In looking at children with cerebral palsy and assistive devices, the Gross Motor Function Classification System (GMFCS) is a good predictor of the amount of assistance required both in physical assistance and in assistive devices with children at higher levels requiring more devices or personal help, especially at levels IV and V.
Orthoses/Braces
Orthoses (braces) are used for many children with cerebral palsy. They are used for hands, feet and for the trunk. Basically, there are two reasons for using them: positioning and enhancing function.
Ankle/Foot Orthoses (AFO)
Orthoses for the foot and leg can be divided into four types. The first type controls the heel and foot position; these basically keep the feet from rolling over to the inside or to the outside and keep the ankle in the middle. These braces do not have a direct impact on keeping the foot down, for example in toe walking, nor do they have any impact on the knee. The two kinds are called supramalleolar (SMO) or submalleolar, also called UCBL (University of California at Berkeley Laboratory). Braces are generally named for the joints they cross; the malleolus is the name of the ankle bone on the inside and outside. Therefore, a supramalleolar brace or SMO goes just above the ankle, so it keeps the foot from rolling in or out but allows any movement that the child is able to do at the ankle up or down, (dorsiflexion or plantarflexion). The submalleolar then is below the ankle bone and helps keep good foot position in those who have a slight tendency to roll inward on the ankle.
The next group of braces (AFOs) is used for leg control at the ankle for dorsiflexion (bending up) or plantarflexion (bending down) of the foot with no moving parts. These give excellent positioning of the foot and ankle and do not allow toe walking. They also minimize the tendency for back kneeing, also called hyperextension of the knee or genu recurvatum. The leaf-spring AFO allows minimal plantarflexion and has no joint. The back of the brace is cut out. Both of these braces allow someone to walk and clear the floor without dragging their foot or toes. It keeps excellent positioning of the feet and ankles.
The third group of leg braces limits plantarflexion of the ankle but has a joint (articulation) that allows dorsiflexion of the foot. These allow a more natural flow in walking for those whose tone is not so severe that it does not overpower the brace. These have a joint at the ankle, which allows movement into dorsiflexion while limiting the plantarflexion and keeping good positioning of the feet. These are used for children with toe walking as well as knee hyperextension. These do not work for children who have a crouched gait pattern [walking with flexion (excessive bending) at the hips and knees].
For those children with a crouched gait, the fourth group of leg braces provides excellent positioning. These are called ground-reaction orthoses or floor-reaction orthoses (GRAFOs). These allow good control of the positioning at the ankle as well as good positioning at the knee and helps push the body into a more extended or straightened-up position. This is good for those with crouched gait or with weakness of the quadriceps, the muscle at the front of the thigh that straightens up the knee. There must be good range of motion at the knee to allow this to be effective; it will just cause a loss of balance if there is flexion contracture at the knee, and there must be some ankle strength. Additionally, this will not be effective in those who have crouching due to hypertonicity or increased muscle tone.
