Focus on the Foot: Changes With Age and Disease

As one ages, the ability to retain ambulation is directly related to foot health. The feet are important for weight bearing, balance, and mobility.¹ Sustained mobility often enables older adults (i.e., persons aged 65 years and over) to maximize their independence and ability to socialize. Impaired ambulation secondary to localized foot conditions and focal complications of systemic diseases can transform active seniors into individuals who become dependent on family and other caregivers. A keen mind and the ability to retain mobility are two important factors involved in a senior patient’s ability to remain a vital part of society.²

The comfort and care of feet are often neglected. Foot problems associated with aging or disease processes (TABLE 1 ) often go unrecognized and untreated. This article will address selected foot problems; a comprehensive listing of foot manifestations of systemic diseases may be found in Reference 3.

Age-related and disease-related foot problems can create situations in which older adults experience pain, decreased range of motion, and infection, thereby decreasing their functional ability to ambulate well. Common causes of pain and disability in the elderly are nail and skin problems (predominantly corns and calluses), along with circulatory and structural problems ( TABLE 1 ).⁴ Contributing factors, such as repetitive stress and structural changes in the foot, have the potential to further compromise function.⁵ Additionally, foot pain, as with other painful conditions and disorders, has the potential to impair sleep. Of note, gait and posture impairment (e.g. swaying) may be indicative of arthritis of the hip or knee, Parkinson’s disease, stroke, or cerebellar, subcortical, or basal ganglia dysfunction.⁶

The incidence, prevalence, and severity of foot conditions increase with age.^2,7 More than 75% of older adults complain of foot pain secondary to a significant foot problem and have radiographic evidence of arthritic changes.^1,8 It has been estimated, on average, that 90% of the adult population over the age of 65 years will exhibit some evidence of foot pain capable of altering independent activity.² When an individual loses the ability to walk as a result of a foot problem, physical limitations are not the only manifestation; there is also a significant impact on the patient’s mental, social, and economic status.²

The complex structure and function of the human foot involves bones (26 in each foot), ossicles, ligaments, muscles, tendons, arteries, veins, nerves, and skin.² Feet that ache, appear distorted, or exhibit discoloration need attention. In order to assist older adults in maintaining their independence and optimizing their choices for quality of life, foot problems need to be properly diagnosed and treated.^1,6 Since seniors with orthopedic conditions may have comorbid foot problems, it is important for clinicians to distinguish between minor foot problems that can easily be treated and more serious conditions that require referral to a specialist.⁴ In seniors with foot problems, regular evaluation and treatment should take place under the care of a podiatrist.⁶ Educating patients and their caregivers about simple preventive techniques is crucial (see Resource).^7,9

Plantar Fasciosis

Plantar fasciosis is the most common cause of foot pain presented in outpatient medicine.^10,11 This condition causes pain at the site where the plantar fascia attaches to the calcaneus (heel bone).³ Pain at the bottom of the heel on weight bearing (usually upon arising in the morning) usually improves within 5 to 10 minutes and returns later in the day; burning or sticking discomfort or pain along the plantar medial border of the foot when walking may occur in some patients.³

While complaints of pain in the plantar fascia have been called plantar fasciitis, plantar fasciosis is a more accurate term, since there is usually no inflammation involved.³ There may, however, be acute or chronic stretching, tearing, and degeneration of the fascia at its attachment site. This condition may also be known as calcaneal spur syndrome or heel spur, even though there may be no bone spurs on the calcaneus.³

Causes of plantar fasciosis include shortening or contracture of the calf muscles and plantar fascia. Risk factors include sitting for long periods, very high or low arches in the feet, and wearing high-heeled shoes; it is commonly seen in runners and dancers and may occur in individuals whose occupations require standing or walking on hard surfaces for prolonged periods of time.³ Obesity, rheumatoid arthritis, reactive arthritis, and psoriatic arthritis may be associated with this condition. In addition, repeated corticosteroid injections may cause degenerative changes of the fascia and potential loss of the subcalcaneal fat pad, contributing to this condition.³

Diagnosis is chiefly clinical. An MRI is done if an acute fascial tear is suspected.³ Treatment involves calf muscle and plantar soft-tissue foot-stretching exercises, night splints, and foot orthotics (prefabricated or custom-made).³ The patient is advised to take shorter steps and avoid walking barefoot. In addition, activity modifications, NSAIDs, weight loss if appropriate, cold and ice massage therapy, and occasional corticosteroid injections may be utilized.³ However, as mentioned above, since corticosteroid injections can predispose to plantar fasciosis, many clinicians limit these injections. For resistant cases, prior to consideration of surgical intervention, physical medicine, oral corticosteroids, and immobilization with a cast should be used.³

Onychomycosis

Onychomycosis is a fungal infection of the nail plate and/or nail bed causing deformed and white or yellow discolored nails.¹² About 10% of the population has onychomycosis with toenails being 10 times more commonly infected than fingernails.¹² Deformity causes the nails to thicken and accumulate keratin and debris underneath the nail and distally from it, so that the nail separates from the nail bed. A form called proximal subungual onychomycosis is a marker of immunosuppression; the white superficial form may also occur, causing a chalky white scale to spread beneath the nail.

Risk factors include advanced age; male sex; tinea pedis (athlete’s foot) or exposure to someone with tinea pedis or onychomycosis; nail dystrophy; peripheral vascular disease or diabetes; and immunocompromise.¹² Of note, onychomycosis may predispose patients to lower-extremity cellulitis.¹²

Diagnosis is made visually, by wet mount, culture, polymerase chain reaction (PCR), or by a combination of these methods.¹² Since many cases of onychomycosis are asymptomatic or mild and not likely to cause complications, this condition is not always treated, in light of the risk of hepatotoxicity and serious drug interactions associated with effective systemic drug therapy. When treatment is indicated (e.g., diabetes or other risk factors for cellulitis, previous ipsilateral cellulitis), oral terbinafine or itraconazole is selectively used.¹² Since these agents remain bound to the nail plate and continue to be effective after oral administration has ceased, it is not necessary to treat until all abnormal nail is gone; while the infected nail remains with deformity, the new nail will appear normal.¹² Antifungal nail lacquer containing ciclopirox 8% applied topically is best used as an adjunct to improve the cure rate with oral drugs, especially in resistant infections. Other measures include thoroughly drying feet after bathing, wearing absorbent socks, using antifungal foot powder, trimming nails short, and discarding old shoes that may harbor an abundance of fungal spores.¹²

Ingrown Toenail

A pain-causing incurvation or impingement of a nail border on its adjacent nail fold is known as an ingrown toenail or onychocryptosis.¹² This condition can be caused by ill-fitting tight shoes, an abnormal gait such as toe-walking, bulbous toe shape, excessive trimming of the nail plate, or congenital nail contour variations; peripheral edema is a risk factor in older adults.¹² Infection can eventually occur along the nail margin (paronychia), causing redness, swelling, and pain.¹² In the elderly, the evidence of tissue granulation around the toe should prompt investigation of possible amelanotic melanoma, which requires biopsy.¹²

In most cases, and particularly with paronychia, excision of the ingrown toenail (after injecting a local anesthetic) is the only effective treatment.¹² Shoes with a larger toe box are indicated if patients are wearing shoes that are too tight. Recurrence of ingrown toenails requires permanent destruction of the nearby lateral nail matrix via phenol or trichloroacetic acid application or via surgical excision; phenol should not be utilized in patients with arterial insufficiency.¹²

Conclusion

In the aging patient, changes that compromise mobility may occur in the foot and associated structures as a result of the aging process or systemic disease, constituting a significant health concern. Furthermore, foot problems may be a barrier to independent living or participation in activities in assisted living communities. Regular evaluation and effective treatment should take place, while educating patients and their caregivers about simple preventive techniques.

REFERENCES

1. Mitty E. Nursing care of the aging foot. Geriatr Nurs. 2009;30:350-354.
2. Helfand AE. Primary considerations in managing the older patient with foot problems. In: Halter JB, Ouslander JG, Tinetti ME, et al, eds. Hazzard’s Geriatric Medicine and Gerontology. 6th ed. New York, NY: McGraw-Hill; 2009:1479-1490.
3. Foot and ankle disorders. Musculoskeletal and connective tissue disorders. Updated March 2008. www.merckmanuals.com/professional/musculoskeletal_and_connective_tissue_disorders.html. Accessed September 17, 2012.
4. Bryant JL, Beinlich NR. Foot care: focus on the elderly. Orthop Nurs. 1999;18:53-60.
5. Anderson J, White KG, Kelechi TJ. Managing common foot problems in older adults. J Gerontol Nurs. 2010;36:9-14. doi: 10.3928/00989134-20100831-03. Epub 2010 Sep 22.
6. Porter RS, Kaplan JL eds. The Merck Manual of Diagnosis and Therapy. 19th ed. Whitehouse Station, NJ: Merck Sharp & Dohme Corp. 2011:3084-3085, 3088.
7. Robbins JM. Recognizing, treating, and preventing common foot problems. Cleve Clin J Med. 2000;67:45-47, 51-52, 55-56.
8. Ebersole P, Hess P, Luggen AS. Toward healthy aging: Human needs and nursing response. 6th ed. Amsterdam: Mosby/Elsevier; 2004.
9. Osterman HM, Stuck RM. The aging foot. Orthop Nurs. 1990;9:43-47, 76.
10. Hellmann DB, Imboden Jr. JB. Musculoskeletal and immunologic disorders. In: McPhee SJ, Papadakis MA, Rabow MW, eds. 2011 Current Medical Diagnosis & Treatment. 50th ed. McGraw Hill Medical; New York, NY. 2011: 779-840.
11. Neufeld SK, Cerrato R, et al. Plantar fasciitis: evaluation and treatment. J Am Acad Orthop Surg. 2008;16:338-346.
12. Nail disorders. Dermatologic disorders. Merckmanuals.com. Updated October 2009. www.merckmanuals.com/professional/dermatologic_disorders.html. Accessed September 17, 2012.
13. Helfand AE. Foot problems. Peripheral arterial, sensory and diabetic problems. In:   Capezuti EA, Siegler EL, Mezey MD, eds. The Encyclopedia of Elder Care. 2nd ed. New York, NY: Springer Publishing Company; 2008:316.
14. Dorland’s Pocket Medical Dictionary. 28th ed. Philadelphia, PA: Elsevier Saunders: 2009.

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