levels compared with walking without an AFO within 1 measurement. However, longterm use of an AFO for a period of 26 weeks did not affect muscle activity. These effects were the same for the subjects provided with the AFO in week 1 or 8 weeks later. This study did not find any negative effects on activity of the tibialis anterior muscle with long-term use of an AFO early after stroke.Objective: To determine: (i) whether the use of ankle-foot orthoses over a period of 26 weeks affects tibialis anterior muscle activity; (ii) whether the timing of provision of ankle-foot orthoses (early or delayed) affects the results; (iii) whether the provision of ankle-foot orthoses affects tibialis anterior muscle activity within a single measurement. Design: Randomized controlled trial. Subjects: Unilateral hemiparetic subjects, a maximum of 6 weeks post-stroke. Methods: Subjects were assigned randomly to early (at inclusion; week 1) or delayed provision of anklefoot orthoses (8 weeks later; week 9). Tibialis anterior electromyography was measured with and without ankle-foot orthoses, in study weeks 1, 9, 17 and 26. Results: A total of 26 subjects were analysed. In a single measurement, use of an ankle-foot orthosis significantly reduced the activity levels of the tibialis anterior muscle during the swing phase (p = 0.041) compared with walking without an ankle-foot orthosis. During the 26-week follow-up, no changes were found in tibialis anterior muscle activity in the swing phase without an ankle-foot orthosis, both within-groups (p = 0.420 early; p = 0.282 delayed), and between-groups (p = 0.987). After 26 weeks, no differences were found in tibialis anterior muscle activity between both groups in the swing phase, with (p = 0.207) or without ankle-foot orthoses (p = 0.310). Conclusion: Use of ankle-foot orthoses post-stroke reduced tibialis anterior muscle activity in the swing phase within one measurement; however, long-term use of ankle-foot orthoses for 26 weeks did not affect such activity. Early or delayed provision of ankle-foot orthoses did not affect the findings. The results indicate that there is no need to fear negative consequences on tibialis anterior-activity because of long-term AFO-use (early) after stroke.

Gait and Muscle Activity Changes in Patients in the Recovery Phase of Stroke with Continuous Use of Ankle–Foot Orthosis with Plantarflexion Resistance

“…Nikamp et al reported that at an average of 30 days after stroke onset, TA muscle activity decreased more during swing when using a PAFO than when not using a PAFO, but there was no significant difference in muscle activity with or without a PAFO after 26 weeks. 5 ) However, we found that in patients with stroke, 2-month use of an AFO-PR that allows plantarflexion of the ankle joint during loading response resulted in significant increases in TA %EMG activity during loading response compared with the other phases.…”

“…In contrast, Nikamp et al reported that at an average of 30 days after stroke onset, TA muscle activity decreased more during swing when using a PAFO than when not using a PAFO, but there was no significant difference in muscle activity with or without a PAFO after 26 weeks. 5) The AFO-PS and PAFO used in these previous studies may have affected TA muscle activity by stopping plantarflexion during loading response. Recently, AFOs with plantarflexion resistance (AFO-PR) have been developed to aid the eccentric contraction of the TA muscle in the heel rocker.…”

“…In contrast, Nikamp et al reported that at an average of 30 days after stroke onset, TA muscle activity decreased more during swing when using a PAFO than when not using a PAFO, but there was no significant difference in muscle activity with or without a PAFO after 26 weeks. 5 )…”

The sooner the better?! Providing ankle-foot orthoses in the rehabilitation after stroke

“…67 These beneficial effects on functional outcomes were found without negative consequences of AFO-use on muscle activity of the tibialis anterior. 106 In addition, decreased foot-clearance is reported as an increased risk for stumbling and falls. 11 AFOs are provided to improve foot-clearance in swing phase, 14 under the assumption that this improves safety of walking.…”

“…were studied and several outcome levels were used. The effects of timing of providing AFOs on clinical scales, 65,83 lower limb kinematics 82,92 and tibialis anterior muscle electromyography 106 have been previously reported. In the current paper, the early group (provided with AFOs after inclusion), was compared with the delayed group (not yet provided with AFOs)…”