Bruce S. Lebowitz
The primary care practitioner is often called upon to treat patients who complain of problems with their feet. Although disorders of the feet are not life threatening, they should not be taken lightly. Any patient with a painful foot attests that the pain takes the joy out of living.
Structure and Function
The abnormal foot cannot be understood unless the structure of the foot and its function during gait are understood.
Normal Gait
The bones and joints of the feet facilitate walking and running in an upright position (Fig. 73.1). The foot and leg function together to allow a smooth, even transfer of weight as one extremity moves ahead of the other. During gait, the foot first adjusts to a variable terrain and then acts to propel the body's weight forward.
In the first stage of gait, the heel strikes the ground and body weight begins to move distally over the lateral aspect of the foot. The foot is in a pronated position, meaning that the arch is flattened. In effect, the foot resembles a loose bag of bones during this stage, permitting it to adapt to the terrain and to act as a shock absorber when body weight strikes the ground.
In the second stage of gait, as weight moves distally to the ball of the foot and the body is propelled forward, the foot must convert to a rigid lever. This conversion, or supination, takes place in the subtalar and midtarsal joints. Supination serves to heighten the arch, pushing the bones and joints of the foot together rigidly enough to propel body weight forward efficiently.
For the lower extremity to function normally, certain structural criteria must be met; if they are not met, compensation occurs. Ideally, the leg should be in a plane perpendicular to the foot and ground, as in a stick figure drawing. The forefoot should be in a plane parallel to the rear foot, but various congenital factors may act to prevent this normal angulation. Varus (toward the midline or inverted) or valgus (away from the midline or everted) positions of the forefoot or hindfoot are the most common of these congenital factors.
Excessive Pronation
Excessive pronation (pronation extended through too much of the gait cycle) is the most common compensating mechanism when structural abnormalities are present. When the foot remains pronated during gait and does not resupinate in time, or at all, the condition known asflatfoot exists. The degree of this flatfoot position reflects the degree of pronation that is present. A number of problems may evolve from excessive pronation during gait, including bunions, calluses, and hammertoes. As pointed out in the discussion that follows, assessment of the mechanical basis for the condition is important in planning appropriate treatment for it.
Shoes
Shoes clearly play a role in the way feet function. Shoes protect feet from the elements, cushion the effect of walking on hard flat surfaces, and provide some support to the bones and ligaments. Unfortunately, many people favor short narrow shoes, high heels, and pointed toes. Obviously, squeezing a basically rectangular foot into a
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triangular shoe with the heels elevated from 2 to 5 inches creates significant stress for the foot. Most of the disorders of the foot discussed in this chapter are intensified by these demands of fashion.
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FIGURE 73.1. A: Schematic representation of the gait cycle for a normal foot and for a foot with excessive pronation. B: Schematic illustration of foot structure during pronation and supination during gait cycle. |
Most people, in fitting themselves for shoes, do not take into account the variations in their foot size throughout the day and the variation in shoe size from manufacturer to manufacturer. Therefore, the following advice often is helpful: buy shoes in the late afternoon when any swelling that might occur is already present; lightweight shoes are preferable to heavy shoes; and leather, because it is more porous, is preferable to synthetic materials in shoe construction.
Interest in shoes appropriate to sports, especially jogging and running, has escalated in recent years. Sneakers or running shoes should be well fitted and firm enough to prevent excessive splaying of the foot during activity. For shock absorption, the shoes should have studded soles, and there should be a raised resilient heel wedge. The midsole should be flexible to help prevent Achilles tendon stress, and there should be a well-molded Achilles pad to prevent irritation of the tendon. The tongue should be well padded to prevent irritation of the dorsum of the foot. Figure 73.2 illustrates these features.
It is a misconception that wearing sneakers excessively harms the feet. Actually, the better running shoes available today are so supportive and so well padded that they can be recommended to patients for numerous painful foot conditions. For example, highly arched feet (which are supinated and may pronate only slightly) lack shock-absorbing qualities; constant impact on the ground can cause severe metatarsal, heel, and arch pain. For patients with this condition, the support and resiliency provided by a modern running shoe are ideal. Likewise, a flat or pronated foot may be very well supported by the built-in arch supports of well-made running shoes.
Running magnifies the problems associated with excessive pronation, and the long-term management of this condition requires the selection of shoes that provide good support. The use of well-designed running shoes is important in preventing most exercise-related injuries of the lower extremity.
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FIGURE 73.2. Features of a well-designed running shoe. |
Preventive Foot Care for Patients With Diabetes or Arterial Insufficiency
To understand the need for professional diabetic foot care, one must consider the special devastating effect of diabetes mellitus on the feet. The most important podiatric problem of diabetes is neuropathy (see Chapter 79). Sensory neuropathy may cause burning and sometimes unbearable pain in the feet and legs, especially at night. At the same time, sensory neuropathy lessens the ability of the patient to interpret and respond to painful stimuli. A foreign body that is not felt or a thick corn or callus that is not treated can result in irritation of the tissues with complicating infection.
Motor neuropathy causes wasting of the small muscles of the foot. Without the intrinsic muscles helping to stabilize the motions of the toes and metatarsal phalangeal joints, the tendency to form severe hammertoe and callus is greatly increased. The mechanical forces on the toes and metatarsals are increased as the ability to sense pain is reduced.
Sympathetic neuropathy leads to excessively dry skin, and the feet of a diabetic patient often are anhidrotic and at risk for secondary infection. In addition to neuropathy, the diabetic foot is affected by vascular disease. Vascular disease also occurs in many patients independent of diabetes mellitus, and the same issues apply. Arteriosclerosis is accelerated in the diabetic patient. The changes that are often seen lead to claudication and rest pain. Diabetic small-vessel disease affects the nourishment of tissues, accounting for the finding of normal pedal arterial pulses and yet severely dysvascular digits that sometimes require amputation. Chapters 79, 94, and 95 discuss the management of peripheral vascular disease and lower extremity ulcers and the consequences of diabetic vascular and neuropathic complications.
For all of these reasons, prevention and early detection of problems on the foot's surface are particularly important in patients with diabetes because they can prevent serious foot lesions (1). Prevention and early detection include patient education, routine inspection by the patient, and periodic examination by the practitioner or nurse. Examination is important because symptoms alone are poor indicators for the presence of diabetic neuropathy and because, in the presence of neuropathy, foot lesions may go undetected and progress (2). The single most important advice that can be impressed upon the patient is to look at his or her feet every day. When obesity or lack of visual
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acuity is a problem, someone else should examine the patient's feet every day. Irritations, abrasions, and calluses that usually produce pain must be identified visually when there are sensory abnormalities in the feet. Advice about selection of shoe gear (see above) should be provided routinely to patients with diabetes and vascular insufficiency. Following these procedures minimizes the risk of serious foot ulcers and infections.
These patients also should be advised not to use over-the-counter remedies for corns and ingrown toenails. Such commercial preparations include acids and tanning agents that can seriously injure the tender skin of these patients. Normal toenails should be allowed to grow past the end of the fleshy part of the toe; thick nails are best trimmed by a podiatrist, as are corns and calluses (see Calluses and Corns). Soft cotton should be worn between toes that tend to rub each other, and talcum powder should be used to prevent interdigital moisture and maceration. Lanolin should be applied to dry and thickened skin to prevent fissuring, especially common in the heels of diabetic patients with anhidrosis from sympathetic neuropathy. Prescription-strength moisturizers such as ammonium lactate cream (Lac-Hydrin 12%) are beneficial in neutralizing the drying effects of neuropathy. Tinea pedis should be treated (see Chapter 117) to prevent breaks in the skin, which could be sources of infection. In-shoe orthotics, which cushion and redistribute pressure, have been shown to be effective in preventing and treating diabetic ulcers (3).
Evaluation and management of diabetic wounds have evolved into a subspecialty of podiatry. Diabetic ulcers are a major source of infections, disability, and loss of limb and life. The costs of treating diabetic foot wounds is enormous and constantly growing (4).
Podiatrists play a special role in débridement, pressure reduction and when necessary, surgical management of diabetic foot wounds. Prevention of wounds is the ultimate goal of all foot care providers. Regular examination of the vascular, neurologic, dermatologic, and biomechanical systems of the foot is essential in identifying risk and addressing pathology. Podiatrists monitor all these systems and provide foot care to the diabetic at-risk population on a constant basis.
A final note on prevention: Patients should be encouraged to shake out their shoes before putting them on as a simple, obvious way to prevent foreign-body penetration. Patients are advised to avoid walking barefoot, to examine their feet daily, and to change shoes frequently.
Bunions
Definition and Pathogenesis
Bunion (literally turnip) is a term used to describe the collective deformities of the first metatarsophalangeal joint (Fig. 73.3). These deformities include enlargement of the medial, medial–dorsal, or dorsal aspect of the first metatarsophalangeal joint and lateral deviation of the great toe. Enlargement of the joint may consist of bone, soft tissue, or a combination of the two.
For many years, tight-fitting shoes were mistakenly considered to be the cause of bunions. It now is known that, although the pressure of tight shoes on an existing bunion can result in pain that calls attention to the problem, bunions are not caused by poorly fitted shoes. The chief cause of the deformity is a hypermobile first metatarsal bone, most often related to excessive pronation (see Structure Function). The first metatarsal and great toe, which help propel body weight forward, should be stable during the final stage of gait when a tight, rigid, bony structure is needed. The intrinsic and extrinsic musculature should help to hold the metatarsal tight at this point. When there is excessive pronation, the entire foot remains loose and unstable. One result of such laxity in this stage of gait is hypermobility of the first metatarsal and buckling of the first toe; intrinsic and extrinsic muscles cause the first metatarsal to deviate medially and the great toe to deviate laterally. The combined deformity is called hallux abductovalgus. Eventually, arthritic hypertrophy of the head of the first metatarsal bone develops.
Symptoms
The presenting complaint of a patient with a bunion is pain localized to the first metatarsophalangeal joint. Pressure of the shoe on the enlarged metatarsal head, with or without pressure on adventitious bursa, can cause pain that is severe and even disabling; pain can also result from the joint motion itself. Often, crepitus can be felt within the joint. Sometimes the patient seeks help not because of pain but because he/she is unable to wear shoes as a result of the deformity.
In evaluating a patient, the practitioner must be certain that the symptoms are a result of the bunion alone. Gout (see Chapter 76) not only may produce acute pain in the first metatarsophalangeal joint but also may aggravate a chronically painful joint. Therefore, gout should always be considered, especially in patients with bilateral bunion deformity and acute nonarticular pain in a foot.
Management
Acute symptoms caused by a bunion should be managed with rest, elimination of pressure on the bunion, soaks in warm water, and a nonsteroidal anti-inflammatory drug such as naproxen 250 to 500 mg every 8 to 12 hours (or a cyclooxygenase-2 [COX-2] nonsteroidal anti-inflammatory drug when indicated). Aspirin 600 mg every 4 to 6 hours also can be used, but the onset of action is slower.
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After the acute symptoms have subsided, the patient should be started on a program of long-term management.
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FIGURE 73.3. Appearance, orthotic compensation, and surgical repair of bunions. A: Bunion deformity. B: Bunion protected by latex shield. C: Leather orthotic arch support. D: Bunion deformity shown radiologically before (top) and after (bottom) surgical correction. |
Conservative long-term management of a bunion involves accommodating the deformity and attempting to arrest its progress. This is achieved with the use of molds and protective shields (Fig. 73.3B–C). A mold, usually called an arch support, can be made from various types of materials to accommodate the plantar aspect of the foot. Protective shields are made of latex rubber.
Full-foot molds or protective shields made by a podiatrist from a plaster impression are preferable to commercially made devices found in pharmacies and shoe stores. Commercial devices are manufactured to fit average shoe and foot sizes and do not take into account the shape of the individual patient's foot. The mold should be in place during the fitting of all new shoes. Occasionally, if the mold makes conventional shoes too tight, a specially built shoe, called an extra depth-inlay shoe, can be used. These enlarged shoes have a removable insole, for which one may substitute the patient's mold. The mold and shoes should minimize pressures against the bunion. In addition, the mold acts to reduce excessive pronation, thereby reducing the deforming forces in the forefoot.
Patients whose symptoms are not adequately controlled with conservative measures should be considered for surgery. The surgical management of a bunion must be individually planned for each patient, and in fact for each foot, to correct the specific deformity. Correction might involve resection of the bony protuberance of the first metatarsal head with or without metatarsal osteotomy for angular correction. In occasional patients with severe degenerative joint disease, surgical management involves removal of all or part of the joint and insertion of a titanium joint replacement (Fig. 73.3D). Depending on locale, referral for surgical correction of a bunion may be made to a general, orthopedic, or podiatric surgeon. (This surgery, like most podiatric surgery, is done on an ambulatory basis in most states.) A patient should expect to return to most of his or her preoperative activities within 6 to 8 weeks after surgery; the interval may be somewhat longer after bilateral surgery. A tendency for the foot to swell postoperatively may persist for many months, however. Excessive pronation, the primary cause of bunion, persists after surgery. Therefore, a major determinant of the long-term results of surgery is followup foot care with orthotic appliances such as those described above.
Care for bunions is best individualized and negotiated with the consultant because evidence from randomized controlled trials is insufficient to determine which methods of conservative, operative, or postoperative treatment are the most appropriate (5,6). Surgical complications and continuing symptoms are not uncommon (6). Surgical treatment of diabetic patients with neuropathic and vascular disease may be complicated by infection, slow healing, or failure to heal. In these patients, therefore, a conservative approach usually is preferable.
Prevention
It is possible that the annoying symptoms of bunion deformity can be prevented if the deformity is recognized early (usually in the second or third decade) and the patient is referred for conservative management by a podiatrist.
Calluses and Corns
Definition and Pathogenesis
A callus is a thickening of the epidermis as a result of chronic intermittent trauma (Fig. 73.4). When there is intermittent irritation of an area of skin, the initial response is vasodilation. This is followed by increased production of corneum and hyperkeratosis. This process is normal and protective to skin and underlying tissue. When the process continues until there is buildup of excessive or highly concentrated callus resulting in a corn, problems may develop. Skin lines may remain visible in callused tissue, but they usually do not pass through the highly concentrated center of a corn. Corns are most often located overlying the proximal interphalangeal joints of the lesser toes and centrally within plantar calluses. A number of processes not related to chronic trauma can produce focal calluses as well, namely, verruca plantaris (plantar wart), foreign-body granuloma, and porokeratosis plantaris discreta. These lesions are discussed here.
The primary cause of most symptomatic calluses is excessive pronation (see Structure and Function), not restrictive shoes or walking on unyielding surfaces. During excessive pronation, the long flexor and extensor tendons pull on the distal phalanges, the toes appear to hammer, and a retrograde force pushes down on the metatarsal heads, increasing pressure on the plantar skin. Other conditions that may promote this increased pressure are excessive supination (highly arched foot) and imbalance of the peroneal and tibial muscles caused by weakness, arthritis, or other conditions affecting one or both legs.
Symptoms
Diffuse callus usually is asymptomatic and easily controlled by the patient with pumice stones and cleansing agents readily available in pharmacies. Both calluses and corns produce pain. Thick accumulation of callus tends to cause a burning sensation in the foot. A corn located within a plantar callus gives the sensation of walking on a sharp pebble. Corns that occur dorsolaterally on fifth toes (Fig. 73.4B) often cause exquisite pain, especially with tight-fitting shoes. Such corns often have adventitious bursae associated with them and may produce symptoms of both
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bursitis and the discomfort of the corn pressing down on subcutaneous tissues.
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FIGURE 73.4. Calluses and corns. A: Typical plantar callus. B: Corn on the fifth digit. C: Orthotic device designed to shift weight from area of callus formation. (Courtesy of Max Weisfeld, DPM.) |
Although corns and calluses can cause discomfort for the average person, they can cause serious morbidity in a diabetic patient (seePreventive Foot Care for Patients with Diabetes). A discrete lesion on the foot produces constant pressure on the underlying dermis. In a diabetic patient, this pressure often results in local breakdown of tissues, ulceration, and infection. Diabetic patients have the additional medical and mechanical problem of neurotrophic joints. In patients with the tendency to develop hammertoe and plantar-flexed metatarsal heads, these changes (and the calluses and corns that accompany them) may be accelerated by the loss of normal proprioception and pain sensation of a neurotrophic joint. Corns and calluses can be a serious problem for patients with conditions other than diabetes that impair arterial circulation to the lower extremities (see Chapter 94).
Treatment
Treatment of corns and calluses depends on the location, severity, and type of lesion and on the physical condition of the patient. Occasionally, one sees patients who complain of severely painful corns and calluses. Dramatic relief may be obtained from the simple débridement of these painful lesions, using a sterile no. 10 or 15 scalpel blade. If the blade is kept nearly parallel to the skin, injury to the
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underlying healthy dermis can be avoided. Débridement of the entire callus is not necessary; any reduction in the thickness of the lesion brings relief to the patient.
Conservative long-term management of corns and calluses in the feet of otherwise healthy people requires control of the source of the problem, namely, excessive pronation. If excessive pronation is neutralized with orthotic devices (see Bunions and also Fig. 73.4C), foot function is improved, pathologic forces are decreased, and lesions may regress. Lesions that have been present for at least 1 year usually indicate that structural changes have developed in the bones and joints, with secondary histopathologic changes in the skin.
For patients whose symptoms are not controlled with conservative treatment, surgery may be helpful. A number of surgical procedures may be used to realign metatarsal heads or reduce hammertoe deformities. Often the surgical reconstruction of affected areas must be combined with control of pronation to achieve lasting resolution of symptoms. This may mean 6 to 8 weeks of convalescence (i.e., no weight-bearing for several days, then progression to partial and then full weight-bearing, usually by 6 weeks) after foot surgery and the continued use of orthotics in shoes. The result is greater foot health and comfort.
For the patient with diabetes or peripheral vascular disease, conservative treatment involves frequent débridement of the hyperkeratotic areas, padding for protection, and fabrication of molds (by a podiatrist or orthopedist) to shift weight away from problem areas and accommodate deformities (Fig. 73.4C). Extra-depth shoes are often prescribed in conjunction with such appliances. When refractory infection or ulceration occurs despite conservative management, surgical procedures can be performed to eliminate a bony prominence. Surgery may rehabilitate a bedridden patient or obviate future amputation. The risks of surgery include infection and failure to achieve the desired result; the risks must always be weighed against the desired goal. Management requires close collaboration between the patient's primary care practitioner and the consultant.
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FIGURE 73.5. Hyperkeratotic lesions not caused by chronic trauma. A: Plantar wart. B: Porokeratosis on plantar surface. (Courtesy of Max Weisfeld, DPM.) |
Other Hyperkeratotic Lesions
Other discrete hyperkeratotic lesions commonly found on the foot include verruca plantaris, porokeratosis plantaris discreta, and foreign-body granuloma. Verruca plantaris, or plantar warts, occur on the plantar aspect of the foot, usually on weight-bearing surfaces (Fig. 73.5A). They are discussed also in Chapter 117, but a brief account is provided here because of the importance of differentiating them from corns, calluses, and other hyperkeratotic lesions. Plantar warts can be asymptomatic or extremely painful. They are caused by a papilloma virus for which there is no specific treatment or prevention. Because they are benign and often resolve spontaneously, aggressive or untried therapies should be avoided.
Figure 73.5A shows a verrucous lesion. Such lesions can vary in size from 1 mm to 1 cm. The lesions can be differentiated from hyperkeratotic corns in several ways. Warts usually have rough surfaces, are painful with application of surface and lateral pressure, and bleed upon débriding because of their capillary supply. Corns usually are smooth surfaced, most painful with surface pressure, and do not bleed upon débridement. The treatment is best directed by a podiatrist because it is essential to destroy the wart without producing a scar, which itself may be permanently painful. Chapter 117 describes the treatment of warts in general.
A porokeratotic lesion is a circumscribed discrete hyperkeratotic lesion on the plantar aspect of the foot that
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develops as a result of keratin occluding a sweat duct in the skin (Fig. 73.5B). The obstruction and resultant backup create a reaction in the skin similar to a deep large corn. This lesion need not be under a weight-bearing surface. It usually is painful, and after débridement there is characteristically even more distress. Treatment by the dermatologist or podiatrist usually is by local curettage.
Foreign bodies in the plantar surface of the foot can generate a local inflammatory reaction and thus create a hyperkeratotic lesion. One of the most common offending substances is hair (animal or human). For example, a dog hair, trapped in a carpet long enough to have dried out, can penetrate the skin rather easily. This lesion, although grossly resembling a simple callus, has a small aperture (entry wound) near the center, seen upon examination with a magnifying glass. The local reaction may or may not include infection. Treatment is simple excision of the foreign body.
Nail Conditions
Only two nail conditions are commonly brought to medical attention: onychomycosis (fungal infection) and ingrown toenails, with or without concomitant inflammation (paronychia).
Onychomycosis
Causes and Findings
The typical fungal infection of a toenail begins distally at the tip of the toe and moves proximally, subungually, and through the nail plate itself (Fig. 73.6). Etiologic agents are Trichophyton mentagrophytes, Trichophyton rubrum, or Candida albicans. The fungus produces yellowish discoloration and longitudinal striations in the nails and in the epidermis. The accompanying local inflammatory reaction stimulates hyperkeratosis under the nail. This hyperkeratotic accumulation tends to lift the nail up from the epidermis, facilitating further progression of the fungus. Eventually, the nail becomes mottled brownish yellow, thickened, and powdery. Usually, these infections are asymptomatic; patients are most concerned about the appearance of their nails, the possibility of spread of infection, and sometimes the inability to wear shoes when severe thickening of the nail plate is present.
Treatment
Fungus infections of toenails are difficult to eradicate medically. Oral medications are available to treat and resolve onychomycosis. Itraconazole is effective against dermatophytes such as T. rubrum and nondermatophytes such as yeasts and molds. Terbinafine is effective against most dermatophytes. Because not all dystrophic toenails are mycotic, treatment should be based on the results of nail fungal cultures. Both drugs, terbinafine (Lamisil 250 mg) and itraconazole (Sporanox 200 mg), are taken orally once per day for 3 months. Although itraconazole is commonly prescribed as a pulsed dose for fingernail fungus, it is not approved in pulsed form for toenail fungus. (Pulsed doses refer to double dosing for 1 week followed by a 3-week respite.) Potentially serious adverse reactions include congestive heart failure (itraconazole) and hepatic toxicity (both medications). Rare incidents of leukopenia have been reported with terbinafine. White blood cell monitoring with terbinafine and liver function monitoring with both drugs are recommended. Ciclopirox (8% Penlac nail lacquer) is an effective topical antifungal available by prescription. Although it is not as effective as the oral medications, it requires no medical monitoring. Another effective topical agent, amorolfine (5% Loceryl nail lacquer), has not yet been approved for use in the United States.
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FIGURE 73.6. Mycotic toenail. |
When nail thickening is regarded as a problem by the patient, the process can be controlled by regular and thorough débridement. The débridement of mycotic or otherwise thickened toenails is a process generally performed by podiatrists. The débridement first involves soaking of the feet and cutting of the nails by heavy-duty cutters. The nails are thoroughly filed down with an electrically powered diamond-studded burr. These drills are fitted with vacuum extraction systems to protect the patient and podiatrist from breathing in the nail dust.
Another treatment is permanent removal of the nail, including matrixectomy. Because toenails serve no useful function, their absence causes no functional impairment. However, surgical correction should be reserved for patients whose nails are painful or for whom the appearance of the feet is a significant factor. The most common type of surgical correction of toenails performed by dermatologists, podiatrists, or surgeons is nail excision, followed by chemical destruction of matrix tissue and nail bed with 88% phenol. After a sterile dressing is applied to the toe, the
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patient can continue normal activities. The patient needs only to change bandages and soak the feet daily until healing is complete in 2 to 3 weeks. Skin formerly below the nail plate thickens. Anyone can disguise the fact that their nails have been removed by applying nail polish to this thickened skin.
Ingrown Toenails
Causes and Findings
Ingrown toenail, a painful condition in which the medial or lateral border of a toenail penetrates the flesh, is a common problem (Fig. 73.7). Ingrown toenails have been attributed to factors such as improper trimming, heredity, bony pathology, improper shoe fit, tight socks, obesity, and trauma. However, there is no clear-cut cause, and there are probably many contributing causes. The great toe is the one almost always involved, and the problem can be identified by inspection and by finding point tenderness upon pressing the margin of the toenail.
Treatment
There is a popular misconception that cutting a V in the center of a toenail causes the lateral borders to grow toward the center, thereby relieving the ingrown condition. This belief has no basis in fact because the nail plate is merely hornified keratin: nonliving fixed tissue in which growth no longer occurs.
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FIGURE 73.7. Schematic illustration of an ingrown toenail and possible complications. |
Initial treatment of ingrown toenail depends on whether the patient's toe is infected (paronychia) or is chronically painful but not infected when the patient seeks care. The patient with an ingrown toenail often seeks help after attempting to excise the offending edge of toenail with whatever instruments are available. Most of the nail edge may be removed in this way by the patient, but a small sharp piece of nail usually remains that pierces the skin with each step and promotes infection. The toe becomes red, swollen, and exquisitely tender. The most vigorous soaking and the use of local and systemic antibiotics will not arrest such an infection as long as a nail spicule continues to penetrate the flesh. Therefore, the patient should be referred to a dermatologist, podiatrist, or surgeon for excision of the offending border of the nail; this procedure is done under local anesthesia and is curative. However, approximately 10% of patients have a recurrence, usually within 1 year. Systemic antimicrobials are rarely necessary. Definitive treatment of the ingrown nail itself varies according to the condition and needs of the patient.
For otherwise healthy patients, the procedure described for removal of the entire toenail and for matrix destruction also can be used to eradicate permanently an ingrown border. After local anesthesia (obtained by injecting the base of the toe to create a full block, injecting a field on the medial surface from dorsal to lateral and on the lateral surface from dorsal to lateral), the offending edge of toenail is excised and then phenol and alcohol are applied to cauterize the matrix tissue. This procedure, followed by complete healing in 2 to 3 weeks, usually permanently eliminates this painful and sometimes dangerous condition. Use of phenol dramatically decreases the rate of recurrence of the ingrown nail and increases patient satisfaction but at the cost of an increased postoperative infection rate (7). Even with phenol ablation of the nail matrix, there is still a 20% to 30% chance of recurrence. It is not unusual to rephenolize a nail within 1 year of treatment.
Treatment of diabetic patients and patients with arterial insufficiency must be conservative because wound healing may be poor after surgical removal of the nail. In these patients, frequent and thorough débridement of ingrown borders is effective and safe. Treatment by a podiatrist or other practitioner who is skilled in this procedure may be needed every 3 to 4 weeks to prevent complicating soft-tissue infection.
Heel Pain
Diagnosis
Heel pain is a common complaint. The most common pattern is pain that is localized to the medial plantar aspect of
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the heel. (Chapter 72 discusses heel pain localized to the posterior aspect of the heel, and Chapter 92 discusses heel pain as a manifestation of the tarsal tunnel syndrome.) Characteristically, the first step in the morning is particularly painful. The pain eases after 5 to 10 minutes of walking, but during the course of the day's activities the pain becomes progressively worse. The reason why these symptoms appear, disappear, and reappear is not understood.
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FIGURE 73.8. Radiologic view of a calcaneal exostosis (spur). (Courtesy of Max Weisfeld, DPM.) |
Examination of the foot reveals a tender area of the heel approximately 4.5 cm from the posterior margin of the plantar surface, corresponding to the medial condyle of the calcaneus. X-ray films often reveal a calcaneal exostosis or spur at the point of tenderness (Fig. 73.8). These spurs are commonly found on x-ray films of asymptomatic heels, and they are not the cause of pain in symptomatic heels. Because the attachment of the plantar fascia coincides with the point of greatest tenderness, the pain is believed to be caused by plantar fasciitis. One can picture the plantar fascia as an extension of the Achilles tendon, with the calcaneus acting as a fulcrum between fascia and tendon (Fig. 73.1B). Any condition that increases stress on the Achilles tendon may also stress the plantar fascia, such as overuse in running or jogging (especially with shoes having inflexible midsoles), excessive pronation (see above), or a sudden change to flat shoes after wearing high heels for prolonged periods. Heel pain may be a manifestation of gout or reactive arthritis, and these diagnoses should always be considered when evaluating such a patient (see Chapters 76 and 78).
Treatment
Treatment should be aimed at both the local inflammatory process and the underlying mechanical problem. Initial treatment includes using an oral anti-inflammatory medication (see Chapter 77), resting, and soaking in warm water. An injection (using a 25-gauge 1-inch needle) of a corticosteroid and lidocaine (approximately 0.5–1 mL of a corticosteroid suspension diluted with 1–2 mL of 1%–2% lidocaine) into the tender area from the medial aspect of the heel usually brings short-term relief from pain that has not responded to other measures (8,9) (see Chapters 69 and 74). Use of high-dose repository steroids should be avoided because of the risk for plantar fascial rupture after injection (9). The potential for fascial rupture may be minimized with the use of a combination solution such as Celestone/Soluspan, which combines a phosphate and acetate in one injection. Topical steroids delivered by iontophoresis may be effective (8). In some cases, stretching of the Achilles tendon brings relief. Spontaneous resolution of symptoms, over the course of months, is common (9).
Recurrent symptoms may be prevented by having the patient obtain a silicone heel pad. These pads are available in sport stores. When this pad is inserted into the shoes, it decreases tension on the Achilles tendon, so tension on the plantar fascia is reduced. The increased angulation of the foot shifts weight away from the heel to the forefoot. When a simple heel pad is not sufficient, consultation with an orthopedist or podiatrist is indicated. The consultant fabricates an appropriate orthotic to minimize pronation, raise the heel, and protect the painful area. Rarely, a painful heel requires surgical fasciotomy and removal of the spur.
Extracorporeal shock wave therapy (administered by a podiatrist) is used in very symptomatic and resistant cases (9). Extracorporeal shock wave therapy uses the same mechanism as lithotripsy but for treatment of plantar fascial pain. Although some studies show symptomatic improvement following extracorporeal shock wave therapy, other studies continue to refute the benefit of this technology. Extracorporeal shock wave therapy can be quite expensive and to date is largely not a covered benefit for many insurance plans, including Medicare (10).
Evidence is conflicting regarding the effectiveness of dorsiflexion night splints, which stretch the Achilles tendon, in patients with chronic pain (>6 months) (8).
Metatarsalgia
Definition and Pathogenesis
Metatarsalgia is pain in the forefoot. The most common condition causing metatarsalgia is Morton neuroma. In this condition, two interdigital plantar nerves between adjacent toes become compressed, inflamed, and ultimately painful. Compression of these nerves is enhanced by elevating the heel and compressing the forefoot. Therefore, women's fashionable, high-heeled, pointed-toe shoes are
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associated with this condition. In fact, 80% to 90% of patients with neuroma are female.
Symptoms and Signs
The symptoms of neuroma are specific and consistent. Typically, the patient describes a shooting, burning, or cramping pain in the foot involving two adjacent toes. The third and fourth toes are involved most commonly. However, the second and third toes often are affected as well. The patient describes spontaneous pain during walking or running. Invariably, the patient instinctively removes the shoe and massages the affected area, thereby relieving the pain. Presumably, the swollen nerve (neuroma) has been pinched by the metatarsal bones, causing the pain that radiates to the toes. Stopping walking eliminates the trauma, and massage may change the position of the neuroma. All of these measures result in alleviation of the pain.
Examination of the foot reveals that the neurovascular status is normal unless another disease is present. Palpation between the metatarsal heads reveals marked tenderness. If the forefoot is compressed while the web space is palpated, the area may be exquisitely tender.
Stress fracture of a metatarsal bone should be suspected in the case of sudden severe pain localized to a metatarsal shaft. X-ray films may be diagnostic but often are negative during the first few weeks of symptoms. Often the fracture will be apparent on repeat x-ray films in 2 to 3 weeks. Bone scans and magnetic resonance images are more sensitive diagnostic tools and often are positive before the radiograph (see Chapter 68).
Treatment
The most effective treatment of metatarsalgia is the wearing of low, flat, wide, soft, leather shoes. Corticosteroid with lidocaine injections into the web space and reaching the plantar surface (0.5 mL depo steroid with 1 mL lidocaine using a 25-gauge 1-inch needle) may provide temporary relief. Nonsteroidal anti-inflammatory drugs are ineffective. Orthotics are helpful; however, if the patient is willing to wear wide enough shoes to accommodate them, the condition usually resolves, even without the orthotic. Surgical excision is successful in 80% to 90% of cases and is indicated if symptoms persist. For patients undergoing surgery, a recovery period of 4 to 6 weeks is necessary before they can return to full activity and wear their usual shoes. Surgical complications are rare. As with most surgery, the possibility of postoperative infection is <3%. Peculiar to neuroma surgery is the possibility of recurrence. Rarely symptoms are not reduced. Because neuroma is entirely a clinical finding, exploration for a neuroma occasionally is fruitless. Fortunately, neuroma is also an uncommon occurrence, but the possibility should always be told to the patient before surgery.
Metatarsalgia not caused by neuroma is more difficult to characterize, evaluate, and treat. Nonneuritic metatarsal pain may occur anywhere in the forefoot with or without radiation and may be exacerbated by high-heeled or, at times, low-heeled shoes. Palpation often reveals pain directly on a metatarsal head rather than between them. Rest, application of ice, and elevation of the foot may help some patients, but most require referral to a podiatrist for padding, orthotics, or other treatment. Metatarsal stress fractures are another cause of metatarsalgia, usually characterized by sudden onset and pain on palpation over the involved metatarsal bone. Often there is no history of trauma. The use of shock-absorbing insoles in footwear has been shown to reduce the incidence of stress fractures in athletes and military personnel (11).Chapter 68 discusses the diagnosis and management of stress fractures.
Specific References*
For annotated General References and resources related to this chapter, visit http://www.hopkinsbayview.org/PAMreferences.