With each step the foot is placed against the floor and the brace put pressure against the shin bone or tibia. The tibia is forced back, supporting the knee. Knee braces are used to control flexion and extension of the knee and to control side way movement. They are frequently attached to an AFO and extend to the thigh. Moving proximally the hip can be included in the brace to prevent deformity and to realign the legs when the child does not have adequate neurological or muscle control.
Various joints are available here as well as at the knee and the ankle.
The RGOs or reciprocal-gait orthoses is used when the child has hip flexors and no hip extensors to pull the leg back. That is, the child can bring the leg forward but does not have any muscles to return the leg to a position of support of the upper trunk. As the child steps forward with the leg, the opposite leg is pulled backward which pushes the body forward. Moving up into the trunk are braces to support the spine. They are used to try and prevent or control deformities such as scoliosis and kyphosis.