title: Ankle-foot orthoses that restrict dorsiflexion improve walking in polio survivors with calf muscle weakness.
abstract: In polio survivors with calf muscle weakness, dorsiflexion-restricting ankle-foot orthoses (DR-AFOs) aim to improve gait in order to reduce walking-related problems such as instability or increased energy cost. However, evidence on the efficacy of DR-AFOs in polio survivors is lacking. We investigated the effect of DR-AFOs on gait biomechanics, walking energy cost, speed, and perceived waking ability in this patient group. Sixteen polio survivors with calf muscle weakness underwent 3D-gait analyses to assess gait biomechanics when walking with a DR-AFOs and with shoes only. Ambulant registration of gas-exchange during a 6 min walk test determined walking energy cost, and comfortable gait speed was calculated from the walked distance during this test. Perceived walking ability was assessed using purposely-designed questionnaires. Compared with shoes-only, walking with the DR-AFOs significantly increased forward progression of the center of pressure (CoP) in mid-stance and it reduced ankle dorsiflexion and knee flexion in mid- and terminal stance (p < 0.05). Furthermore, walking energy cost was lower (-7%, p = 0.052) and gait speed was higher (p = 0.005). Patients were significantly more satisfied, felt safer, and less exhausted with the DR-AFO, compared to shoes-only (p < 0.05). DR-AFO effects varied largely across patients. Patients who walked with limited forward CoP progression and persisting knee extension during the shoes-only condition seemed to have benefitted least from the DR-AFO. In polio survivors with calf muscle weakness, DR-AFOs improved gait biomechanics, speed, and perceived walking ability, compared to shoes-only. Effects may depend on the shoes-only gait pattern, therefore further study is needed to determine which patients benefit most from the DR-AFO.
authors.affiliation: Department of Rehabilitation, Academic Medical Center, University of Amsterdam, The Netherlands. Electronic address: h.e.ploeger@amc.uva.nl.
authors.forename: Hilde E
authors.initials: HE
authors.lastname: Ploeger
authors.affiliation: Department of Rehabilitation, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: Sicco A
authors.initials: SA
authors.lastname: Bus
authors.affiliation: Department of Rehabilitation, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: Merel-Anne
authors.initials: MA
authors.lastname: Brehm
authors.affiliation: Department of Rehabilitation, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: Frans
authors.initials: F
authors.lastname: Nollet
mesh_terms: D000328:Adult; D000368:Aged; D000843:Ankle Joint / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D004734:Energy Metabolism; D005260:Female; D061826:Foot Orthoses; D020233:Gait Disorders, Neurologic / Q000503:physiopathology* / Q000534:rehabilitation; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000503:physiopathology*; D011051:Poliomyelitis / Q000503:physiopathology* / Q000534:rehabilitation; D012775:Shoes; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology*
keywords: Ankle-foot orthosis; Calf muscle weakness; Gait analysis; Poliomyelitis; Walking energy cost