Dr. Ian H. Beiser's Podiatry Page
Orthotic devices or orthoses are shoe inserts that are intended to correct an abnormal or irregular walking pattern. Some people refer to orthotics as arch supports but they are really more than that. Arch supports are simply over-the- counter devices that provide some cushioning under the arch area. Orthotics are typically custom molded devices that are designed to control and improve the foot function of an individual. A simple analogy that helps to clarify the difference between a custom molded orthotic and an arch support would be the difference between a pair of off-the-shelf sunglasses and a prescription pair of sunglasses. While both the over-the-counter sunglasses and over-the-counter arch supports may help to provide a simple function, the prescription eyeglasses and prescription orthotics are tailored to help the individual's eyes and feet respectively, to function better. One should be aware of some instances in which over-the-counter arch supports are marketed as "orthotics". One may also encounter pre-fabricated "orthotics". While the word "Orthotic" may be prominently displayed in the packaging of these products, one should be aware that these are not the same as custom molded orthotics but rather are really not much different than products labeled as arch supports. In order for a Custom molded orthotic to be made, an impression of the individual's feet must be obtained. This can be done with plaster, foam or by scanning into a computer.
Orthoses are designed to improve foot function and minimize stress forces. There are different categories of orthotics and many different materials from which to choose. They may be rigid, semi-rigid or soft. Rigid orthoses provide functional control. Soft (accommodative) orthoses help to absorb shock and take pressure off sore spots. Semi-rigid devices provide a dynamic balance and are often used to aid athletes. Sometimes extensions can be added to a functional orthotic shell to create an orthotic device that has both a rigid or semi-rigid functional shell with a soft, accommodative topcover or extension.
Accommodative orthotics are usually made of soft materials such as leather and various types of foam. Some common materials include Plastizote, PPT and Spenco. These are often prescribed to treat conditions such as metatarsalgia and plantar keratoses or I.P.K.s (corns or calluses on the bottom of the foot.) In these conditions, there is either uneven weight distribution or loss of the normal fat pad cushion on the bottom of the foot. They are also commonly used in the shoes of diabetics, particularly those with peripheral neuropathy, who are at risk of developing foot ulcers. When one or more bones are even just slightly out of proper alignment, some of the bones at the ball of the foot bear too much weight and become more likely to develop calluses, ulcers or pain beneath them. Accommodative orthotics help to rebalance and reduce weightbearing pressure on the bottom of the foot.
Functional orthotics are usually made of materials that are rigid or semi-rigid. Common materials include plastics such as polypropylene (semi-rigid) and Rohadur (rigid). Stainless steel has been used historically but is rarely used today due to the availability of better, more adaptable and easier to use materials. Other common materials used today include fiberglass composites which may range in density from flexible to semi-flexible to semi-rigid. The most common reason functional orthoses are prescribed is to control pronation. Excessive pronation may contribute to the development of heel pain/ plantar fasciitis, tendonitis or arthritic conditions associated with flat feet, hallux valgus/bunions and hammertoes.
There are several components to the functional orthotic. The most obvious is the shell. This is the form-fitted piece that sits beneath the heel and arch. It usually ends just behind the ball of the foot. The shell cradles the bottom of the foot and supports the arch. Although the material is made of a firm material such as plastic or fiberglass, it is usually very comfortable because it spreads weight evenly along the bottom of the foot.
Another component is the rearfoot post. The rearfoot post is used to tilt the entire foot slightly in a desired direction. For example the foot is often posted so that it is inverted (inner side of the foot tilted up) about 4 degrees. Doing this, alters the position of the joints in the rearfoot and midfoot and reduces the amount of pronation (flattening of the arch) that can occur.
There is also a forefoot post. This is often built directly into the shell and balances the front of the foot with the back of the foot. For example, if the front of the foot (forefoot) is tilted relative to the back of the foot (rearfoot), the foot is forced to roll in excessively while walking. A forefoot post corrects any imbalance and eliminates the need for the foot to pronate excessively.
An extension is optional. This is a piece that extends from he shell to the toes or just behind the toes. It is usually made of a soft, foam-like material.The extension may be modified to accommodate painful area beneath the ball of the foot such as a painful callus or metatarsalgia. It can also be used to simply provide some cushioning as a replacement for the innersole of an athletic shoe.
The topcover is a piece of material such as vinyl or leather that covers the entire orthotic. Sometimes it is purely cosmetic and some orthotics are made without topcovers.
There are also many other modifications that may be prescribed. Examples of common modifications are a Schaeffer plate which is a widening at the arch portion of the orthotic shell. This helps to provide better control in very flexible flat feet. Another example of a modification that may help to provide more stability is a deeper heel seat.
The classic, full sized orthotic or sport orthotic will usually fit well in most lace up shoes. For men who often wear either an athletic shoe, walking shoe, boot or oxford style dress shoe, the full sized orthotic is ideal. It can be switched from shoe to shoe without difficulty. Orthotics can also be made less bulky to fit more comfortably in dressier women's shoes. The orthotic can be made with an intrinsic rather than extrinsic rearfoot post (i.e. no visible heel lift on the orthotic) so as to fit more comfortably in women's low heeled dress shoes, typically pumps less than 1 1/2", or men's loafers. Special orthotics can also be made to fit in pumps greater than 1 1/2 inches.
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