Adult Acquired Flat Foot: Why Your Arch Can Change Over Time and How Foot Orthoses May Help

Many people assume that flat feet are something you are born with. However, the shape and function of the foot can also change during adulthood.

You may notice that one foot looks flatter than it used to, your ankle appears to roll inwards, or you have developed pain around the inside of the ankle or arch. These changes may be associated with a condition commonly known as Adult Acquired Flat Foot.

The condition is now increasingly referred to by specialists as Progressive Collapsing Foot Deformity (PCFD).

At Keep Moving Podiatry, we assess how the foot is functioning, identify the mechanical changes contributing to your symptoms and, where appropriate, use foot orthoses (insoles) as part of a personalised treatment plan.

What is Adult Acquired Flat Foot?

Adult Acquired Flat Foot describes a change in the structure and function of the foot where the arch gradually lowers or collapses.

It can affect one or both feet, although sometimes the difference is much more noticeable on one side.

This is not simply a cosmetic change in the appearance of the foot. As the arch lowers, the position and movement of the foot and ankle can change. This may alter how forces are distributed through the foot when standing and walking.

The condition can involve several structures, including the posterior tibial tendon, ligaments supporting the arch and joints around the foot and ankle. Modern understanding therefore recognises that Adult Acquired Flat Foot is more complex than simply a problem with one tendon, which is one reason the term Progressive Collapsing Foot Deformity is increasingly used.

What symptoms might you notice?

Symptoms vary depending on the stage of the condition. You may notice:

• Pain or aching around the inside of the ankle or foot

• Pain underneath or around the arch

• Increasing flattening of the foot

• The ankle appearing to roll inwards

• The heel changing position

• One foot looking noticeably flatter than the other

• Tired or aching feet after prolonged standing or walking

• Difficulty walking longer distances

• Reduced confidence during physical activity

• Difficulty performing a single-leg heel raise

• Pain developing around the outside of the ankle as the condition progresses

Not everyone with a low arch requires treatment. The important question is whether the change in foot structure is associated with pain, reduced function or progressive mechanical changes.

Why does it happen?

There is not always one single cause.

The arch of the foot is supported by a combination of bones, joints, muscles, tendons and ligaments. If these structures become less effective at supporting the foot, its alignment can gradually change.

Age-related changes, previous injury, increased loading of the foot, weakness or dysfunction of supporting structures and other individual factors can all contribute.

For this reason, simply looking at whether someone has a "flat foot" is not enough. We need to understand how that particular foot is functioning.

Why is early assessment important?

If you have always had relatively flat feet and they are comfortable, this does not necessarily mean that something is wrong.

However, a foot that has recently started becoming flatter, particularly when accompanied by pain or weakness, deserves assessment.

Progressive Collapsing Foot Deformity can change over time, and the mechanical characteristics vary considerably between individuals.

Assessment allows us to determine what structures may be involved, how flexible the foot remains and whether conservative treatment may be appropriate.

How we assess Adult Acquired Flat Foot at Keep Moving Podiatry

At Keep Moving Podiatry, treatment starts with assessment rather than simply prescribing an insole.

During a biomechanical assessment, we may examine:

Foot posture and alignmentWe look at the position of the heel, arch, forefoot and ankle while you are standing.

Joint movementWe assess the mobility of relevant joints and whether the altered foot position remains flexible or has become more fixed.

Muscle and tendon functionParticular attention may be given to structures that help support and control the foot, including the posterior tibial tendon.

Functional testingTests such as heel raises can provide useful information about the ability of the foot and ankle to function under load.

Walking assessmentWhere appropriate, we assess how the foot behaves during walking rather than relying solely on its appearance when standing.

The objective is to understand why you are experiencing symptoms and what mechanical problem we are trying to manage.

How can foot orthoses help?

Foot orthoses are not simply pieces of material designed to "push the arch back up."

Their role is more sophisticated.

When appropriately prescribed, an orthosis can be designed to modify the forces acting on the foot and improve how load is distributed during standing and walking.

Depending on your individual assessment, an orthosis may be used to:

• Support the foot where appropriate

• Reduce excessive strain on painful or overloaded structures

• Modify loading around the inside of the foot and ankle

• Improve comfort during walking

• Help redistribute pressure and forces through the foot

• Improve tolerance for everyday activities

• Complement strengthening and rehabilitation exercises

The orthosis prescription should therefore be based on the individual's symptoms, foot structure and mechanical requirements rather than simply on the diagnosis of "flat feet."

Not every flat foot needs the same insole

This is particularly important.

Two people may both appear to have flat feet but have very different mechanical problems.

One person may require greater control around the rearfoot, while another may require support or load modification elsewhere in the foot. The flexibility of the deformity, location of pain, footwear and daily activities can also influence the prescription.

This is why at Keep Moving Podiatry we do not treat the appearance of the foot alone — we treat the individual mechanical problem identified during assessment.

A properly considered foot orthosis should have a clear clinical and mechanical objective.

Are orthoses a cure for Adult Acquired Flat Foot?

Foot orthoses should not be described as a cure or as something that will permanently rebuild the arch.

Their primary purpose is to help manage symptoms and modify the mechanical environment of the foot.

For some patients, orthoses may form part of a wider conservative treatment programme that can also include appropriate footwear advice, activity modification and strengthening or rehabilitation exercises.

More advanced or rigid deformities may require additional medical or orthopaedic assessment.

When should you have your feet assessed?

Consider arranging an assessment if you have noticed:

• A recent change in the shape of your foot

• One arch becoming progressively flatter

• Pain along the inside of your ankle or arch

• Increasing difficulty walking or standing

• Your ankle increasingly rolling inwards

• Persistent foot or ankle pain despite changing footwear

• Reduced strength when trying to rise onto your toes

The earlier we understand what is happening mechanically, the easier it is to discuss appropriate management options.

How Keep Moving Podiatry can help

At Keep Moving Podiatry, our approach is based on identifying the mechanical problem rather than simply providing an off-the-shelf solution.

Your assessment may include examination of foot and ankle movement, muscle and tendon function, foot posture and walking mechanics.

If foot orthoses are appropriate, the prescription is selected according to the findings of your assessment and the specific mechanical objective we are trying to achieve.

Our aim is simple:

Reduce pain, improve function and help you keep moving comfortably.

If you have noticed that your foot is becoming flatter, your ankle is rolling inwards or you are experiencing persistent arch or ankle pain, consider arranging a Biomechanical Foot Assessment with Keep Moving Podiatry.

Keep Moving Podiatry – Chorlton, ManchesterSpecialist assessment for foot pain, biomechanics and foot orthoses.

Book an appointment: www.keepmovingpodiatry.uk

This article is intended for general information and does not replace an individual clinical assessment or medical advice.