Optimizing ankle foot orthoses in neuromuscular diseases

Ankle foot orthoses (AFOs) of which the stiffness mode-of-action is optimized will be more effective in reducing the walking effort compared to standard AFOs. The optimal AFO stiffness at which walking effort is lowest will be determined by patient characteristics regarding anthropometrics, impairments and walking speed.

The total study duration will be 48 months. The first 6 months of the study will be used to train the research investigator and to involve the participating centers; from 6 to 30 months, patients will be recruited for the study and baseline assessments will be performed; and from 9 to 36 months, the follow up measurements will be performed. The final 12 months will be used for analyses, and addressing the main research questions.

After inclusion, participants will be fitted with a new AFO. This AFO consists of a foot part, a calf casting and a replaceable carbon fiber spring. As such, stiffness of the AFO can be varied within the same orthosis. For each patient, five carbon fiber springs will be evaluated (ranging in stiffness from very flexible (K1) to very stiff (K5)), allowing the selection of the stiffness with the maximal benefit for a particular subject (i.e. with the greatest reduction in walking effort), referred to as the subject’s optimal AFO. The effect of this optimal AFO will be evaluated 12 weeks later and compared to the patients current (old) AFO.