The Unilateral Ferrari KAFO is a lower extremities orthosis with a jointed lateral upright. If the quadriceps muscles are strong enough, the thigh cuff can be made anterior and the range of motion in the knee joint free. If the thigh muscles are very weak or the knee is in flexion contracture of over 15 degrees, the knee joint will be locked and the thigh cuff will be placed on the posterior side. The unilateral KAFOis used on MMC children with leesion level of S1 to L4. The orthoses can be made from thermoplastic or laminated out of composite materials. The latter has better rotational stability.