Acquired Flat Feet in Adults – What it is and how to treat the pain

What is Adult Acquired Flatfoot?

Do you look down at your feet and wonder why they look so flat, why they may be uncomfortable in shoes that have no support and be painful.

There is a common cause of adult acquired flatfoot which is posterior tibial tendon dysfunction. You may or may not have heard these terms before. In the podiatry circles it can be referred to as adult acquired flat foot, progressive flatfoot, tibialis posterior dysfunction, posterior tibial tendon dysfunction and posterior tibial tendon dysfunction in stage 1 and 2 then referred to adult acquired flatfoot in stage 3. For the purpose of this blog, it will be referred to as adult acquired flatfoot.

Adult acquired flatfoot is a gradual flatfoot deformation, which results in the dysfunction of tibialis posterior muscle being lost, tendon and associated soft tissue structures (ligaments) supporting the joints of the arch and rearfoot.

Function of the posterior tibial muscle

The tibialis posterior muscle resists pronation or rolling inwards on the foot but the main role of the tibialis posterior muscle is to invert the heel or lift the heel off the ground with contraction of the muscle from mid stance to end stage toe off during walking. This muscle movement allows the calf muscle to shift positions to inside of an imaginary axis and thereby making the midfoot more rigid during push off phase off walking and a more efficient transfer of stored energy in the leg for toe off and swing phase.

If there is dysfunction to the tibialis posterior it results in a less efficient manner whereby the calf muscle does not shift positions inside of the imaginary axis it moves laterally and outside of the axis and the calf muscles work harder to lift the heel off the ground to compensate for the dysfunction of posterior tibial muscle.

What are the common signs and symptoms of adult acquired flatfoot?

Stage 1:
· You may report very mild to moderate pain levels with a vague description of inside of the ankle area
· Exacerbated by exercise
· Not a noticeable collapse of the arch
· Person may be able to lift their heels off the ground without any trouble.
Stage 2:
· Can occur from a broad duration (few months to years)
· Ligamentous structures now affected
· Pain increases and is more specific to the course of the tendon.
· There is noticeable fatigue and weakness in the posterior tibial muscle and you may not be able to complete a heel raise.
· Increased collapse of the arch
· Heel is on an everted angle or turned outwards
· Too many toe signs (see picture on the right)
Stage 3:
· Pain still present on the inside of the ankle, but now on the outside of the foot due the heel being in a turned outwards constantly
· Foot position is fixed and rigid
· Secondary arthritic changes develop

What can a podiatrist do to help?

Stage 1 & Stage 2:
The goal is to prevent the progression of the foot deformity:

  • Imaging- Early in the disease radiographs may show normal findings and minimal changes. As the clinical deformity progresses radiographic characteristics change.
  • NSIAIDs- To control swelling and reduce pain.
  • Physical therapy- Stretching on the Achilles muscles and strengthening exercises for the Posterior Tibial muscle helps improve foot function and reduce pain.
    Exercises to help strengthen the posterior tibialis muscle
  • K-Taping- To provide support, lessen pain, decrease swelling and improve function.
  • Custom foot orthoses- To provide arch support and correct deformity
    Orthotics can help align the foot
  • Ankle Foot Orthoses- Generally when a patient has ligamentous damage and is unable to perform a single leg heel rise.
  • Footwear- Changing footwear to a high-topped shoe may provide stability through the ankle. Hiking boots can be a common suggestion as they provide support around the inside of the ankle.
  • Richie brace- Corrects forefoot to rearfoot deformities and corrects the tibia bone rotating.

Stage 3:
This stage is not passively correctable with the above-mentioned interventions and therefore may only help reduce pain and slow progression of the foot deformity. Surgery may be indicated at this stage.

The key point is getting this condition early and being aggressive with the treatments to prevent it getting to stage 3. If you see the pictures and you believe your feet need a thorough gait and biomechanical assessment from one of our podiatrists, don’t hesitate to book an appointment online or you can call us on (03) 9711 7562 and one of our team members can help you.

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