Pes Planus (Flat Feet): Causes, Symptoms, and How We Can Help
- staystrongtherapy
- Jun 30
- 5 min read
All information in this blog is supported by peer-reviewed research. There is currently no dedicated NICE guideline for this condition, so current evidence is used throughout. Reference numbers appear throughout, with the full list at the bottom of the page.
What Is Pes Planus?
Pes planus, commonly known as flat feet, is a foot deformity defined by the loss of the medial longitudinal arch of the foot, the inner arch that normally lifts slightly off the ground when standing, with the arch contacting or nearly contacting the ground instead. ¹ The arch normally serves as an adaptive, flexible base that helps dissipate weight-bearing forces as you walk. ¹
Pes planus can be congenital (present from birth, which is genuinely normal in infants) or acquired later in life. ¹ It's worth knowing that pes planus is often asymptomatic, but when symptomatic, it can alter the biomechanics of the lower limb and lumbar spine, increasing the risk of pain and injury, not just in the foot itself, but in the ankle, knees, and hips too. ¹
Why Does It Develop?
In children, flat feet are typically a normal part of development, since arches form gradually through early childhood, and all babies are born with flat feet. ² Where flat feet persist or develop in adulthood (sometimes called fallen arches), this usually relates to an underlying contributing factor. ²
A key structure involved in adult-acquired flat feet is the posterior tibial tendon (PTT), which runs along the inside of the ankle and plays a central role in supporting the arch. Dysfunction of this tendon is a recognised driver of progressive flat foot deformity in adults. ³
Common Signs and Symptoms
Foot pain, commonly along the inner arch or ankle ⁴
Swelling, particularly around the inside of the ankle ⁴
Stiffness affecting the arch, sometimes spreading to the legs and back ⁵
Ankle instability, which can affect walking and balance ⁶
A visible lack of arch when standing, sometimes with the whole sole of the foot touching the ground
Risk Factors
Posterior tibial tendon dysfunction, a key driver of progressive, acquired flat foot in adults ³
Reduced strength in the posterior tibial muscle, alongside related kinetic chain weakness ³
Hip and gluteal weakness, research has found that combined intrinsic foot and gluteal strengthening, alongside hip-focused neuromuscular training, was effective for improving arch posture and lower limb alignment, suggesting hip function genuinely matters here too ³
Underlying connective tissue laxity or hypermobility, recognised as a contributing factor, particularly relevant in flexible (rather than rigid) flat foot presentations ⁷
Ageing and cumulative tendon wear, contributing to acquired flat foot developing later in life
Family history and congenital factors, since the structural tendency toward a lower arch can run in families
When Should You Be Concerned? Red Flags to Watch For
Please seek medical assessment if you experience:
Sudden, significant pain or swelling around the inner ankle, particularly if accompanied by an inability to rise onto your toes (possible posterior tibial tendon rupture)
A rapidly progressive change in foot shape
Numbness or tingling spreading into the foot
Signs of infection, such as redness, warmth, or fever
How Is It Diagnosed?
Clinical and radiographic evaluation are necessary to determine the extent and flexibility of the deformity. ¹ X-rays can reveal structural deformities, misalignment, or arthritis, while MRI or CT scanning may be used for soft tissue assessment, particularly of the posterior tibial tendon, where relevant. ⁸
Myths vs Facts
"Flat feet always need treatment." Not at all. Pes planus is often genuinely asymptomatic, and the general guidance for children specifically is that they usually outgrow the condition without treatment being necessary. ²
"Orthotics alone will fix the underlying problem." Orthotics are genuinely helpful, but the strongest evidence points toward combining orthotic management with progressive strengthening of both the foot and ankle, and the hip and pelvic musculature, rather than relying on orthotics in isolation. ³
"There's nothing I can do with exercise for this." The evidence increasingly disagrees. A 2024 network meta-analysis on exercise interventions for this condition highlighted the genuine benefit of kinetic-chain strengthening approaches, working the whole lower limb rather than just the foot itself. ³
How We Can Help
Initial treatment for posterior tibial tendon dysfunction and related flat foot presentations typically includes non-operative approaches such as activity modification and anti-inflammatory measures, with structured exercise forming a central, well-evidenced part of conservative management. ³
Osteopathic manual techniques and manual therapy: addressing restriction and compensatory tension through the foot, ankle, hip, and lower back, given the recognised connection between flat foot mechanics and broader lower limb and spinal alignment.
Deep tissue and sports massage: targeted soft tissue work for the posterior tibial muscle, calf, and surrounding lower limb structures.
Medical acupuncture and cupping: used as part of a broader treatment plan to support pain management where flat feet are contributing to discomfort.
Footwear and orthotic guidance: motion-control footwear can help improve stability, and orthotic management combined with appropriate exercise has shown the most effective outcomes for foot function in current research. ⁶ ³
Exercise: The Evidence-Based Approach
This is genuinely one of the more interesting and specific evidence bases we cover, with research identifying which combinations of exercise produce the best outcomes.
Posterior tibial strengthening combined with iliopsoas (hip flexor) stretching and towel curl exercises: research has found this specific combination produces the greatest improvement in navicular drop, a key measure of arch collapse under load. ³
Hip-focused neuromuscular training: shown to be effective for improving arch posture and overall lower limb alignment, reinforcing that flat foot treatment genuinely benefits from looking beyond the foot alone. ³
Combined intrinsic foot and gluteal strengthening: another evidence-supported combination for improving arch support and alignment. ³
Orthosis combined with stretching and eccentric posterior tibial tendon strengthening: found to be the most effective overall approach specifically for improving foot function. ³
Balance training and gait re-education: supports overall stability and movement quality. ⁴
A genuinely useful, practical detail from the research: exercise protocols lasting at least 6 to 12 weeks, performed three or more times a week, were associated with the best outcomes, reinforcing that consistency over a meaningful period of time matters considerably. ³
What to Expect at Your First Appointment
We will take a thorough history and carry out a hands-on assessment of your foot, ankle, hip, and overall lower limb alignment, including assessing the flexibility of your flat foot presentation. We will explain clearly what we find and build a progressive, evidence-based treatment plan combining appropriate orthotic or footwear advice with a structured strengthening programme addressing the foot, ankle, and hip together.
Frequently Asked Questions
Do I need a scan? Not always. Clinical assessment is often sufficient, with imaging considered where structural deformity, tendon involvement, or arthritis needs to be assessed more closely.
Will I need surgery? Most people don't. Conservative treatment, combining orthotics with structured exercise, is the recommended first-line approach, with surgery reserved for more severe or refractory cases.
Why are you working on my hip if my problem is in my foot? Because the evidence genuinely supports this, hip-focused strengthening has been shown to improve arch posture and overall lower limb alignment, not just exercises targeting the foot in isolation.
How long will treatment take? Research suggests exercise protocols of at least 6 to 12 weeks, performed three or more times weekly, produce the best results, so consistency over this kind of timeframe is genuinely important.
Recognise these symptoms? Get in touch using the contact form and we will assess and build the right treatment plan for you.
References
Pes Planus. PubMed. Available at: https://pubmed.ncbi.nlm.nih.gov/28613553/
Flat feet: Symptoms, exercises, diagnosis, and treatment. Medical News Today. Available at: https://www.medicalnewstoday.com/articles/168608
Pes Planus/Adult Acquired Flatfoot Deformity. PM&R KnowledgeNow. Available at: https://now.aapmr.org/pes-planuscavus/
Flatfoot (Pes Planus): A Comprehensive Overview of Causes, Diagnosis, and Management. Clinical Research on Foot & Ankle. 2025;13:623. Available at: https://www.omicsonline.org/open-access-pdfs/flatfoot-pes-planus-a-comprehensive-overview-of-causes-diagnosis-and-management.pdf
Flat feet: Symptoms, exercises, diagnosis, and treatment. Medical News Today. Available at: https://www.medicalnewstoday.com/articles/168608
Flat Feet (Pes Planus): Types, Symptoms & Treatment. Cleveland Clinic. Available at: https://my.clevelandclinic.org/health/diseases/flat-feet-pes-planus
Exploration of Flexible Pes Planus as a Potential Risk Factor for Cardiac Pathologies in Pediatric Cases. PMC. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10538805/
Flatfoot (Pes Planus): A Comprehensive Overview of Causes, Diagnosis, and Management. Clinical Research on Foot & Ankle. 2025. Available at: https://www.omicsonline.org/open-access-pdfs/flatfoot-pes-planus-a-comprehensive-overview-of-causes-diagnosis-and-management.pdf
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