Identifying Foot and Ankle Pathologies
Many lower-extremity conditions can lead to physical decompensation, depression, falls, infection, and complications as severe as amputation.
Older adults are at increased risk for a variety of foot and ankle pathologies. Common lower extremity pathologies seen in the aging population include skin and nail changes; decreases in circulation and sensation; wounds due to varied causes; mechanical deformities such as bunions and hammertoes; and degenerative joint disease due to hereditary and biomechanical factors. These conditions can have a significant impact on older adults' quality of life and increase their risk of local and systemic complications.
Treatment of many lower extremity conditions requires immobilization, and this decreased activity can affect patients' physical and mental well being and can lead to physical decompensation, depression, falls, infection, and even more severe complications such as amputations. For this reason, the prevention of foot and ankle problems is a priority in the aging population.
Prevention of lower extremity-related conditions in the elderly must begin with a thorough understanding of foot and ankle problems for which the elderly are at risk, and how their response to these conditions may differ from the younger population. A thorough history and lower extremity physical exam should be performed, specifically looking for circulatory, neurologic, mechanical, and infectious conditions. These conditions are the most common in causing debilitation and leading to long-term complications in the elderly.
Rapid identification of these conditions promotes early intervention and may help to avoid extensive convalescence. Prevention also requires detailed education not only for patients, but also for families and/or caregivers. Patients identified as being at high risk for developing serious lower extremity complications should have interval reevaluation as part of an organized care management program. As noted above, a thorough extremity exam should focus on the circulatory, neurologic, dermatologic, and musculoskeletal systems. We recommend the following evaluation for all elderly patients.
• Manual palpation of pedal pulses: The examiner should be able to easily palpate both the dorsalis pedis and posterior tibial pulses. If questions regarding the presence or quality of the pulses are noted, a hand-held Doppler can be used to listen to the waveforms and ensure patency of flow.
• Capillary fill time: Capillary blanching with manual pressure should return to normal color within three seconds. Sluggish capillary refill can be a sign of either occlusive vascular disease or vasospastic disorder.
• Skin quality: The color, temperature, and turgor of the pedal skin should be consistent with the proximal leg and the upper extremities. A significant decrease in the temperature gradients from proximal to distal can signal vascular impairment. Additionally, significant loss of skin turgor, dryness, and loss of hair growth can be signs of atrophy from lack of circulation.
• Lower extremity venous changes: Pretibial or malleolar edema, varicosities, and stasis changes such as hemosiderin deposition, induration, scaling skin, and atrophy are signs of underlying venous disease.
If there are concerns regarding a patient's vascular status, then further testing to identify peripheral vascular disease, such as Doppler arterial waveform and segmental pressure exam, should be performed. These tests can provide a better understanding of the arterial status of a lower limb. Decreased circulation can result in calf pain with ambulation (claudication), or when the blockage and ischemia are more advanced, the patient may experience rest pain or spontaneous ulceration. Increased risk of infection and wound healing problems are associated with ischemia. Patients with diminished circulatory status should be referred to a vascular specialist for evaluation as well as a foot and ankle specialist for regular high-risk assessment.
Neuropathy can also result in gait disturbances and increased fall risk in elderly patients. Interventions should include education on proper footwear and bracing, and physical therapy should be considered. Patients with neuropathy and associated risk factors such as deformity and/or poor circulation need to have regular high-risk foot assessments.
Neurologic assessments should include evaluation of the following:
• Protective sensation to the plantar foot assessed with Semmes-Weinstein Monofilament: This test is performed with a 10g monofilament to test superficial sensation at multiple locations on the dorsal and plantar foot and has been correlated with the risk of ulceration. Decreased protective sensation as seen with aging (idiopathic), as well as in combination with diabetes mellitus, puts patients at severe risk of ulceration.
• Vibratory sensation: One of the earliest clinical signs of sensory loss in the foot is vibratory sense. A 128-hz tuning fork is used to test the patients perception of the vibration and time of decay compared with the examiner's perception.
• Deep tendon reflexes: It is not uncommon for elderly patients to have a decrease in ankle reflexes. This is often explained by the loss of elasticity of the Achilles tendon, rather than an actual change in the nerve or reflex arc. Ankle reflexes can also be diminished in the presence of joint disease that limits motion of the ankle joint.
If deformities are present in the absence of other subjective or objective concerns, then education on shoe gear and monitoring is usually appropriate. If pain is present, this can often be addressed by advising elderly patients about appropriate footwear with adequate support and room for the deformity, along with an orthotic to aid in foot function and decrease strain on structures. Specific recommendations and guidance on appropriate footwear and the most appropriate orthotic for each patient should be made. If the deformity or pain is severe, such as in end-stage degenerative joint disease, then bracing with an ankle-foot orthotic may be the most appropriate option. Physical therapy for range of motion, strengthening, and gait improvement with a focus on balance may also be appropriate.
Examination for musculoskeletal conditions should assess for the following:
• Presence of deformities such as bunion, tailor's bunion, hammertoes, prominence of the metatarsal heads plantarly, and other bony prominences should be noted as these are common sources of irritation and/or ulceration. At the same time the patient's shoe gear should be assessed for proper style and fit. Deformity, neuropathy, and poorly fitting shoes are the most common causes of foot ulcerations.
• Pain on palpation or with range of motion of the ankle, midfoot, or forefoot joints can indicate an arthritic condition. Swelling and/or joint effusion may differentiate an inflammatory or acute condition from chronic degeneration.
• Foot type with weight bearing, eg, high or low arch and heel position with standing can contribute to pathology. Understanding a patient's foot type and mechanics can help to identify reasons for pain, such as plantar heel and arch pain, tendon pain, and joint pain. With knowledge of the weight-bearing position and function of the foot, diagnosis can more easily be made and treatment instituted.
• Gait evaluation can be a valuable tool to assess a patient's risk of falls. In some cases, gait instability is related to lower extremity sensory or proprioceptive neuropathy. In some cases, shoes that are poorly fitted, worn out, or unstable contribute to the instability.
Surgical intervention is considered in situations in which a deformity is painful; conservative treatment has failed; a deformity is resulting in other ongoing problems such as recurrence of callouses or ulcerations; and the patient is an adequate surgical candidate. For surgical intervention, the risk-to-benefit ratio must be weighted for each individual patient.
During an overall skin survey, clinicians should note the skin texture and turgor, as well as the presence of fat pad atrophy. Areas of erythema from pressure or rubbing, interdigital lesions or maceration, open wounds, ulceration, rashes, and other dermatologic abnormalities must be identified. The integumentary exam can give additional insight into the circulatory status of the limb.
Clinicians should also examine the patient for hyperkeratotic lesions (callouses). When mechanical deformities are present and there are increased areas of pressure, friction, or rubbing, the likelihood of callous formation increases. Callouses must be carefully debrided in high-risk patients to prevent further breakdown, and then the source or sources of the callous must be addressed. Often an elderly patient may be wearing a shoe that's too short or too narrow (tight). Appropriate shoe gear must be addressed with both the patient and family.
Lastly, check for focal edema or bruising, which may be a sign of trauma or underlying injury.
There are multiple treatments available for nail changes due to fungal causes, including topical and oral medications and laser treatments. The efficacy of those treatments is questionable and for success to occur, the care provider must ensure that the changes are indeed due to fungal infection. The risk/benefit ratio must be determined prior to instituting these forms of treatment.
For most elderly patients, the mainstay of treatment for dystrophic or gryphotic nails is periodic debridement to decrease thickness. When nails are thick, there is an increase in pressure on the underlying nail bed, particularly if patients wear ill-fitting shoes. This increased pressure can lead to nail bed ulceration, and if present in combination with neuropathy and/or peripheral vascular disease, can ultimately lead to digital amputation.
If a patient has nail changes and associated risk factors such as neuropathy and/or peripheral vascular disease, it's important to schedule for regular follow-ups with a foot and ankle specialist to debride and decrease the risk of ulceration. If the nail changes are seen without associated risk, then provide proper education on appropriate debridement to both the patient and family.
Wound Types and Treatment
The key to treatment and healing of a venous stasis ulcer is control of the edema. There is a role in medication treatment of the fluid retention, but the mainstay is compression of the lower extremity to decrease the edema. Multilayer graduated compression should be used in conjunction with moist wound care to the ulcer. Debridement of venous ulcerations is rarely needed. The patient should also be educated on elevation of the lower extremity to aid in edema control. Once the ulcer is healed, a compression stocking with appropriate pressure should be used to maintain edema control and prevent recurrence. In some instances, referral to a vascular specialist to assess the degree of venous reflux and consideration of venous ablation may be necessary.
Treatment involves a thorough vascular examination as noted previously and comanagement with a vascular specialist to determine whether vascular inflow can be improved. Topical wound care varies significantly between moist to dry, and depends on the depth, stage, and level of ischemic changes present. Appropriate debridement also varies based on the circulatory status of the patient and the characteristics of the ulceration.
Mixed Etiology Ulcerations
Assessing Risk Level
— Mindi Feilmeier, DPM, FACFAS, is a podiatrist and an assistant professor in the College of Podiatric Medicine and Surgery at Des Moines University in Iowa.
— Paul Dayton, DPM, MS, FACFAS, is a podiatrist at UnityPoint Clinic Foot and Ankle and Trinity Regional Medical Center in Fort Dodge and an assistant professor in the College of Podiatric Medicine and Surgery at Des Moines University.