Assessment of the Chignon® dynamic ankle–foot orthosis using instrumented gait analysis in hemiparetic adults

ObjectiveIn the hemiplegic adult, gait is frequently perturbed by lack of ankle dorsiflexion at toe-off and may prompt prescription of an ankle–foot orthosis (AFO). Our objective was to evaluate the effect on gait of a dynamic AFO (the Chignon® orthosis) in comparison with a prefabricated AFO (PAFO).MethodTen chronic hemiplegic patients performed a 10 m gait test and then underwent an instrumented treadmill gait test under three different sets of conditions (without an orthosis, with a PAFO and with a Chignon® orthosis). The energy cost was calculated by measuring the oxygen consumption during gait.ResultsThe patients’ free-walking speed was higher with the Chignon® orthosis (0.81 ± 0.25 ms−1) than without it (0.64 ± 0.25 ms−1; p < 0.001). The ankle's segmental kinematics were better with the Chignon® orthosis than without an orthosis, notably in terms of ankle position at heel strike (− 0.8° ± 4.6 versus − 7.9° ± 8.3; p = 0.009) and ankle dorsiflexion at toe-off (1.7° ± 4.6 versus − 5.5° ± 7.2; p = 0.006).External mechanical work was lower with both the PAFO (0.61 ± 0.2 J kg−1 m−1) and the Chignon® orthosis (0.61 ± 0.23 J kg−1 m−1), relative to gait without an orthosis (0.73 ± 0.25 J kg−1 m−1; p = 0.003). Total mechanical work was also lower with the PAFO (0.9 ± 0.25 J kg−1 m−1) and the Chignon® orthosis (0.87 ± 0.25 J kg−1 m−1), relative to gait without an orthosis (1.09 ± 0.37 J kg−1 m−1; p = 0.001), whereas the reduction in energy cost with orthosis use was borderline-significant (p = 0.06).ConclusionMechanical work was similarly improved by the two orthoses. The Chignon® orthosis improved the free-walking speed and the ankle's segmental kinematics.