In praise of the mighty AFO (Ankle Foot Orthosis)
(AFOs or short leg braces)
by Dr. Robert Sampson, U.S.A. (June 1997)

Foot braces or orthotics cushion and support the sole of the foot. They also make up the foundation for leg braces. Short leg braces usually go from the upper calf to below the sole of the foot. They are often referred to as AFOs.
One exception is the UCB insert. This is an orthotic that comes almost up to the level of the ankle, but not up the calf. UCB stands for University of California at Berkeley where is was developed. It is also referred to as the UCBL and the L stands for biomechanical Laboratory. This device gives more support than a regular orthotic, but less than a true AFO. It is very difficult to fabricate and requires an expert orthotist.

The classic form of an AFO is a lightweight plastic device that is usually made of polypropylene. However, many types of plastic and fibreglass laminates may be used. Most weigh about six ounces and have a strap just below the knee. The strap is usually made of Velcro, but may be leather. The bottom of the AFO fits into the shoe and is held on by the shoe. A sock is mandatory to prevent excessive sweating. Some of the AFOs are lined with a soft foam and others are perforated to let in cooling air.

The AFO usually provides a flexible springy uplift for the foot. Many people with CMtT tend to have tight heel cords or weak motors that lift the foot and ankle up (this is called dorsiflexion). An AFO will support those weak dorsiflexors and may correct a "drop foot." (An AFO cannot force the ankle up if it is stuck or contracted down.) Physiotherapy or surgery must first correct any fixed contracture before the AFO can be of much benefit.

A properly fit AFO may not only support a droopy foot but also one that is tilted sideways…as long as the tilt is flexible.

A T-strap or molded foam insert may be necessary at the ankle if there is a lot of swing or sway. Doctors call the side to side deformity valgus or varus.

There are a number of special AFOs that vary in configuration and they may hold the foot in a position that will force the knee or hip to react in a certain way. Some of these AFOs spiral around the calf or tip in a particular direction.

Older AFOs were called upright braces. These usually had heavy, but sturdy, steel supports coming up either side of the calf. Usually these were actually fastened to the shoe and the shoe was an integral part of the brace. These were quite heavy and were hard to put on and take off. Upright braces are also noisy and I try hard to get all my patients out of these heavy weights and into plastic.

The plastic AFOs may be hinged (articulated) or non-hinged. Most are not hinged and rely on the plastic "memory" to provide springiness. Hinges, when present, may be adjusted to any desired range of motion and may be given various degrees of lifting force. The brace maker (orthotist) has at his disposal many types of hinges to install.

In the U.S. and Canada, most AFOs are custom made and although expensive, about $400-$500 or more, are worth the customizing. Off-the-shelf AFOs run about $30-$40 and are okay for those lucky enough to find them comfortable or who know how to heat mold them.

There are several other types of AFOs that are of interest. These are the prefabricated springy wire or "coat hanger wire" orthoses. They are usually ordered through an orthotist or physician. They cost about $35-$50 and provide uplift for a flexible drop foot but offer very little support for a wobbly ankle. They are very light weight, have a calf strap, and clip onto the shoe or insert into the shoe without usually requiring a shoe modification. Some are actually fastened to the heel by a stirrup.

So, in summary, for weak or deformed ankles: 1) If it is a fixed deformity, get it fixed before getting it braced; 2) For a flexible deformity, an AFO is a good choice; 3) Try to keep the AFO as light as possible; 4) Never accept an uncomfortable brace…insist on comfort or you will end up not wearing it; 5) If bracing fails, then consider surgery, either a stabilization or a fusion.