Assessment of Foot Neuropathies

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Neuropathy Assessment

For a review of foot neuropathies, please see this article.

Patients with diabetes

So as just discussed, there are multiple complications that can develop in an individual with diabetes directly related to one, two, or all three of the neuropathies that I just reviewed. Most of the time, patients with diabetes, especially if they've had it for a long period of time, will have all three of those neuropathies simultaneously, which even increases further their risk of developing a foot ulcer without proper care.

Frequency of Assessment

The American Diabetes Association (ADA) Standards of Medical Care in Diabetes recommends all patients with diabetes be assessed for diabetic peripheral neuropathy at diagnosis of Diabetes Mellitus type 2, 5 years after the diagnosis of Diabetes Mellitus type 1, and then at least annually for continued reassessment.

However, dependent on an individual patient's risk for foot ulcer formation, they may need to be reassessment more frequently. The International Working Group on the Diabetic Foot (IWGDF) developed an evidence-based risk stratification system which provides recommendations on how often more at risk patients with diabetes should be reassessed. The assignment of risk is based on the presence of (1) lack of protective sensation (LOPS), (2) Peripheral artery disease (PAD), (3) foot deformity, and (4) other high risk diagnoses or procedures (see Table 1 for details).

Table 1. IWGDF Risk of Foot Ulcer Formation

Risk Category	Risk of Ulcer Formation	Characteristics	Reassessment Frequence
0	Very low	No LOPS No PAD	once a year
1	Low	LOPS or PAD	once every 6-12 months
2	Moderate	LOPS and PAD OR LOPS and foot deformity Or PAD and foot deformity	once every 3-6 months
3	High	LOPS or PAD and one or more of the following: previous foot ulcer any lower-extremity amputation end-stage renal disease (ESRD)	once every 1-3 months

Above table is adapted from information provided in the IWGDF 2023 update.

Neuropathy Assessment Guidelines

The use of assessment guidelines or checklists is recommended to gather consistent objective assessments, especially when following a patient over multiple visits and across time.

Benefits of an assessment checklist include:

1. ability to establish trends and identify changes over time to guide inventions
2. facilitates communication among caregivers by providing objective and straight-forward information with consistent terminology
3. clearly identify risks for developing foot ulcers so that they can be addressed and monitored
4. opportunity to provide risk reduction education unique to the needs of the patient

Identifying an At-Risk Foot

Any person with diabetes is considered having an "at-risk foot" or "diabetic foot disease" if they present with the risk of developing foot ulceration and or infection. Signs that a person with diabetes is at risk of foot ulceration include (1) LOPS, and (2) diagnosis of PAD. By assessing for changes in LOPS, a rehabilitation or wound care professional can screen for changes in a patient's risk for the development of diabetic foot ulcers. Prevention of a foot ulcer is more efficient clinically and financially than foot ulcer treatment and closure. Please see section below on Foot Ulcer Prevention for more information.

Patients at a very low risk for foot ulceration (IWGDF risk 0, please see Table 1) should be screened at least annually.

Annual Foot Screening:

• Presence of active foot ulcer
• Assess for LOPS using one of the following methods:
  • Pressure perception: Semmes-Weinstein 5.07 or 10-gram monofilament
  • Vibration perception: 128-Hz tuning fork
  • If monofilament or tuning fork are not available, test tactile sensation: lightly touch the tips of the patient's toes with the tip of the clinician's index finger for 1–2 seconds
• Current vascular status: history of intermittent claudication, palpation of pedal pulses

ADD VIDEOS of monofilament testing and tuning fork testing

ADD IMAGE of foot monofilament testing sites

Comprehensive Examination Guidelines/Checklist

If a patient has either LOPS and/or PAD, they are at-risk of ulceration (IWGDF risk 1-3, please see Table 1), and a more comprehensive examination is indicated.

Detailed Medical and Social History

Below are listed foot specific medical history questions recommended by the IWGDF. As always, use clinical judgement and explore other topics as warranted.

Table 2.

Area of Questioning	Clinical Reasoning
Previous ulceration	Recurrence rate for diabetic foot ulcers is high, areas of previous ulceration need to be protected and monitored for potential re-ulceration. Patient and caregiver education is vital to maintain skin integrity - please see education section below for more details.
Previous amputation (minor or major)	Lower limb amputation causes biomechanics changes in the remaining limb and alters the patient's gait pattern. Ulceration risk will shift to other areas of the remaining limb due to changes in pressure during weight-bearing and gait.
ESRD
Prior foot inspection education
Social isolation
Poor access to healthcare
Financial constraints
Foot pain (at rest or with activity) or numbness
Mobility	This should include functional mobility, gait assessment, balance assessment, durable medical equipment (DME) recommendations, and fall risk screening. Neuropathy can affect a patient's ability to efficiently and safely complete necessary mobility, and increase their fall risk. Changes in gait dynamics can put patient at risk of developing new foot wounds due to changing pressures over their feet.
Other suggested interview topics
Claudication
Medication	Screen for medications or poly pharmacy which could affect balance

Above table is adapted from information provided in the IWGDF 2023 update and Diane Merwarth PT.

Special Topic: Fall risk assessment

So a fall risk assessment is important, especially with patients who are elderly or have had diabetes for a long period of time because their balance can change related to their proprioception and sensation and muscle strength and all of those things. So doing the balance impairment test using something like a modified Romberg is helpful to get that baseline and follow that over time. You're looking at their gait, especially the speed. If it's less than 0,6 metres per second, then it's too slow and they can have balance issues based on just walking too slow. And you might want to do some therapeutic interventions to help get a better pace during their walking. If they have visual impairment, that's going to affect their balance, of course. And as we know, vision is affected with diabetes pretty significantly. Do they have orthostatic hypotension, which may not be specific to a diabetic patient, but they could have orthostatic hypotension in addition to all of their other diabetes-related problems. And you need to know that to either have it treated or make sure the patient understands what's going on and how to accommodate to that.

You want to assess their home environment, looking for tripping hazards, the poor lighting, things that can cause them to lose their balance and fall that can be corrected for to decrease the risk of that.

Vascular Status

Although ischaemia is not considered to be a major cause of the neuropathic wound in a diabetic foot, it has been found to be a complication in over 65% of all individuals who develop a diabetic foot ulcer. Wound care professionals should refer patients back to their referring doctor for a more invasive vascular work-up if they suspect arterial compromise.

Table 3.

Assessment	Procedure	Clinical Reasoning
Pedal Pulses	Assess all pulses of the lower limb (femoral, popliteal, dorsalis pedis, posterior tibialis) for true clinical picture of vascular status. Palpation Doppler	20% of population does not have a dorsals pedis pulse Assess the entire limb to assess patient has adequate blood flow for wound healing and identify location of potential vascular compromise.
Capillary Refill	Capillary Refill Test	Tests the integrity of patient's arterial flow, which has affect on wound healing potential.
Skin Temperature	Clinician comparison by touch Infrared thermometer	Compare both feet Changes in temperature could indicate infection, Charcot exacerbation, vascular compromise Referring medical provided should be notified if there is a measured change in temperature over two consecutive days of 2.2 degrees Celsius or more
Ankle pressure and Ankle-Brachial Index (ABI) OR Toe pressure and Toe-Brachial Index	Measures the ratio between the systolic blood pressure of the lower limb and the upper limb, to assess for narrowing or blockages in the arteries in the legs	ABI found to not be reliable in patients with chronic diabetes due to arterial wall stiffening, recommend completion of toe-brachial index if available.

Above table is adapted from information provided in the IWGDF 2023 update and Diane Merwarth PT. ADD VIDEOS: LE pulses, doppler of LE

Skin Assessment

Table 4.

Assessment	Clinical Reasoning
Colour
Temperature	Please see Table 3 for details
Callus	Sign on abnormal pressures during gait. Must be removed as the callus itself can also act as a source of pressure, and to be able to visualise viable skin for proper assessment. Wounds can form under callus and cannot be assessed or treated until the callus is removed.
Oedema
Pre-ulcerative Signs	Pre-ulcerative signs are related to autonomic neuropathy, signs can include: Haemorrhage Decreased ability to sweat Dry cracked skin Fissures in skin

Above table is adapted from information provided in the IWGDF 2023 update and Diane Merwarth PT.

Bone/joint Assessment

1. Deformities
2. Excessive bony prominences
3. Decreased joint mobility (flexor hallucis or Achilles tightness,

foot stiffness)

check for deformities (e.g., claw or hammer toes), abnormally large bony prominences, or limited joint mobility. Examine the feet with the patient both lying down and standing up;

You're looking for toe deformities, the claw toes, hammer toes, cross-over toes, drifting toes. All of those malpositioned toes can cause an increased risk for developing wounds, not only just during the gait sequence, but because they make finding a pair of shoes to fit their foot extremely difficult and wearing a shoe that doesn't fit with those deformities can increase their risk of developing ulcers as well.

And then you want to look at the whole foot. You want to examine their arches. Do they have a really high arch? Do they have a flat foot? Do they have an extra wide foot? Are there excessive bony prominences like that first metatarsal head that causes a bunion, or the fifth metatarsal head? All of those structural changes that happen as the foot structures collapse, the muscle imbalance gets prolonged and exaggerated, and it causes lots of changes. The rocker bottom foot, which we will talk about more in the Charcot foot section of the module, and the extra wide foot. All of those increase the patient's risk of developing wounds because it's causing pressure on areas that are not used to sustaining pressure during gait.

You want to then make sure you examine and inspect all areas of the foot that aren't covered in all of the previous sections, a kind of complete overall foot assessment. And again, doing that bilaterally, if at all possible, is crucial. You want to look in the web spaces. Wounds can hide in the base of the web spaces, and no one will know they're there until they can become infected and create a problem that way. You're looking for excessively dry skin, or more important for wound development, primarily excessively macerated skin or the wound itself. If you open the web space and you find that the skin between the toes is extremely moist and starting to macerate, you can put something as simple as a dry gauze 2x2 or small gauze pad between the toes. That will wick the moisture away, prevent the skin-to-skin contact that accentuates that moisture retention in between the toes and help dry out the skin so that it doesn't continue to be macerated and eventually break down.

You want to be careful when you're inserting the gauze because it can be somewhat abrasive that you spread the toes open and put it down there without rubbing the skin that could potentially create a wound. But getting that gauze in there will really help. If they already have a wound or they are excessively wet and you're afraid that even a small gauze pad won't be enough to help absorb all that moisture, you can use some kind of a moisture wicking dressing product. The only one I'm familiar with is a transfer product that's made by Molnlycke. That wicks the moisture away and you can put the surface interface kind of in a horseshoe shape so that the tacky side is against the toes on both sides. It's a little challenging to get it down between the toes because it's sticky, but it really helps wick that moisture away. There may be other products on the market now, anything that helps wick the moisture to and away from the skin can help dry those web spaces out.

The same is true for the plantarflexor creases at the base of the toes. And with claw toes and hammer toes, sometimes those flexor creases, especially with claw toes, can be really tight and very closed in. So looking under there, a patient may remove his sock and inadvertently pull on the toe as he's removing the sock, not even realising that he's pulled on the toe because he has no sensation, and due to the inelasticity of the skin, actually causes a break at the base of the toe in that flexor crease. So again, looking for those, either the maceration from that skin-to-skin contact, from those really tight claw toes, or some kind of an accident, like pulling on the toe, but you're wanting to look for maceration or wounds. And again, you can insert dry gauze if it's just starting to macerate or you're concerned that it's too wet under there, or a wicking product if you have a wound to help get the moisture out of there and manage the wound at the same time.

The other thing that you want to look at is the integrity of the nails or the condition of the toenails in general. I know we've all seen patients with diabetes who come in with those really thick, jagged, rough nails that develop because of the changes in the keratin due to diabetes, as well as the vascular changes that are attributed to diabetes and the lack of care because the patient isn't able to care for their toenails. So you want to look at the integrity, look for minor fungal infections around them. You want to look at whether the patient is performing adequate hygiene, and if not, try to figure out why, if they're just not able to get to their foot, or they just haven't done it, so that you can work on education around that as well.

And then looking at the length and the shape of the nail is important. The risks are varied when it comes to the length of toenails. If they're just too long in general, then they have trouble fitting in a good shoe and that can put pressure on the toenail and cause problems. More often though, you'll start to see those really long toenails kind of curl under to the point where they're actually starting to put pressure against the plantar surface of the same toe. And eventually that can cause a wound with a prolonged pressure and the sharpness of the nail. Or, as we've seen very often, they can curve to the side and start putting pressure on an adjacent toe and again, cause it to break the skin or put pressure that will cause the skin to break down over time. So it's important to keep those toenails trimmed as best as possible.

You want to make sure that you advise the patient that they should never trim their own toenails. A family member should not do that either unless they have been specifically trained and determined to be competent to do so. If you are uncomfortable or don't feel competent to trim toenails, then it's important to refer them to a physician who does have the capability to do that, because the risk of that toenail is so great that trimming toenails is extremely important. If you're able to even just remove enough of the toenail so it's not putting pressure on the toe until you can get them referred, that is still helpful. If you are unable to do anything and you know that there's a risk of that toenail causing a wound, then you can at least put some kind of padding, a dry gauze pad, a thin foam pad that breaks that contact from the nail to the skin to try to give them time before any wound develops until they can get those toenails taken care of by the correct person.

The next area for assessment is range of motion. As I mentioned earlier, the stiffening of the tendons happens directly due to the influence of the chemical and cellular changes of diabetes. This causes a significant decrease in range of motion, which results in increased plantar pressure, because there isn't the flexibility of the foot during the gait sequence, which increases the risk of ulceration. The two primary areas that are the most serious and tend to be affected more frequently is the Achilles tendon shortening, which definitely decreases ankle dorsiflexion, and the flexor hallucis shortening, which causes the great toe to become stiff. And during propulsion and push off, there is less flexibility, and it puts point pressure right at the tip of the great toe, putting that at risk of developing a significant ulcer. You also can develop the overall stiffness of the foot, from the skin thickening and the tendons thickening, it decreases the overall elasticity or suppleness of the foot. And as I mentioned earlier, that really affects the foot's ability to function as a shock absorber during gait. And you lose that accommodation that happens when you're walking over irregular surfaces or changing from one surface to another. And once this thickening of the collagen in the skin and the tendons develops, you lose all of that accommodation. And that puts pressure in areas that aren't used to bearing pressure during gait, and significantly increases the risk of developing an ulcer. There are some therapeutic interventions which I'll talk about in more detail later, but the earlier that you can identify that the tendons are shortening or the skin is thickening, you can work on stretching and strengthening and passive and active range of motion to try to mitigate some of those changes, or at least delay the onset that can lead to that increased risk of developing a wound.

You also want to assess their proprioception, balance, gait, all of those functional components that are affected by the neuropathies that develop over time. So, proprioception has multiple components and it involves multiple senses. It's a very complex neurophysiologic process, but one of the ways to delineate different aspects of proprioception is to talk about the subsenses of proprioception. Things like whether it's active versus passive positioning, whether it's motion detection or direction discrimination, things that help the person know where their foot is or what part of their foot is doing what during gait is important to assess. You also want to think about are you assessing because you're trying to get something very specific from the interventions you're going to provide, which typically with a diabetic patient is not important. With your diabetic patient, you're trying to assess proprioception so that you can address those areas that are going to put them at risk for falling or developing wounds, those kinds of things. You're not trying to train them to become an elite athlete again, where the more sophisticated screening methods and assessment methods for proprioception are important. You're just looking at if they have an issue with where their foot is, then they're going to have a problem with gait and injuries to their foot subsequent to that.

There are a lot of studies in the literature talking about ways to assess for proprioception. There's not really a lot of consensus on whether one way is better than another when looking at proprioception. The various methods can be just touching the person on the plantar surface of their foot in different areas and have them identify where on the foot you're touching. Again, with a diabetic patient, that's difficult because they don't have sensation so they may not feel it to be able to identify where. You can passively move their toe or their foot in different directions and have them describe, are you moving it up or down to the side, to the inside, to the outside, those kinds of things. Those basic tests will probably enable you to identify that they have some kind of proprioception issue without going into a lot of elaborate testing with expensive equipment.

You're looking for the kinematic changes in the foot during gait, you know, there are foot deformities that can affect their motion during gait that cause biomechanical changes, as well as the biomechanical changes that may have occurred due to surgical interventions. Even amputation of a toe will biomechanically alter the foot, particularly if the tendons aren't repositioned to help prevent the drifting of the toes into the empty space or the altered muscle pull on the remaining toes based on the site of the amputation. Those all can cause biomechanical changes of the foot and change the gait pattern in general and put the patient at risk for wounds because of abnormal pressures in different areas. In addition, the decreased range of motion and the stiffness also affect the gait patterns and how they're moving on their feet during gait sequences.

Balance testing is also important. A lot of that also plays into proprioception. So you can kind of do some of those tests at the same time, but you're looking for balance changes that could be due to their lack of sensation. They don't know where their feet are to have the good base of support for balance, as well as the proprioceptive changes and the muscle weakness. So it's a complex series of things that you're trying to assess. And then doing a gait analysis, again, not to try to improve a person back to running or doing some kind of athletics, but to make them safe so that they have a good gait pattern that minimises their risks of wounds because of where they're putting pressure and how they're performing the gait sequence, as well as safety for tripping and balance and things like that.

Sensation Assessment

1. Assess LOPS if previously noted to be present

Cognitive Disorders

Of course, if they have dementia, they could have gait abnormalities and balance issues because they're just not aware of what they're doing. And so getting them into a facility, maybe if they have advanced dementia, so they're safe, or making sure there's always someone with them so that they're protected is important.

And then if they have symptoms of depression, that can also affect their balance, partly because they just don't care or they're not paying attention, and they can be at risk for falling and injuring themselves for that. So, you know, physical therapy, occupational therapy, doing home assessments, and trying to minimise all of the risks that can be related to falls and other issues is important. That home evaluation should also include looking for the safety features that are important for patients who don't have good balance or are ageing, including grab bars at the tub and the toilet, safety rails by stairs or any kind of abnormal surfaces that they can hold on to. Looking for hazards, just plain clutter, loose rugs on the floor, do they have to manage a step or go up and down stairs that they might forget about or miss and ways to identify them better by putting coloured tape or something to help them see those steps better might be important. And then overall cleanliness, not necessarily because you want to know how clean they are, but because those can present safety issues as well. And then watching them perform ADL (activities of daily living) and IADLs (instrumental activities of daily living) in their home environment to see, are they safe doing them? Do they have all of the safety features that would help them better enable them to perform the activities of daily living are important.

Footwear Assessment

1. Ill-fitting
2. Inadequate
3. Lacking

ill-fitting, inadequate, or lack of footwear;

Foot self-care Assessment

1. Excessive length/poor condition of toenails
2. Unwashed
3. Unclean socks
4. Superficial fungal infection

e.g. improperly cut toenails, unwashed feet ;

Physical limitations that may hinder foot self-care (e.g. visual acuity, obesity);

Foot care knowledge

Next, you want to examine the footwear. Do they have footwear? How does it fit? Is it too tight? Which, like I said before, is very common. Is it too loose? Which presents its own problems of pistoning in the shoe and causing friction and abrasion injuries that can lead to wounds. Is it inadequate? Is maybe there a hole in the sole of the shoe or the sole of the shoe is loose and it's flapping and that can cause a tripping hazard. As well as putting abnormal pressures wherever the sole is missing or it maybe folds under while they're walking. Or they don't have laces or velcro that secures the shoe to their foot and so it starts wobbling and they again piston inside the shoe and can cause problems that way, or do they not have any shoes, which is also a very common problem.

So if they don't have shoes, whatever your resources are to try to find them something until they can get into the best footwear that's important for them is better than nothing. So cast shoes or post-op shoes can help protect the base of the foot until they can get into something better at a minimum if you have access to those. Foot hygiene, as I said before, is also important. You can look and see if the foot has been washed, if their socks are clean or not, because that can create problems as well, especially if they wear damp socks a lot. As well as looking for any kind of superficial fungal infections on the skin. If hygiene is an issue, then it's important to find out why they aren't performing hygiene on their feet. Some patients can't reach their feet or they're afraid to do anything because of their nails or they might have a wound or a callus. And there's multiple reasons why, but it's important to find out why and then educate and help find someone who can perform that hygiene if the patient is unable to do so.

Patient Education/Caregiver Training

1. Physical limitations to self foot care
   1. Vision
   2. Obesity
   3. Decreased flexibility
2. Foot care knowledge

Foot Ulcer Prevention (MOVE TO THE END UNDER EDUCATION?)

ADD statistics on cost of treatment vs prevention

According to the IWGDF Prevention Guideline, there are five key elements to foot ulcer formation prevention:

1. Identify the person with an at-risk foot
2. Regularly inspect and examine the feet of a person at-risk for foot ulceration
3. Provide structured education for patients, their family and healthcare professionals
4. Encourage routine wearing of appropriate footwear
5. Treat risk factors for ulceration

Resources

Clinical Resources

Medication Review Resources:

https://www.cdc.gov/steadi/pdf/steadi-factsheet-medslinkedtofalls-508.pdf 65yo+

https://www.hhs.texas.gov/sites/default/files/documents/doing-business-with-hhs/provider-portal/QMP/Medications.pdf

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7243111/