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

Abstract

Objective In 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). Method Ten 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. Results The 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). Conclusion Mechanical work was similarly improved by the two orthoses. The Chignon ® orthosis improved the free-walking speed and the ankle's segmental kinematics.