Precision orthotics: optimising ankle foot orthoses to improve gait in patients with neuromuscular diseases; protocol of the PROOF-AFO study, a prospective intervention study.

In patients with neuromuscular disorders and subsequent calf muscle weakness, metabolic walking energy cost (EC) is nearly always increased, which may restrict walking activity in daily life. To reduce walking EC, a spring-like ankle-foot-orthosis (AFO) can be prescribed. However, the reduction in EC that can be obtained from these AFOs is stiffness dependent, and it is unknown which AFO stiffness would optimally support calf muscle weakness. The PROOF-AFO study aims to determine the effectiveness of stiffness-optimised AFOs on reducing walking EC, and improving gait biomechanics and walking speed in patients with calf muscle weakness, compared to standard, non-optimised AFOs. A second aim is to build a model to predict optimal AFO stiffness. A prospective intervention study will be conducted. In total, 37 patients with calf muscle weakness who already use an AFO will be recruited. At study entry, participants will receive a new custom-made spring-like AFO of which the stiffness can be varied. For each patient, walking EC (primary outcome), gait biomechanics and walking speed (secondary outcomes) will be assessed for five stiffness configurations and the patient's own (standard) AFO. On the basis of walking EC and gait biomechanics outcomes, the optimal AFO stiffness will be determined. After wearing this optimal AFO for 3 months, walking EC, gait biomechanics and walking speed will be assessed again and compared to the standard AFO. The Medical Ethics Committee of the Academic Medical Centre in Amsterdam has approved the study protocol. The study is registered at the Dutch trial register (NTR 5170). The PROOF-AFO study is the first to compare stiffness-optimised AFOs with usual care AFOs in patients with calf muscle weakness. The results will also provide insight into factors that influence optimal AFO stiffness in these patients. The results are necessary for improving orthotic treatment and will be disseminated through international peer-reviewed journals and scientific conferences.

Waterval NF ，Nollet F ，Harlaar J ，Brehm MA ... -  《BMJ Open》

Modifying ankle foot orthosis stiffness in patients with calf muscle weakness: gait responses on group and individual level.

Waterval NFJ ，Nollet F ，Harlaar J ，Brehm MA ... -  《Journal of NeuroEngineering and Rehabilitation》

Stiffness modification of two ankle-foot orthosis types to optimize gait in individuals with non-spastic calf muscle weakness - a proof-of-concept study.

Ploeger HE ，Waterval NFJ ，Nollet F ，Bus SA ，Brehm MA ... -  《Journal of Foot and Ankle Research》

Ankle-foot orthoses that restrict dorsiflexion improve walking in polio survivors with calf muscle weakness.

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.

Ploeger HE ，Bus SA ，Brehm MA ，Nollet F ... -  《-》

Stiffness-Optimized Ankle-Foot Orthoses Improve Walking Energy Cost Compared to Conventional Orthoses in Neuromuscular Disorders: A Prospective Uncontrolled Intervention Study.

Waterval NFJ ，Brehm MA ，Altmann VC ，Koopman FS ，Den Boer JJ ，Harlaar J ，Nollet F ... -  《-》