BACKGROUND AND PURPOSE: Abnormal knee hyperextension during the stance phase (genu recurvatum) is a common gait abnormality in persons with hemiparesis due to stroke. While ankle-foot orthoses (AFOs) are often used to prevent genu recurvatum by maintaining ankle dorsiflexion during the stance phase, AFOs reduce ankle joint mobility. Functional electrical stimulation (FES) is an alternative to the use of AFO for producing appropriately timed ankle dorsiflexion and with prolonged timing may also have value for reducing genu recurvatum. CASE DESCRIPTION: A 51-year-old man with chronic stroke was the subject of this case study. The patient had excessive plantarflexion during stance phase (ie, dynamic equinus foot), with associated genu recurvatum. INTERVENTION: Evaluation included clinical examination, instrumented gait analysis, 10-meter walk test, and 6-minute walk test. The patient underwent a trial of botulinum toxin to the plantarflexor muscles that was not effective for controlling the genu recurvatum. A subsequent trial with surface FES to elicit dorsiflexion during gait was effective, and he subsequently received an implanted FES system. OUTCOMES: Stimulation-induced contraction of the dorsiflexors during terminal swing phase resulted in improved ankle dorsiflexion at initial contact. Moreover, extension of stimulation into the loading phase ensured tibial advancement, which limited knee hyperextension. The patient was reevaluated 12 months following implantation with continued positive outcomes. DISCUSSION: This case study illustrates the potential value of prolonged timing of dorsiflexor FES to manage genu recurvatum attributed to a dynamic equinus foot in a stroke survivor.
BACKGROUND AND PURPOSE: Abnormal knee hyperextension during the stance phase (genu recurvatum) is a common gait abnormality in persons with hemiparesis due to stroke. While ankle-foot orthoses (AFOs) are often used to prevent genu recurvatum by maintaining ankle dorsiflexion during the stance phase, AFOs reduce ankle joint mobility. Functional electrical stimulation (FES) is an alternative to the use of AFO for producing appropriately timed ankle dorsiflexion and with prolonged timing may also have value for reducing genu recurvatum. CASE DESCRIPTION: A 51-year-old man with chronic stroke was the subject of this case study. The patient had excessive plantarflexion during stance phase (ie, dynamic equinus foot), with associated genu recurvatum. INTERVENTION: Evaluation included clinical examination, instrumented gait analysis, 10-meter walk test, and 6-minute walk test. The patient underwent a trial of botulinum toxin to the plantarflexor muscles that was not effective for controlling the genu recurvatum. A subsequent trial with surface FES to elicit dorsiflexion during gait was effective, and he subsequently received an implanted FES system. OUTCOMES: Stimulation-induced contraction of the dorsiflexors during terminal swing phase resulted in improved ankle dorsiflexion at initial contact. Moreover, extension of stimulation into the loading phase ensured tibial advancement, which limited knee hyperextension. The patient was reevaluated 12 months following implantation with continued positive outcomes. DISCUSSION: This case study illustrates the potential value of prolonged timing of dorsiflexor FES to manage genu recurvatum attributed to a dynamic equinus foot in a stroke survivor.
Authors: Andrew J Meyer; Ilan Eskinazi; Jennifer N Jackson; Anil V Rao; Carolynn Patten; Benjamin J Fregly Journal: Front Bioeng Biotechnol Date: 2016-10-13