Objective: To investigate the effects of dynamic (hinged) and solid ankle-foot orthoses (AFO) on the gait characteristics in spastic cerebral palsied children and to find out which AFO has a more beneficial effect on correcting the abnormal gait pattern in those children.

Method: The subjects were 40 children with spastic cerebral palsy (CP) who were able to walk independently without walking aids. Their ages were ranging from 2 to 12 years. Children were randomly prescribed to dynamic or to solid AFO. Twenty-four children got solid AFO and 16 children got hinged AFO. Gait characteristics were evaluated by computer based kinematic gait analysis while they were walking with AFO and on barefoot. Gait characteristics on barefoot and with hinged AFO and with solid AFO respectively were compared.

Results: Temporospatial parameters while walking on barefoot were not significantly different from those while walking with AFOs. While walking with hinged AFO, the maximal knee extension angle during stance phase was decreased in comparison with that on barefoot (p＜0.05). Ankle dorsiflexion angle on hinged AFO was increased throughout the gait cycle (p＜0.05). While walking with solid AFO, ankle dorsiflexion angle at initial contact, at 98% of gait cycle and at maximal ankle dorsiflexion angle in stance phase were increased in comparison with that on barefoot (p＜0.05). There was no significant difference of changes after wearing orthoses between hinged and solid AFO.

Conclusion: Both types of AFOs exerted a positive effect on ankle motion, not in knee or hip joints in the children with spastic cerebral palsy. The gait characteristics during walking with both AFOs were not significantly different, even if the hinged type might be more effective in preventing knee hyperextension in stance phase and in improving maximal ankle dorsiflexion during the swing phase.

Hemiplegic gait is characterized by slow and poorly coordinated movements of the affected limb resulting from foot drop or equinus deformities. Ankle-foot orthoses(AFO) are frequently prescribed to improve the gait pattern of hemiplegics. Plastic AFO with different trimlines in controlling ankle motion can cause variable biomechanical effects.

In this study, we analysed the biomechanical effect of donning AFO on hemiplegic gait and assessed whether any differences resulted when the AFO was modified. Gait events, plantar pressure, foot contact and centers of pressure(COP) parameters were measured with F-scan pressure sensitive insole system in 21 hemiplegic stroke patients with Brunnstrom's lower extremity stage 3. And those parameters were compaired in each of four different conditions: 1) before donning AFO, 2) donning AFO without any modification, 3) donning AFO with the distal part of metatarsal head trimmed off, 4) donning AFO with third condition and weaning a cushioned heel shoes.

After donning AFO, total contact area and contact width were increased, and initial contact COP and mean COP were displaced medially. But contact length was not changed and initial contact COP and mean COP were not displaced anteroposteriorly. Anteroposterior displacement of COP, slope and velocity of COP were not also changed after donning AFO. Among various AFO adjustments, there were no significant changes of plantar pressure, foot contact and COP parameters.

The results suggest that 1) AFO provides mediolateral stability, but does not provide additional functional rocker actions during stance phase and 2) There were no definite different biomechanical actions among various adjustments of plastic AFO in hemiplegic gait of Brunnstrom's lower extremity stage 3.