The Aged Foot

Original Editors - Scott Buxton

Top Contributors - Scott Buxton

Introduction

Foot problems are commonplace in people over the age of 75 moreso than a younger population[1]. Foot impairment contributes to falls, immobility, the progression of frailty and can lead to a quicker progression towards dependence and not independence[2]. It is understandable that even without co-morbidity to spped up progression of the effects of aging feet are often affected. Consider how many miles an average person walks in their lifetime. 

The average moderately active person take around 7,500 step/day. If you maintain that daily average and live until 80 years of age, you'll have walked about 216,262,500 steps in your lifetime. Doing the math, the average person with the average stride living until 80 will walk a distance of around 110,000 miles[3].

The management of the aged foot is typically aimed at achieving comfort through the reduction of pain as well as increasing mobility. Both ultimately preventing dependence and reduce the need and demand for other services. Thankfully most common issues can be treated successfully by Podiatrists as well as Physiotherapists. The aim of this article is highlight the common issues as well as basic methods of management.

A Word of Caution...

Just before diving into the information below please make sure you consider the impact different management strategies will have on the older person as a whole. The person is more than a foot ulcer, more than someone with foot pain, they are often vulnerable and frail. Slight alteration to their routine or body may cause unintended concequences to their coping strategies and they may not be able to tolerate the treatment anyway. Quite often their ability to cope is in fine balance and something you or I appear to be minor can have vast concequences for them. Sometimes less is more in the context of elderly care.

Prevalence

It is estimated that around 80% of older people have foot problems however many of these people do not seek medical attention[4][5]. Multiple studies in many countries have found the same, older people do not seek help for foot problems even when something can be done about it[6].

The most common foot problems tend to be nail problems, calluses, bunions, corns, hallux valgus, generalised pain, swollen feet and circulatory problems[7]. Most of these issues derive from poorly fitting shoes, obesity and chonic conditions such as diabetes, cardiovascular disease or osteoporosis[8].

Common Problems

The problems listed below are not all physiotherapy ameanable however it is important that physiotherapists are aware of them and how they can affect an older person. In particular all of these issues can contribute to a multifactorial picture of falls.

Toenail Issues

Toenail issues arise because of many issues but the largest contributor is likely the fact that cutting is difficult.

31% of older people are unable to cut their own toenails because[9]:

  • Unable to reach their feet
  • Lack finger deterity to the point they are unable to use the clippers
  • Get dizzy when bending
  • Of visual  impairment
  • Thick toenails

It is also estimated that around a third of older people have fungal infections of the toenail, even higher in those with diabetes, CVD or obesity[8].

With advancing age growth rate and morphology of the nail plate occurs with a reduction in growth rate as well as changes in colour and contour[10]. They tend to become a yellow-gray colour and can become opaque and a peculiar discolouration called "Neapolitan nail" occurs in ~20% of older people[11]. The nail can also become fissured, split or striated which can cause some alarm for some people. It is important to note that all become more common in those with osteoporosis[11].

Brittle nails (fragilitas unguium) affects around 20% of the population and in most places in the world this is a conservative estimate in the elderly population. It clinically manifestd with varying degrees of onychoschizia (localized hypertrophy of the nail plate) or onychorrhexis (subungual corn).

Onychoschizia is usually caused by impairment of intercellular adhesion between the corneocytes that make up the nail plate. This results in transverse splitting due to breakage of the lateral edges of the nail plate and in lamellar splitting of the free edge and distal portion of the nail plate. Exogenous factors (eg, repetitive cycles of wetting and drying, trauma, and fungal proteolytic products) and chemicals or cosmetics (eg, cuticle removers, nail enamel solvents, and nail hardeners) are among the underlying causes. Onychorrhexis, on the other hand, frequently manifests as nail plate splitting or ridging, longitudinal thickening, or multiple splits leading to triangular fragments at the free edge. It is usually the result of nail matrix involvement leading to abnormalities in epithelial growth and keratinization. Among the various factors causing onychorrhexis are abnormalities of vascularization and oxygenation (such as anemia or arteriosclerosis), as well as systemic (metabolic, endocrine, etc) and dermatologic diseases (disorders of cornification and inflammatory diseases).

Onychomycosis is the most common nail infection (representing around 50% of all infections) and is common in the elderly[12]. Increased risk of onychomycosis is associated with multiple factors, including male sex, old age, smoking, underlying medical diseases (eg, peripheral arterial disease, diabetes, and immunodeficiency), and predisposing genetic factors[12].

Bunion / Hallux Valgus

Foot width and length often increases with age in addition to peripheral swelling which often occurs throughout the day[13]. This change in shape can lead to misshapen joints resulting in pressure changes in the skin leading to bunions.

A bunion is a bony deformity of the joint at the base of the big toe. The main sign is the big toe pointing towards the other toes on the same foot causing a swollen bumpy lump on the medial aspect of the foot. This causes a painful callus to form which could potentially develop into a sore[14].

Symptoms include:

  • a swollen, bony bump on the outside edge of your foot
  • pain and swelling over your big toe joint that's made worse by pressure from wearing shoes
  • hard, callused and red skin caused by your big toe and second toe overlapping
  • sore skin over the top of the bunion

Corn / Callus

As well as being caused by bunions ill-fitting shoes and the deterioration of fat pads can lead to pressure areas. This is called a corn or callus. They are circular masses of tissue which form on the outside of the toes, usually the outer ones, which is painful on direct pressure. They are usually caused by ill-fitting shoes and deterioration of fats pads.

Ankle Osteoarthritis

Ankle osteoarthritis is the occurrence of osteoarthritis (OA) in the ankle joint. The ankle joint consists of two synovial joints, namely the talocrural joint and the subtalar joint. In both joints osteoarthritis can be diagnosed in the medial and the lateral compartment[15]

The ankle joint is far less commonly affected by arthritis than other major joints. The reasons for this include differences in articular cartilage, joint motion, and the susceptibility of cartilage to inflammatory mediators. There is relatively good containment and conformity of the ankle joint, the talus is firmly bound on three sides by the fibula, tibial plafond and medial malleolus and their strong ligamentous attachments. This design potentially gives the ankle a better cartilaginous loading profile. The most common cause of end-stage arthritis of the ankle is trauma. Additional causative factors include arthropathies, chronic ankle instability, malalignment, and certain medical conditions, such as hemophilia.

In terms of which type of OA tends to occur in the ankle it tends to be primary OA.

This is the form of osteoarthritis in which you don't know what could trigger the disease. You can't infer anything from history, nor clinical or radiographic examination[16].

Compared with results reported for knee and hip, there is a substantially lower rate of primary ankle OA. Although early cartilage degeneration occurs, progression to severe grades of degeneration is not frequently observed[17] . This phenomenon is thought to be caused by the unique anatomic, biomechanical and cartilage characteristics of the ankle. Specifically the ankle has a smaller contact area than the hip or knee in a load-bearing pattern and subsequently pressure distribution is different which explains the differences between joints[18]. There is also a relative higher cartilage resistance in the ankle, which might protect it from degenerative changes leading to primary OA. This higher cartilage resistance in the ankle is due to the fact that the ankle is primarily a rolling joint with congruent surfaces at high load, which allows it to withstand large pressures[19]. Although the ankle cartilage is thinner compared with knee or hip cartilage, it shows higher compressive stiffness and proteoglycan density, lower matrix degradation and less response to catabolic stimulations. So the ankle is not generally a site of primary OA (This occurs only in approximately 7% of all ankle OA cases).

Gout

Gout is a crystal-induced arthritis, in which monosodium urate (MSU) crystals precipitate within joints and soft tissues and elicit a highly inflammatory but localized response. The susceptibility to form MSU crystals is a consequence of excessive blood levels of soluble urate, one of the final products of the metabolic breakdown of purine nucleotides. Hyperuricemia is typically defined as occurring above the saturation point of MSU, at which point the risk of crystallization increases. Using this definition, hyperuricemia occurs at serum urate levels >6.8 mg/dL [20].

Gout is often described as a burning pain and can be extremely severe in nature with an attack lasting upwards of a week. During this period of immobility an elderly person can lose a significant amount of independence and may require help to function.

While gout is commonly considered to be a disease affecting men, this gender difference diminishes after the age of 65, likely due to hormonal influences[21]. Several factors contribute to the high prevalence of gout in the elderly. The risk of gout is related to the duration of hyperuricemia, and hence related to longevity. Increase in cardiovascular, renal, and metabolic morbidity in the elderly, resulting in decreased GFR and reduced uric acid excretion, along with polypharmacy, may precipitate hyperuricemia[22][23].

In many frail elderly people gout can often be interpreted as something more severe such as a fracture or infective arthritis. This is because a flare of a disorder can knock those who have 'just about been coping' with all of their other morbidity over the edge. With their body now unable to cope with a new complaint they often become immobile and unable to function as before. 


Gout foot.jpg


Hallux Rigidus

Hallux Rigidus is a progressive disorder. The toe’s motion is decreased over time. Some causes are faulty function or biomechanics and structural abnormalities which can lead to OA.

Hallux rigidus XR.jpg
Pain, stiffness and loss of motion are the some signs of hallux rigidus. Burning pain and paraesthesia can be present. Walking, standing and wearing heels aggravate the pain. Symptoms are relieved by rest. The normal dorsiflexion range of motion of the first MTP joint is at least 65 degrees[24] showed a new standard of “normal” range of dorsiflexion range of motion of the great toe joint should now be set at approximately 45 degrees. 

Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systematic autoimmune inflammatory disease and results in persistent inflammation of synovial tissue especially of the wrists, hands and feet. Individuals with RA are 8 times more likely to have functional disability compared with adults in the general population from the same community. The structures around the joint can also be affected, like the tendon sheath, the bursa and tendons. This pathology causes pain, stiffness in the morning and after periods of inactivity, joint swelling, weakness, fatigue and restricted joint mobility leading to reduced function. Without treatment RA can lead to irreversible damage, namely deformity and finally provoke considerable physical functional loss or even permanent disability. Thus, RA causes dramatic interference with quality of life if early diagnosis and appropriate treatment are not obtained. [25][26]

In rheumatoid arthritis joint complaints are on the foreground. Typically in a first stage  there is a chronic, symmetrical inflammation of the joints of the hands and the feet, especially the metatarsophalangeal joints (MTP), the wrists, the metacarpophalangeal joints (MCP) and the proximal interphalangeal joints (PIP). Softening of the ligaments can lead to deformation of the fingers, like luxations of the metacarpophalangeal joints. Rheumatoid arthritis causes deformity, pain, weakness and restricted mobility and will result in loss of function.[27]

Diabetic Foot Ulcers

15-20% of diabetics will develop a foot ulcer in their lifetime and effective monitoring is essential to prevent further issues developing alongside[28]. The NICE in England recommends an annual check for all with diabetes with all assessments including:

  • Loss of sensation and callus formation
  • Reduction blood supply from diseases such as PVD, renal failure, poor diabetes control and CVD 
  • Bony deformities or changes
  • Impaired ability to care for yourself through cognitive or physical impairment

One of the largest reason for ulcers occurring is that diabetic neuropathies (appearing in almost 50% of older people with T2DM[29]) prevent the person from feeling areas of increased pressure. Things are worse in those which suffer from distal sensory polyneuropathy as symptoms are so variable, with some neuropathies being pain free. In this case the end of the toes can become completely numb and therefore a sore is easily created, leading to an ulcer in no time. 

Up to 50% of patients with neuropathy never experience symptoms, so absence of neuropathic symptomatology must never be associated with absence of risk of foot ulceration.

This is where hot/cold, pin prick sensation and vibration testing all come into their own. This is how you assess the loaction and severity of neuropathy and act upon it swiftly, if not the person is at 6x the risk of develping an ulcer[30].

Peripheral autonomic dysfunction also contributes to ulcers through increased peripheral blood flow in the absence of large vessel obstructive vascular disease, together with dry skin because of a lack of sweating. This along with neuropathy creates a warm dry and insensitive foot.

The above mechanism usually leads to an ulcer developing overtime however the insensitive foot is also at high risk of trauma, particularly in those elderly who are still doing their own higher acitvites of daily living such as gardening. 

Taken from Boulton, A. Pressure and the diabetic fot: clinical science and offloading techniques. The A J Surg. 2004:187;17s-24s.

Biomechanics also plays a part in the development of ulcers, particularly in those with high plantar pressures[31]. This high pressure leads to a mechanical recurrent stress which the patient is unable to feel. Eventually the skin becaomes sore, breaks down and becomes ulcerated. This is particularly an issue for those mobile elderly who have an altered gait pattern due to something such as osteoarthritis, and this is where awareness of their frailty comes into play. It is particularly important to consider such issues as the damage caused by repetitive application of high pressures over a bony prominence beging deep and is not visible. 

Skin

As you age skin becomes thinner, loses fat, takes longer to heal and is more prone to damage. 

Obesity

15% of men and 28% of women over 60 are obese and this has a significant effect on the biomechanics of the feet. Obese elderly tend to have a higher incidence of foot pain because of structural changes and this also has implications for day to day life, mobility and general well-being. They tend to have larger foot dimensions, thicher plantar fat pads under the heels, a lower hallux and overall foot strength. These contribute to generating a higher overall force, a greater plantar contact time with a greater contact area therefore greater pressure-time. Therefore providing interventions to combat their obesity ensures a reduction in foot pain, an increase in independence and better overall quality of life[32].

Management

It is important that with older people you remember to think about the person as a whole and in terms of their frailty and falls risk.

Prevention

  1. Regular Checks. Long-term conditions increase the likelihood of developing issues particularly those disorders which affect circulation. The signs of deterioration are subtle and therefore long-term vascular issues need to be monitored. It is essential that alongside regular check-ups those most vulnerable seek primary care advice as soon as any new issues arise such as blisters, cracks or obvious changes. Prevention is the best protection, you do this with your eyes, why is it different for your feet?
  2. Nails. As we age it is increasingly difficult to reach our toe nails but cutting them should not go to the wayside. Poorly looked after nails can become ingrown and infected resulting in pain and immobility. The nails get long, press against shoes, the pressure causes sores, the sores become infected and then ulcerated. You look after your fingernails, why not your toenails?  
  3. Skin Quality. As we age our skin becomes dry, cracked, have a reduced circulation and a reduction in fat pad absorption. Once the dryness and cracked skin with sores sets in they are a rife place for infection. Cellulitis is common in elderly people and frequently reoccurs. You care about the skin on your face, why not your feet?
  4. Correct Footwear. Optimum alignment and weight distribution is essential to keep joints and soft tissues working effectively. A good pair of closed heel flat shoes with good shock absorption promotes good walking posture and balance whislt reducing any risk of chaffing or rubbing. Additionally they should be roomy enough to allow for minor swelling which occurs during the day. Why do you think runners spend so much on good quality running shoes?

Essential Care

Some basic essential care points can make all the different for elderly people[9].

  • Ideally daily washing
  • A good and thorough drying routine
  • Avoiding talcum powder
  • Fresh socks
  • Moisturising the feet avoiding over apllication between the toes
  • Routinely buying new footwear and minimal use of slipper

Ulcers 

When considering the prevention or management of ulcers in older people it is essential that you consider the implications of their other issues.

As with all aspects of managing the foot prevention is the patients best friend. During assessment it is essential that the therapist is aware of areas of high pressure as to then offload it through different approaches[29]. One of the oldest techniques (and most effective) is offloading footwear and those wearing appropriate footwear have significantly fewer ulcers[33]. Don't forget that if the ulcer is severe enough then bed rest, the use of wheel chair or crutches can also be appropriate. A word of caution though, bed rest can lead to rapid deconditioning and immobility in elderly so perhaps casting or therapeutic shoes is more appropriate.

Gout

Aside from the management of hyperuricemia and the pharmocology-side of the treatment physiotherapy is important. Patient education, optimising mobility and lifestyle modification are essential parts of the holistic gout management plan.

It is important that the elderly person with gout remains as active as possible during the attack of symptoms as the rest of their muscular system will atrophy and it may be difficult to get the muscle bulk and function back afterwards. Seated or weightbearing exercise plans are a suitable options alongside provision of mobility aids. For those elderly able to attend outpatient clinics ultrasound therapy may also be an option. As gout is an inflammatory disorder don't forget the efficacy of ice.

It is also that the person avoids alcohol, highly calorific food, sea food in the long term and if applicable to them, optimisie their BMI. This will reduce the risk of ongoing flares[34].

Toenails

Owning individual nail clippers and files prevents corss contamination of infections along with regular washing and maintenance[13]. Toenail cutting services may be an alternative option to those unable to cut their own nails.

Top tips include:

  1. Easier to cut after having a warm bath
  2. Straight cuts to the nails
  3. Filed sharp or rough edges

In the context of brittle nails it is important to consider the predominance of either onychoschizia or onychorrhexis and then correct these underlying issues. General therapeutic management may include nail hydration with daily 15-minute soaks using emollients rich in phospholipids[35]. pplication of nail hardeners containing formaldehyde can be used to strengthen the nail plate[35]; nevertheless, caution should be entertained when using these products, as they might cause brittleness, subungual hyperkeratosis, or onycholysis (ie, separation of the nail plate from the underlying nail bed). Mechanical nail plate protection and fracture filling can be accomplished using enamel; however, considerable dehydration might occur when it is removed afterward.

Overall it is not always the physiotherapists job to manage the nail conditions however, basic advice is always worth sharing with the patient. The main thing to be aware of is that elderly patients might complain of common nail changes and dystrophies that cause pain, affect daily activities, are of cosmetic concern. Awareness of these conditions is essential for onward referral to optimally manage the issues.

Skin

Keeping feet moisturised is an essential part of caring for aged skin which is prone to drying out.

Bunions

A bunion may only need treatment if it is severe and causing significant pain and alteration to daily life. Non-surgical options incluse pain killers, bunion pads and orthotics all alongside appropriate footwear. It is important to be aware that surgery is the only way to correct a bunion and is not for cosmetic reasons alone[36]. The surgical options include an osteotomy, which is removal of the problematic part of the bone alongside correction of any soft tissue deformity which has occurred. Arthrodesis is also an option. This is when the metatarsophalangeal joint is fused and is only recommended in severe joint degeneration. 

[37]
[38]

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