Foot Posture Index (FPI-6)

What is the Foot Posture Index (FPI-6)?

Theis a diagnostic tool designed to gauge foot posture. It aims to check if a foot has a neutral posture (which is ideal) or if it is:

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• Pronated, which means the person’s foot is rolled inward, whether they are standing or walking,
• or Supinated, which means that the foot is rolled outward, also while standing or walking.

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The index has six sections, hence its short-form title of FPI-6. These sections are divided into two parts:

1. Rearfoot - This measures the palpability of the talar head, the curves above and below the malleoli, and the inversion or eversion of the calcaneal.
2. Forefoot - This is for measuring the foot’s talonavicular congruence, the height of the medial arch, and the adduction of the forefoot.

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The clinician using this index will have the patient stand still so they can observe all six of these aspects. The index has set designations, so they only need to mark which ones apply to the patient based on their observations. Each designation has an assigned score, and the sum will dictate if the foot’s posture is normal, pronated/overpronated, or supinated/oversupinated.

Check out this video on our Foot Pain Chart to see how similar assessments are performed:

How to use the Foot Posture Index (FPI-6)

Before doing anything else, the clinician using the Foot Posture Index should do the following:

• Have their patient stand still. Their arms need to be on the side, and they must be looking straight ahead.
• While standing, they need to assume a relaxed standing position.
• Optional: the clinician can have the patient march on the spot before assuming a relaxed standing position.
• Tell the patient not to swivel or move because doing so might affect their observations during the assessment because swiveling or moving will affect foot posture.
• Once the patient stands still in a relaxed position, the clinician will observe the posterior aspects of the leg and foot for a few minutes. This assessment usually takes two minutes to accomplish, but the clinician can take longer if they need to.

When assessing the feet, the clinician must do the following:

• Palpate the talar head to see where it is.
• Check what the curves above and below the malleoli are like. Are they straight, convex, concave, or equal?
• Measure the degree of the calcaneal’s inversion or eversion
• Check if the talonavicular congruence is concave, flat, or bulging
• Check if the medial arch height is angled towards the posterior end, if it’s concentrically curved, or if the arc is low and flat.
• And last, to see if the medial and lateral toes are equally visible, if the medial toes are more visible than the lateral toes, or if the lateral toes are more visible than the medial toes.

While observing, they need to pick any one of the designations set for each section.

How to score the Foot Posture Index (FPI-6)

Scoring the Foot Posture Index (FPI-6) is easy because it requires very little effort! That’s because the scores are already set per designation, so you only need to calculate the sum of all scores. Here are the designations for your reference:

Rearfoot

1. Talar head palpation

• Talar head is palpable on the lateral side, but not on the medial side = -2
• Talar head is palpable on the lateral side, but slightly palpable on medial side = -1
• Talar head is equally palpable on lateral and medial side = 0
• Talar head is palpable on the medial side, but slightly palpable on the lateral side = 1
• Talar head is palpable on the medial side, but not on the lateral side = 2

2. Curves above and below the malleoli

• Curve below the malleolus is either straight or convex = -2
• Curve below the malleolus is concave but is flatter / more shallow than the curve above the malleolus = -1
• Both infra and supra malleolar curves are roughly equal = 0
• Curve below the malleolus is more concave than the curve above the malleolus = 1
• Curve below the malleolus is markedly more concave than the curve above the malleolus = 2

3. Calcaneal inversion/eversion

• More than an estimated 5-degree inverted (varus) = -2
• Between vertical and an estimated 5-degree inverted (varus) = -1
• Vertical = 0
• Between vertical and an estimated 5-degree everted (valgus) = 1
• More than an estimated 5-degree everted (valgus) = 2

Forefoot

1. Talonavicular congruence

• Area of TNJ is markedly concave = -2
• Area of TNJ is slightly but definitely concave = -1
• Area of TNJ is flat = 0
• Area of TNJ is bulging slightly = 1
• Area of TNJ is bulging markedly = 2

2. Medial arch height

• Arch is high and acutely angled towards the posterior end of the medial arch = -2
• Arch is moderately high and slightly acute posteriorly = -1
• Arch height is normal and concentrically curved = 0
• Arch is lowered with some flattening in the central portion = 1
• Arch is very low with severe flattening in the central portion (arch is making ground contact) = 2

3. Forefoot adduction

• No lateral toes are visible, but the medial toes are clearly visible = -2
• Medial toes are clearly more visible than the lateral toes = -1
• Medial and lateral toes are equally visible = 0
• Lateral toes are clearly more visible than the medial toes = 1
• No medial toes are visible, but the lateral toes are clearly visible = 2

You simply need to pick your designations based on your observations. Then, just add up the scores.

Here are the score ranges to take note of:

• 0 to 5 = Normal
• 6 to 9 = Pronated
• 10+ = Highly pronated
• -1 to -4 = Supinated
• -5 to -12 = Highly supinated

When is it best to use the Foot Posture Index (FPI-6)?

Earlier, we mentioned the Foot Posture Index (FPI6) is a diagnostic tool. To be more specific, it doesn’t exactly diagnose anything but helps assess the foot posture to determine what particular assessments should be conducted moving forward. The Foot Posture Index (FPI-6) is normally included in comprehensive examinations.

This is because it shouldn’t be used as the sole assessment to determine what foot problem the patient is dealing with. Based on the index results, you can correlate the observations and scores to certain foot conditions like Plantar Fasciitis, Achilles Tendonitis, and more. The next step is to determine what other assessments should be conducted.

So, for example, the results indicate that the patient is at risk of developing Plantar Fasciitis. This means the next assessment should be meant for assessing that foot condition, like the Windlass Test. Then, the following tests should be imaging tests to confirm it and make an official diagnosis.

The Foot Posture Index (FPI-6) is also used for orthotic prescriptions, so providers of orthoses can tailor-fit certain equipment and accessories to the patient based on the findings to make sure that the patient will find them to be comfortable when they receive them.

What are the benefits of using the Foot Posture Index (FPI-6)?

It is an inexpensive but comprehensive tool to use.

The Foot Posture Index (FPI-6) doesn’t require any special equipment from the healthcare professional. All they need to do is make their patient stand still and observe their feet for a few minutes, and that’s it.

Even if it sounds so simple, it’s a great tool to include in any podiatrist’s roster of clinical assessments. It asks clinicians to observe six aspects of a person’s foot to gauge if the foot has good posture or is (too) pronated or (too) supinated. By doing so, clinicians using the index can determine what to do next for the patient.

It can help professionals determine how to assess and treat a patient.

Speaking of determining what to do next for the patient, the results of the Foot Posture Index (FPI-6) can be used to chart the treatment path of the patient by first helping professionals determine what set of tests should be conducted. These tests should determine the possibility of certain foot conditions that the patient might already have.

The index does the same, but certain assessments, like the Windlass Test, can narrow things down. Imaging tests will then confirm all the results, and an official diagnosis can be made after. Throughout this process, they will also know what to add to a tailor-fitted treatment plan for the patient based on all the results.

The results can even be used to help orthoses dispensers to customize equipment for the patient.

It can serve as a good monitoring tool.

Once you’ve implemented a treatment plan for your patient, it’s only natural to want to know how they are doing. During routine check-ups, you can use the Foot Posture Index (FPI-6) to see if they are getting better. If their scores show that their feet are slowly regaining good posture, then it’s safe to assume that the patient is getting better and your treatment plan is effective.

If the results show the same or if their foot posture is somehow getting worse, then you might want to tweak your treatment plan and see if the changes will work.