Pes Planus – Flat Feet

Pes Planus (Flat Feet)

Article by John Miller

Pes Planus

Flat Feet

What Is Pes Planus?

Pes planus or flat feet is a postural deformity relating to the medial longitudinal arch’s collapse or flattening. As seen in the image, pes planus results in the midfoot region pronating towards the ground, and in some cases touching the ground ultimately. Descriptions also include hyperpronation or overpronation. Although there are varying degrees of collapse, people can still live utterly pain-free with flat feet.

What Causes Flat Feet?

This condition can be congenital (e.g., birth) or acquired (e.g. adults, increased exposure to weight-bearing).

Congenital flat feet occur when someone is born with or predisposed to having a more flexible midfoot region resulting in pronation or collapsing of the arch. Ethnicity is a crucial factor surrounding flat feet, with the condition being more likely in certain indigenous cultures.

Acquired flat feet causes include a loss of active (e.g. intrinsic foot and ankle stabilisers) or passive support (ligamentous laxity, hypermobile joints). The lack of support during vigorous weight-bearing activities exaggerates the flatness. Muscular weakness in the ankle and arch stabilisers is the most common etiological factor for flat feet. Research suggests the tibialis posterior muscle is the most integral in stabilising the medial longitudinal arch via its insertion into the arch’s bony roof. When your arch stabilisers like this perform sub-optimally, the arch slowly pronates and flattens towards the ground when weight and force apply down through the foot.

How Do Flat Feet Progress?

pes planus

Flat feet slowly progress as you increase your feet’s exposure to weight-bearing activities. The two most common progressions from flat feet are foot deformities and bony stress injuries.

In the active person, hyperpronation alters the load transference up through the leg and can cause stress responses such as shin splints and, in the worst case, stress fractures.

At the opposite end, the bones through your foot are also exposed to altered loads, potentially causing a bunion. As seen in the image, the midfoot pronation and collapse of the arch change the force’s line to the outside of the first metatarsal (from green to red), creating the bony protrusion. As the metatarsal head pushes outwards, the rest of the big toe glides inwards, further accentuating the bunion.

What Conditions Can Flat Feet Cause?

Without an appropriate rehabilitation program and continuing active or passive instability, structures surrounding or supporting the arch can load inappropriately and unsafely to cause compounding problems. The most common compounding problems are listed below:

Tibialis Posterior Tendinopathy

Your tibialis posterior muscle is a vital arch stabiliser. However, if weakness is apparent and the tissue is overloaded, tendinopathy or muscle injury can occur. More info: Tibialis Posterior Tendinopathy

Plantar Fasciopathy

Better known as plantar fasciitis, plantar fasciopathy can develop due to altered arch biomechanics and increasing midfoot pronation. The plantar fascia is overloaded while trying to compensate for this continuing loss of arch integrity.

Medial Tibial Stress Syndrome or “Shin Splints”

The excessive pronation can cause the tibialis posterior or soleus muscle to apply altered stress to the tibia’s inner aspect—this unreasonable motion results in medial tibial stress syndromeshin splints or tibia stress fractures.

Achilles Tendinopathy

Flat feet can cause the medial aspect of your Achilles tendon may compensate for the increased motion of the midfoot and exposure to abnormal loads leading to injury. Achilles tendinopathy or its subgroup Achilles tendinitis may be the result.

Patellofemoral Pain Syndrome

Your patella or “kneecap” is commonly affected due to its altered translation during movement. The ankle and knee rotational changes can push the kneecap in the wrong direction, causing anterior knee pain—more info: patellofemoral pain syndrome.

Biomechanical Factors

Excessive or overpronation of the midfoot can cause a cascade effect through the ankle, knee, and hip via inducing tibial and femoral rotation changes and altering these joints’ standard dynamic control. These changes, although sometimes subtle, can predispose your knee and hip joints to increased instability and an increased likelihood of acute trauma.

How are Flat Feet Diagnosed?

The Foot Posture Index (FPI) is an observational tool that constitutes six items to analyse your static standing posture from 3 different angles. The FPI can assist your physiotherapist in diagnosing flat feet or pes planus. However, your diagnosis should not rely entirely on this one index.

Due to problems most commonly arising in weight-bearing activities, your physiotherapist will also observe you conducting numerous single leg tasks to investigate your overall dynamic control, from your foot and ankle to your hips. Tests will include activities that challenge your strength, endurance, proprioception, and balance. The main focus will be identifying any active insufficiencies through your arch and its’ respective stabilisers.

A weight-bearing X-ray may investigate the integrity and dynamic control of the arch’s specific joints under stress and load in some cases.

Don’t hesitate to get in touch with your foot physiotherapist for advice specific to your pes planes.

Pes Planus Treatment

Treatment for pes planus can vary, chiefly considering the broad etiological factors. Below is a range of treatment directions focusing primarily on improving the foot and ankle’s active stabilisation to endeavour to correct the flat feet deformity.

Restore Intrinsic Muscle Control and Foot Arch Biomechanics

Your foot arch’s important intrinsic plantar muscles, which may be weak or have poor endurance, require retraining. These foot muscles have a vital role in dynamically stabilising your foot’s base plus preventing overpronation of the midfoot and loading through your plantar fascia.

Dynamic Foot Posture Exercises

Any deficiencies will be an essential component of your rehabilitation. Your physiotherapist is an expert in the assessment and correction of your dynamic foot control. They will help you restore your normal foot biomechanics and provide you with foot stabilisation exercises to alleviate any deficiencies.

Passive Arch Support / Orthotics

After your biomechanical assessment, a soft temporary orthotic may help provide protection and relief through over-loaded structures. If your physiotherapist deems an orthotic will benefit from long-term use, they may refer you to a podiatrist for a custom-made orthotic. The good news is that most flat feet sufferers will not need permanent passive arch support such as an orthotic.

Restore Normal Calf & Leg Muscle Control

You may find it challenging to comprehend, but all of your leg (calf, thigh and hip) muscles play an essential role in controlling your ankle position and foot arch mechanics. Your physiotherapist will assess your leg muscle function. They’ll provide you with the necessary treatment or exercises to correct any ankle, knee or hip stabiliser insufficiency. Ask your physiotherapist for more specific advice.

Improve Your Running and Landing Technique

If your flat feet or compounding problems of the ankle or leg exacerbate with sport or running, which place enormous forces through these areas, a good physiotherapist will be able to analyse your running and landing technique.

Based on that assessment, treatment provided to you will help with technique correction and preventative strategies to reduce the likelihood of injury recurrence.

Return to Sport or Work

Depending on the demands of your chosen sport or your job, you may require specific sport-specific or work-specific exercises and a progressed training regime to enable a safe and injury-free return to your chosen sport or employment. While flat feet themselves can be pain-free, for some people, the pain it causes can hamper their working and active life. Specific focus will apply to control your foot arch through particular activities that are causing you discomfort.

Your physiotherapist will discuss your goals, time frames and training schedules with you to optimise your complete and triumphant return to sport or work. Work-related injuries will often require a discussion between your doctor, rehabilitation counsellor or employer.

Footwear Analysis

Sometimes it is poorly designed footwear that can predispose you to acquire flat feet or an associated injury. If you do suffer pain or discomfort that is impacting your active lifestyle, you should seek the professional advice of your healthcare practitioner to assist your ability to determine the best footwear for your feet.

For more specific advice about your pes planus, please contact your PhysioWorks physiotherapist.