To limit hip and knee movement, this device is worn from the waist to foot. Usually, it is connected at the waist and controls both legs for instability. The HKAFO provides maximum stability at the hip, knee, foot and ankle complex. It can be fabricated from plastic, carbon composites, hybrid variations, leather and metal. Various styles of hip, knee,and ankle joints are available as per patient presentation and diagnosis. The HKAFO is used for a number of conditions like muscular imbalance and/or weakness, paralysis (spinal cord injury, spina bifida, myelomeningocele), cerebral palsy, muscular dystrophy, Polio and MS.

A reciprocating gait orthosis (RGO) is also a HKAFO however it allows one leg to be placed ahead of another - more like normal walking. This is achieved by linking the two KAFOs together by a band, two cables or a push-pull rod which transfers movement energy from one leg to the other (see diagram). Therefore as one leg is flexed or brought forward, it causes a reciprocal extension of the other leg. This allows a much smoother gait and greatly reduces the amount of effort that is needed to walk. A walker can often be abandoned for forearm crutches.

The RGO is commonly used for individuals with a lesion level of T12 to L3 (although higher levels are possible) who lack adequate strength to maintain hip extension. Good upper extremity strength, high motivation levels, good family support and minimal contractures definitely contribute to the successful use of the device.