Adult Acquired Flat Foot – PTTD

You've Seen People With Acquired Flat Foot (PTTD)

Posterior Tibial Tendon Dysfunction (PTTD) is a reasonably common condition particularly in people over the age of 55.

You’ve no doubt seen people at shopping centres with one foot which is so rolled in that it looks like they are walking on the inside of their ankle!

This is nearly always due to a failure of the Posterior Tibial Tendon.

The Posterior Tibial tendon connects the Tibialis Posterior muscle to the inside of the foot and is the tendon most responsible for lifting our arches off the ground.

For a variety of reasons this tendon can become overpowered, causing it to start to fail.

If left untreated this can lead to the tendon becoming weak, thin and longer than it was, allowing gravity to win and cause the inside (medial) of the foot to hit the floor – which is adult acquired flat foot.


A diagram of the bones of the lower leg including just the tibialis posterior tendon and muscle belly

Luckily there are treatments for Post Tibial tendon Dysfunction, and like with most things, the earlier you get treatment, the better the results.

Some people find the condition so crippling that they are forced to consider surgery just to allow them to stay on their feet.

At Dynamic Podiatry we are all about keeping you actively on your feet, so we will do whatever we can to prevent your condition from progressing if you start to suffer from Adult Acquired Flat Foot (PTTD).

In this article I will cover:

How Acquired Flat Foot Occurs

Acquired Flat Foot can arise from two main causes: having a congenital (at birth) weakness or imbalance, or a traumatic Incident which damages the tendon.

Some of the things which can be either genetic (inherited) or congenital (acquired at birth) include:

  • Ligamentous Laxity – we used to call this condition “double jointed,” but obviously there are no double joints. Some people just have ligaments which are more easily stretched than the average (there is no normal). What this then allows is for the foot structure to be overwhelmed by ground reaction forces (gravity) and the foot rolls in much more easily.
  • Feet which tend to roll in a lot more than they will roll out. In medical terms this is called a “medially deviated sub-talar joint axis.” What it really means is that the joints are aligned in a way that allows rolling in (pronating) much more easily than it allows rolling out (supinating).
  • Traumatic Incidents which can cause acquired flat foot include any type of injury which damages the tendons or ligaments which normally prevent the rolling in of the feet including the tibialis posterior tendon and the deltoid ligaments which are strong ligaments on the inside (medial) of the ankles.
Externally rotated feet
  • The alignment of other joints in the body can also make us more likely to get acquired flat foot.
    Including having knocked knees (genu valgum) or having hips which are quite externally rotated which causes the foot to be turned out and therefore it has to roll in to allow us to walk over the foot.

You'll Do Much Better If We Catch It Early

Like many conditions, the earlier we can start helping you with acquired flat foot, the better off you will tend to be.

If the tendon has not yet been permanently elongated or stretched, we can do things which will prevent it from getting further damaged and from going beyond the point of no return.

So what are the earliest stages of the condition?

  • pain along the inside(medial) of the shin bone and at the medial malleolus (see diagram),
  • an inability to go up on tip-toes,
  • a feeling of not being able to propel yourself forward as easily especially when going up stairs or hills.

PTTD is graded using a system from one to four. People who are at stage one are still in the elastic stage of the condition which means that the tendon can heal and go back to “normal.”


On the other end of the scale those with stage 4 PTTD are well into the plastic stage, meaning that the tendon has been permanently changed for the worse.

Our main goal is always to get you pain free or with as little pain as possible.


No matter what stage you are at a Podiatrist can still help you to live a more active lifestyle.

Non-surgical Treatment Options For PTTD

The main types of non-surgical treatments available can be broken down into two categories: prescribed exercises and in-shoe devices (orthotics).

Important Note: All the exercise information in this article is general in nature and does not replace advice from your health professional.

The most effective exercises which helped reduce the pain and improve the function of the tendon were progressive eccentric tendon-loading and calf-stretching program.

The eccentric tendon loading exercise is performed as follows:

  • stand on a low step or slightly raised platform on your tip toes, with your heel hanging over the edge,
  • Slowly bring your heel down until it is lower than the front of your foot,
  • raise your heel back up slowly until you are on tip-toes again.

Your podiatrist will let you know if these exercises are suitable for you and how often and how many reps you should do.

Calf stretching can be performed by leaning into a wall with your heel on the floor and your foot pointing directly to the wall.

Diagnosing Adult Acquired Flat Foot

In the video below you can see a patient with Stage 4 posterior tibial tendon dysfunction trying to go up onto tip toes.

Notice that his feet don’t roll out as they normally would.

Also he is unable to get his heels very far off the floor at all.

This is because the tibialis posterior tendon is likely ruptured and incapable of doing it’s job.

Orthotic Therapy for Adult Acquired Flat Foot

Custom foot orthotics are a crucial part of non-surgical treatment in most cases of adult acquired flat foot (PTTD) and are especially effective in reducing pain.

But before we even look at prescribing orthotics we will also do a shoe assessment. To make sure that the shoes you use for each activity aren’t making it even worse for the tendons and ligaments involved.

We may recommend that you buy new shoes for specific activities before going ahead with custom foot orthotics.

Reducing pain is crucial to getting you back into the activities that you love and that contribute to a happy, healthy life.

When podiatrists prescribe custom orthotics for this condition we make sure there is a lot of control at the back and the middle of the foot. It is particularly important to get the heel bone into a straighter position to reduce the pronatory (rolling in) forces which will bring the middle of the foot down to the ground.

Essentially they swing the alignment of the foot back in favour of the posterior tibial tendon so that it doesn’t go through as much tension and ultimately distortion from gravity.

In more severe cases where orthotics are much less effective, it may be necessary to prescribe an Ankle Foot orthosis (AFO) or even better – a custom foot orthosis incorporated into an AFO. The AFO has support up the medial and lateral (inside and outside) of the shins to avoid the ankle from rolling in with the foot.

To learn about orthotics and plantar fasciitis check out my earlier blog post here.

Surgical Options Available

Obviously we all want to avoid surgery if possible. But if conservative methods such as orthotics, shoes and exercises are not providing enough pain relief, and your normal daily activities are hampered, then it may be time to consider surgery.

As podiatrists we will often recommend that you get an opinion from a surgeon at any of the stages if we believe they may be able to help.

The things you need to ask if going for a surgical opinion are:

  • What will be the ultimate outcome of surgery? For example, do they think you will be able to get back to playing tennis (or any sport or activity) following the surgery?
  • Is surgery likely to reduce your pain?
  • Is surgery likely to prevent your PTTD from progressing to the next stage?
  • How long will you be out of action I.e. how long will you be totally non-weight bearing, and then how long semi-weight bearing and ultimately how long before you attain full recovery?
  • What are the risks involved in surgery?
  • And could you end up being worse off?

With that said the types of surgery available include repair of soft tissue including tendons and ligaments, and fusion of joints by placing screws, plates, nails or wires through the bones.

For severe cases of adult acquired flat foot it may be necessary to fuse joints round the ankle including the sub-talar joint or the talo-navicular joint.
Once the joints are fused, the tendons and ligaments around them are no longer under stress and therefore, pain usually resolves entirely.

You need to be aware that if joints are fused, then other soft tissues or joints may have increased stress and you may develop different injuries in the future. Fusion of joints in the feet or ankles will also have an effect on the other leg and foot, knees, hips and back joints.

Surgeons will take into account what stage of life you are at and what activities you do and weigh that against the pain you are suffering to decide which surgical option, if any, is best for you.

Long Term Outcomes With Acquired Flat Foot.

For many people with adult acquired flat foot the long term outcomes can be very good.

If caught early we can act to minimise any permanent damage done to tendons and ligements and bring balance back to you feet.

For people will more severe cases, there are now quite a few options such as AFOs with orthotics or surgical options, to ensure that you are still able to have a good quality of life.

If you would like help with your feet for whatever reason, call 3351 8878 to book an appointment or book online by clicking on the button below.

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