There are innumerable shoe types and styles, although basic designs are relatively few (Fig. 76-4). The basic designs are determined mainly by the shape of the upper, particularly the design of the toe and the height of the quarters. The low-quarter shoe, also known as Oxford shoe, is characterized by the quarters finishing approximately 1 in. below the malleoli with no restriction of ankle or subtalar movement. In high-quarter shoes, the quarters may extend up to barely cover the malleoli, as in the chukka shoe, or extending to the lower third of the tibia or higher, as in boots. This style prevents piston action during walking and back-and-forth sliding of the foot. In addition, it provides some degree of medial-lateral stability at the ankle and subtalar joints, and some restriction of plantar/dorsiflexion ankle motion. The most common opening style is the blucher type, in which the lace stay is not directly fastened to the vamp. This style gives a wide opening for the foot for easy insertion and greater adjustability over the mid foot. For ease of access the surgical opening shoe allows exposure of the entire foot by opening up to the toes. The bal-type (Balmoral) throat, which has the face stay attached directly to the vamp, does not provide such easy foot access. Shoe closure usually is accomplished by cotton laces, which thread through two or more pairs of eyelets, although closure can also be achieved by buckles, zippers, Velcro flaps, or elastics.

Modifications to commercial footwear and in some instances, custom footwear are an important aspect of orthotic practice. Shoe modifications can successfully treat many simple problems that affect walking and is an integral part of any orthotic prescription (11,13).

Dozens of base materials and literally hundreds of variations of those base materials are used in the manufacture of shoes. In this section, discussion is limited to the general categories of materials found in shoes used in conjunction with orthosis and with or as corrective devices. The shoe can be
modified by adding a variety of alterations including changes to the heel, the addition of metatarsal pads, rockers, and other modifications.

Materials used in the construction of shoe soles vary greatly and have significantly different properties with regard to weight, durability, shock absorption and attenuation, flexibility, and support.

Leather soles are extremely durable and once it was the choice soling material but now it is reserved primarily for high-end dress shoes. Leather tends to be stiff and heavy, and offers little or no shock absorption when compared to other materials and can be slippery in wet conditions. Leather soles do allow for relatively simple attachment of AFOs.

Hard rubber is a great alternative to leather, especially when used to attach an AFO as it has some degree of impact absorption at heel strike and it is less slippery when used to walk in wet environments. Crepe is a cellular rubber compound that typically offers a great combination of shock absorption and traction. A shoe with a crepe sole can still have an AFO attached to it, although it is not as easy as with a leather or rubber-soled shoe to fabricate. Crepe is the most commonly used material for shoe modifications.

Vibram® is a dense microcellular rubber. It has many qualities of crepe but is more durable and can be more shock absorbing. This material can also be used with a shoe in the construction of an AFO.

Ethylene vinyl acetate (EVA) is a more recent introduction in the industrial manufacture of most types of shoe. It is shock absorbing, moldable, lightweight, and flexible and can have a multitude of colors. Sometimes this material can be difficult to use in AFO fabrication due to lack of adherence to commonly used cements. In recent years athletic shoes (Fig. 76-5A) have changed dramatically in design and materials used in their fabrication. Different sports may require different design features for optimal performance and comfort. The sole of a good athletic shoe is stiff at the heel and at the shank but very flexible at the fore foot, where it should bend easily at the ball. The outer sole usually is made of highly durable rubber compounds that provide a good grip on the ground, whereas the inner sole is designed to closely fit the contours of the foot. Between the outer and inner soles, fluid, gel or cavitated materials are placed for cushioning and shock dampening. The outer sole is often designed to flare out laterally at the heel and towards the mid foot to improve the mediolateral stability at the ankle and to ensure the foot is flat as it strikes the ground in the normal, slightly supinated position. Rising up from the rear sole to a height of approximately 0.5 in. (1.2 cm) is a heel cup, which further increases mediolateral control and provides hind foot stability. The rigid and non-compressible heel counter provides added ankle and foot stability, but for athletes with a tendency for recurrent ankle sprains, there is the option of using high-top shoes. The upper is reinforced in the mid foot area for maximum stability and to resist excessive side-to-side motion. Such reinforcement is obtained by adding stiffening bands, stabilizing lacing systems, or motion control straps.

Due to their natural increase in coefficient of friction, rubber soles have more traction than leather shoes when walking on carpeted or dry surfaces. Sometimes it is desirable to reduce friction, and application of an external leather toe slider covering the front 1/3 of the sole can be of great benefit to facilitate limb advancement when limb clearance is impaired.

The first requirement of a shoe is that it fits and does not cause pain, skin problems, or deformities. Ideally both feet should be measured in length and width, and the shoes tried on both feet in case of size discrepancy, in which case the shoe size should be chosen to comfortably fit the larger foot while some filling material may be used in the smaller one. If more than a one size difference exist, using split size shoes is encouraged (14,15). Footwear preferably should be purchased at the end of the day, when the feet often are slightly swollen. When shoes are fitted, each shoe should be judged individually in a fully weight-bearing position. The shoe should fit snugly enough not to fall off but be loose enough to adapt to the size and shape of the foot,
which changes with climate, ambient temperature, time of day, body position, and standing weight bearing. Because the foot changes shape with weight bearing and some pathological conditions, shoes initially should be carefully tested for fit, both in length and width, not only by standing but by walking for several steps and stopping fast. In length, the shoes should extend at least a half-inch (1.2 cm) beyond the longest toe, usually the hallux or the second toe. The heel-to-ball distance of the foot and the shoe should be equal. Thus, the first metatarsal joint should be located at the inner curve of the shoe, and on toe dorsiflexion, the shoe should bend easily at the toe break that should run directly across the ball of the foot. The widest part of the shoe should coincide with the broadest part of the foot, leaving enough free space medial and lateral to the heads of the first and fifth metatarsal bones, respectively. The shoe widths measured at the ball are available in different sizes, ranging from A (narrow) to E (wide). Each size represents a 0.25-in. (0.6 cm) increase in width.

The transverse arch of the foot should function normally, weight should be evenly distributed, and no sliding of the fore foot within the shoe should occur. There should be no gap between medial and lateral quarters and the heel counter should close around the heel bone without bulges, allowing only a small amount of pistoning. The height of the quarters should be sufficient to hold the shoe securely on the foot. Some pistoning usually is unavoidable in a modified shoe with a rigid sole and heel counter. The height of the vamp should be adequate to prevent pressure or irritation over the toes and the instep. If the material is soft and pliable it should be possible to fold some material from the top of the toe box to confirm appropriate space for the toes. Shoes are not usually fabricated in different depths, although extra-depth shoes and shoes with removable insoles are available to accommodate foot abnormalities and shoe inserts. The real proof of fit, however, is if the shoe is comfortable after hours of continuous wear or walking.

If there is a pathological condition with loss of sensation in the feet, new shoes should be worn using a gradually increasing schedule starting at 2 hours/day only, after which shoes and socks should be removed and the feet carefully inspected. Before donning, each shoe should be carefully inspected visually or with the hand for irregularities or foreign objects on the inside, which could injure the foot.

Stock shoes may require minor or major modifications by various methods to support the abnormal foot during weight bearing, to reduce pressure on painful areas, and to limit motion or accommodate deformed, weak, unstable, or painful joints. For these purposes, the clinician may select a special type of shoe, order certain alterations in the construction of the shoe, or apply corrections directly to the foot. For this approach to be effective, the clinician needs to make an accurate diagnosis of the problem, have a clear understanding of why corrections are needed, and write a specific prescription that is best accompanied by a simple drawing to clarify the request (Fig. 76-5B). Although certain simple external modifications may be applied easily to many types of commercial shoes, welt shoes are more suitable to work with, especially for major internal modifications, because the process of removing and reattaching the sole to the upper does usually not alter the structure of the shoe.