Conservative Treatment of the Foot

General Considerations

Conservative treatment of foot and ankle disorders is important and often successful. Nonoperative regimens are relatively inexpensive and can be easily accomplished. The treating physician and surgeon should have thorough knowledge and understanding of the interaction of the foot and the shoe or device applied. Also, the biomechanics of normal foot function and the effect of the disease entity being treated should be analyzed. The anatomy of the normal shoe, the function of each component, and the effect of modifying each of these components must be appreciated.4,5,7,23,24 Furthermore, the practitioner should be familiar with over-the-counter devices as well as with prescribed inserts and orthoses. The desired results of these devices on the foot and ankle should be fully recognized.^8,15

The majority of adult forefoot deformities are acquired and the result of ill-fitting footwear. The most common of these deformities are hallux valgus, hammer toes, hard corns, interdigital neuromas, and plantar keratoses.

The foremost component of conservative treatment begins with patient education about the effects of ill-fitting shoes and high heels. Forefoot loading is increased by the foot sliding forward into the toe box.²² Female patients may not comply with this initial treatment because ill-fitting shoes continue to be inherent in high fashion. It is often necessary to remind patients that, for daily dress, there is no other part of the body they would consider putting in a container whose shape is so drastically different from that body part. A useful tool is comparing an outline of the patient’s foot to his or her current footwear; this is usually effective in conveying this point (Fig. 4-1). Unless the patient is willing to accept that a change in footwear is indicated, both conservative and operative intervention may be futile.

Figure 4-1 Comparing the outline of a foot to a woman’s dress shoe demonstrates the disparity in shape.

A proper-fitting shoe should accommodate the variations in the person’s foot.¹⁶ A set of consumer guidelines has been developed by the National Shoe Retailers Association, the Pedorthic Footwear Association, and the American Orthopaedic Foot and Ankle Society (Table 4-1). It is imperative to measure the shoe with the foot in a standing position because the width of the foot can increase up to two sizes and length by one-half size from the sitting to standing position. In addition, the foot should be measured late in the day because the foot expands in volume as much as 4% by the end of the day. Shoes should be fitted with the normally worn socks. There should be a full finger breadth between the tip of the shoe and the end of the longest toe, with the toes fully extended.

Table 4-1

10 Points of Proper Shoe Fit

1. Sizes vary among shoe brands and styles. Do not select shoes by the size marked inside the shoe. Judge the shoe by how it fits on your foot.

2. Select a shoe that conforms as nearly as possible to the shape of your foot.

3. Have your feet measured regularly. The size of your feet changes as you grow older.

4. Have both feet measured. For most persons, one foot is larger than the other. Fit to the larger foot.

5. Fit at the end of the day when the feet are largest.

6. Stand during the fitting process and check that there is adequate space ( to inch) for your longest toe at the end of each shoe.

7. Make sure the ball of your foot fits snugly into the widest part of the shoe.

8. Do not purchase shoes that feel too tight, expecting them to stretch.

9. Your heel should fit comfortably in the shoe with a minimum amount of slippage.

10. Walk in the shoe to make sure it fits and feels right.

National Shoe Retailers Association, the Pedorthic Footwear Association, and the American Orthopedic Foot and Ankle Society: 10 Points of Proper Shoe Fit. Columbia, Md, National Shoe Retailers Association, 1995.

Recently, walking- and running-type athletic shoes have made proper-fitting shoes more socially acceptable. Currently, women have more choices in the appropriate and acceptable type of footwear in many workplace environments. Acceptance of proper fit over trends in style may adequately relieve a patient’s symptoms.

Modification of footwear or use of orthoses can be used to treat deformities of the foot. Disease can compromise motor function, joint function, skin integrity, sensation, and proprioception. Once the effects have been assessed, the appropriate modifications should be prescribed to attempt to restore normal function or protect the affected limb from further breakdown.

Foot Orthoses

Foot orthoses are devices that can be placed in a shoe to help accommodate deformities or to decrease abnormal pressure or stress at a specific site on the foot or ankle. Orthoses function by applying a force on the body in a controlled manner to achieve a desired result, that is, transfer of pressure or restriction of motion. These devices range from simple shoe insoles to ankle–foot orthoses (AFOs). The popularity of shoe inserts for runners has led to many anecdotal claims about the efficacy of their use. However, there are few controlled studies to confirm these claims.

It should be remembered that although orthoses may correct foot position and accommodate deformity, there is no evidence that an orthosis can correct or prevent the development of a hallux valgus or other structural deformities. Also, these devices may not prevent knee, hip, or back arthritis. The goals of foot orthoses include providing shock absorption, cushioning tender areas of the foot, relieving high plantar pressure areas by redistributing weight-bearing pressures covering the entire plantar surface, supporting and protecting healed fracture using the total-contact concept, controlling and supporting flexible deformities, limiting motion of joints, and accommodating fixed deformities with soft moldable materials.¹⁷

It is not always necessary to use a custom orthosis. For the accommodation of many forefoot- and heel-related problems, over-the-counter inserts may be effective in relieving symptoms, and at a lower cost. The abuse and overprescribing of custom inserts has led most medical insurance companies to deny payment for these inserts. Familiarity with the over-the-counter devices allows the treating physician to direct the patient on how to use these devices efficaciously and may be useful for initial treatment.

Over-the-Counter Inserts

With the advances in materials used in shoe manufacturing, it is often possible to accomplish many of the goals of orthosis without the expense of custom-molded inlays. Several companies offer padded insoles for shock absorption and heel cushioning (Fig. 4-2). Spenco, Viscopeds, Dr. Scholl’s, and other companies provide padded insoles and inlays that can provide relief for metatarsalgia and fat-pad atrophy. The addition of metatarsal supports, such as the Hapad longitudinal metatarsal pad on a cushioned inlay or in a shoe with a soft sole, can effectively relieve metatarsalgia or neuroma symptoms. Various heel inserts, such as Visco heels or Tuli heel cups, are often helpful in treating plantar heel pain. These devices are readily available through medical supply catalogs and are often found in pharmacies and athletic shoe stores. Patients should be educated on their proper placement and use.

Figure 4-2 Over-the-counter inserts. A, Viscoped. B, Combination liner and Hapad metatarsal pad. C, Visco heel cushion. D, Full-length insole. E, Three-quarter–length insole.

Once the patient has been evaluated and the desired correction chosen, the proper footwear should be selected. In some instances, this may be all that is needed. If additional correction is needed, off-the-shelf items should be considered. The cost to the patient is considerable for custom orthoses, and more insurance companies now refuse payment for any orthosis that does not cross the ankle joint. If adequate correction cannot be accomplished, custom orthoses can be prescribed.

Custom Foot Orthoses

If the patient has a deformity or disorder that is not amenable to treatment with an over-the-counter device, a custom orthoses may be appropriate. There are three general types of custom inserts: soft, semirigid, and rigid (Fig. 4-3).

Figure 4-3 Common types of custom orthoses. A, Plastazote insole, a soft material ideal for patients with rheumatoid arthritis or diabetes mellitus. B, Full-length orthosis with relief for the first metatarsal head, such as for sesamoiditis. C, Three-quarter–length foot orthosis indicated for hindfoot disorders. D, Rigid foot orthosis. E, Morton carbon fiber plate used for turf toe or hallux rigidus.

Soft orthoses are made with materials that may include polyurethane foam, polyvinyl chloride foam, ethylene vinyl acetate, and latex foam. These materials are used when the effect is cushioning, impact absorption, and reducing shear forces of friction. This is particularly important for use in the insensate foot. Also, soft inserts are beneficial for use with fixed deformities, especially those with bony prominences. Soft materials can be used with semirigid material underneath to gain better mechanical properties. These inserts are generally thicker than the rigid orthoses and may require the use of an extra-depth shoe, depending on the pathology.

Semirigid orthoses are the most commonly prescribed inserts. Unlike rigid orthoses, they offer shock absorption and some flexibility while still providing tensile strength and durability. They are used to support and stabilize flexible deformities and relieve pressure by weight transfer. Combinations of materials are often used; the inserts are generally thicker than rigid inserts and might require the patient to wear a deeper shoe. The materials used include leather, polyethylene compounds, closed or open cellular rubber compounds, cork, felt, and viscoelastic polymers.

Rigid orthoses are used to decrease or control motion, such as in the treatment of arthritis of the midfoot or forefoot. The device stiffens the shoe and functions similar to a steel shank within the shoe. Of note, patients with plantar prominences or significant fat-pad atrophy might find these too uncomfortable to wear. A rigid orthosis is often prescribed to block pronation but may be no more effective than a semirigid device and may be more difficult to tolerate. Furthermore, rigid orthoses offer no shock-absorbing properties and should be avoided in patients with impaired sensation. The materials used are thermoplastics or carbon fiber.

Custom orthoses are generally made from a foam impression of the feet of patients, in which the foot is pressed into the foam box evenly. The use of plantar pressure data obtained from new technology with the EMED-D pressure platform (Novel, Munich, Germany) with four sensors/cm² yields superior off-loading capacity of insoles.²⁰

University of California Biomechanics Laboratory (UCBL) Foot Orthoses

Another type of foot orthosis is the UCBL insert, which controls flexible postural deformities by controlling the hindfoot.¹⁵ The orthosis should be molded with the heel in neutral position. To work successfully, the orthosis must be able to grasp the heel and prevent it from moving into valgus. By keeping the calcaneus in neutral position, the orthosis stiffens the transverse tarsal joints, and pronation and forefoot abduction can be diminished. It may be necessary to add medial posting to the heel and forefoot to keep the heel out of valgus. As medial posting is added, it may be necessary to lower the medial trim line to avoid impingement on the medial malleolus.

With fxed deformities, such as arthritis of the midfoot, a UCBL insert can decrease motion and reduce pain. The foot is molded in situ, and the polypropylene should have a relief over the area of bony prominence. The orthosis can be lined with a material for pressure absorption, such as polyurethane foam (PPT) in the relief, and then the entire orthosis can be covered with a material such as polyethylene foam (Plastazote) for comfort (Fig. 4-4).

Figure 4-4 University of California Biomechanics Laboratory (UCBL) insert. A, Posterior view. B, Medial view. C, Posterior view of a patient with posterior tibial tendon dysfunction demonstrating hindfoot valgus, pes planus, and forefoot abduction. D, UCBL insert controlling foot deformity.

Ankle–Foot Orthoses

The most common type of orthosis that has proved useful in treating foot and ankle problems is the ankle–foot orthosis (AFO), made of either molded polypropylene or double-upright construction.

AFOs can be made from double uprights attached to the shoe or molded polypropylene, either as a posterior shell or incorporated into a leather lacer (Arizona brace) (Fig. 4-5). The molded AFO is more potent in most instances. The AFO can be made with a fixed or hinged ankle. The orthosis is manufactured from a positive cast of the lower limb. Modifications can be made through reliefs over bony prominences to accommodate fit, and these can be lined with material to provide comfort and protect the foot and deformity. These modifications of the orthosis allow better control of deformities and expand the use of these orthoses to rigid as well as flexible deformities.