Here I am, stiff-legged, walking towards the camera. On my right leg, I am wearing a knee.ankle-foot orthose, or orthosis, known as a KAFO. Its purpose is, in my case, to keep my knee and ankle from moving too far from side to side. Knees are not supposed to be able to move from side to side at all. Ankles are supposed to be able to move from side to side within a certain distance, otherwise our ancestors would not have been able to traverse uneven ground on the African plains where we evolved. But after suffering several twisted ankles, my ankles are such that I could almost walk on them unless they were held firm by sturdy high-ankle boots, which I wear to work. During leisure hours, I replace them with my exo-skeletal steel legs. In the photo, my left leg is controlled by a full length kafo even longer than the one on the left. It reaches to within 1½" of my crotch and provides a comfortable security along my entire leg. I no longer need to watch carefully where I am placing my feet, especially on uneven surfaces such as cobble stones, but I can stride ahead with confidence knowing that my knees and ankles are secure from injury.
