Flat feet (Pes planus): causes, symptoms and treatment

What is a flat foot?

Flat feet is the name given to the significant lowering of the inner longitudinal arch. The foot lies flatter, the heel often turns inwards (valgus position), and the toes sometimes point more outwards when viewed from behind (“too many toes” sign). A distinction is made between flexible flat feet, in which the arch partially comes back when standing on toes, and rigid flat feet, which remain flattened even under load and unloading.

• Flexible flatfoot: often harmless, especially in children; Arch appears in toe stand/relief.
• Rigdier flat foot: vault remains flat; more often painful, e.g. B. in tarsal coalition or osteoarthritis.
• Acquired flatfoot (adulthood): usually the result of dysfunction of the tibialis posterior tendon, ligament laxity or osteoarthritis.

It is important to distinguish it from the arched arched foot: With the arched arched foot, the arch has sunk and the heel bends inwards; With pronounced flat feet, the longitudinal arch is almost eliminated.

Anatomy and biomechanics of the arch of the foot

The medial longitudinal arch of the foot is supported by bones (including scaphoid, sphenoid), ligaments (spring ligament/lig. calcaneonaviculare plantare), the plantar fascia and muscles (particularly the tibialis posterior muscle). It serves as a shock absorber and energy store when walking and running.

• M. tibialis posterior: central dynamic support of the longitudinal arch.
• Plantar fascia: Tight band under the foot, passively stabilizes.
• Calcaneus and hindfoot axis: influences load distribution and pronation.

If overpronation occurs and the arch support weakens, the foot flattens. In the long term, incorrect strain can affect the knees, hips and back.

Typical symptoms

• Pain on the inner edge of the foot, on the inner ankle or on the sole of the foot (plantar side).
• Pain from fatigue after standing/walking for a long time, later also possible at rest.
• Pressure points on the inside, problems in flat or soft shoes.
• Pulling pain in the lower leg (tibialis posterior tendon), occasionally shin splints.
• Secondary complaints: Achilles tendon, knee (medial overload), hip/back.

Children with flexible flat feet are often symptom-free. Pain, one-sidedness or rigidity are warning signs and should be clarified.

Causes and risk factors

• Childish, flexible flat feet: a common normal variant in development.
• Acquired flatfoot: dysfunction or degeneration of the tibialis posterior tendon (e.g. overuse, age, systemic diseases).
• Ligament laxity, weak connective tissue, obesity, prolonged standing/walking in unfavorable footwear.
• Forefoot misalignments (e.g. splayfoot) and axial deviations.
• Osteoarthritis/inflammation in the hindfoot area, rheumatic diseases.
• Rigid flatfoot: e.g. B. through tarsal coalition (bone/ligament-like connection).
• Injuries/fractures with malunion, neuropathies (e.g. in diabetes).

Diagnosis in orthopedic practice

The diagnosis is based on a clinical examination and – depending on the findings – imaging procedures. What is crucial is the distinction between flexible and rigid flat feet and the assessment of the severity and cause.

• Anamnesis: localization of pain, resilience, shoes, sport, previous injuries, systemic diseases.
• Inspection & functional test: hindfoot axis, standing/gait pattern, one-legged toe stand, “too many toes” sign.
• Stretch tests (e.g. calf muscles/Silfverskiöld test), tibialis posterior strength test.
• Footprint, pedographic measurements, if necessary video gait analysis.
• X-ray while standing to assess the axis and joints; Ultrasound of the tibialis posterior tendon.
• MRI/CT if tendon damage, coalitions or extent of osteoarthritis are suspected.

Differential diagnoses include: Arches, pes valgus, tarsal coalition, cavus foot variants as well as inflammatory or neurological causes.

Conservative treatment – ​​the central building block

Most flat feet can be easily managed without surgery. The aim is to reduce pain, improve function and slow possible progression. We put together the therapy individually.

• Education & activity adjustment: load control, breaks, alternation between sitting and walking.
• Shoe advice: firm heel support (stable heel cap), moderate heel (“drop”), sufficient volume in the forefoot.
• Insoles supply: supportive insoles with medial longitudinal arch support, depending on the findings also heel support; Regular fit checks.
• Physiotherapy: Strengthening (especially tibialis posterior, short foot muscles), stretching (calf/plantar fascia), sensorimotor training.
• Taping/temporary orthoses: to relieve painful phases.
• Weight management: even moderate reductions significantly reduce the strain on the feet.
• Pain management: cooling, possibly short-term NSAIDs - after medical consideration.

In individual cases with tendinous symptoms, infiltrations can be discussed. Cortisone in or on the tibialis posterior tendon is viewed critically because of possible tendon weakening. Biological processes (e.g. PRP) are sometimes used; The evidence is limited, and any benefit should be weighed and clarified on an individual basis.

Exercises for flat feet: targeted and suitable for everyday use

Regular practice improves muscular arch support and rearfoot control. Start in a way that is adapted to the pain, build up slowly and let the technique guide you initially.

Important: quality over quantity. Pain that goes beyond muscle soreness is a signal to adapt.

Insoles, shoes and orthoses

The right combination of shoe and insole relieves pressure on the longitudinal arch and improves hindfoot guidance.

• Insoles: supportive but not rigid; individual adaptation and control under everyday stress.
• Shoes: stable rear foot, torsion-resistant sole, moderate heel; enough space in the forefoot.
• Sport: depending on the discipline, test stable shoes/pronation support; Evaluate insoles in sports shoes separately.
• AFO/ankle-foot orthoses: for severe acquired flat feet (PTTD) for axle guidance - use for a limited time.

When does an operation make sense?

Surgery is considered if, despite consistent conservative therapy, relevant symptoms, instability or a progressive deformity persist. The choice of procedure depends on the cause, severity, age, activity level and comorbidities.

• Soft tissue reconstruction: tendon suture/transfer (e.g. tibialis posterior, flexor digitorum longus) in PTTD.
• Bone corrections: medializing heel bone osteotomy (calcaneus), lengthening osteotomy (Evans), wedge osteotomy (Cotton) for arch positioning.
• Calf muscle/Achilles tendon lengthening with a shortened chain.
• Arthrorisis (particularly in selected, young patients) for hindfoot alignment.
• Arthrodesis (joint stiffening) for rigid misalignment/arthrosis.

After surgery, immobilization, partial weight-bearing and physiotherapy are required; recovery takes weeks to months depending on the procedure. Risks and benefits are discussed in detail in advance. Guaranteed success cannot be guaranteed.

Special features: children vs. adults

Children often have flexible, pain-free flat feet - usually a normal variant that stabilizes with development. There is a need for therapy especially in cases of pain, rigidity, one-sidedness or functional limitations.

• Children: lots of age-appropriate exercise, barefoot on varied surfaces, insoles for complaints and functional deficits.
• Warning signs: rigid flat feet, significant asymmetry, persistent pain - seek medical advice (e.g. tarsal coalition).
• Adults: more commonly acquired flat feet due to tendon/ligament insufficiency; Early conservative stabilization reduces subsequent symptoms.

Everyday life, work and sport

• Control load: regulate standing/walking phases, incorporate short compensatory movements.
• Shoe rotation: alternate different, suitable shoes; Use deposits consistently.
• Workplace: suitable mats if you stand a lot, micro breaks; Incorporate foot activation if you sit a lot.
• Sport: start gently on the joints (cycling, swimming, walking). Running training with appropriate footwear and technique development.
• Barefoot: dosed on soft, varied surfaces; If there is a pronounced misalignment, be careful and guided.

Course, prognosis and prevention

The process is individual. Many flexible flat feet remain symptom-free. In acquired flat feet, symptoms can progress as tendons and ligaments continue to give way. Consistent conservative measures improve function and can have a positive influence on the course.

• Early diagnosis and treatment increase the chance of avoiding surgery.
• Regularly check insoles and shoes, especially if you change weight or change careers.
• Stay muscularly active: maintain exercises, balance and stretches.
• Address risk factors: weight, footwear, training management.

When should I see a doctor?

• Persistent or increasing pain on the inner edge of the foot/inner ankle.
• New swelling, redness or significant misalignment.
• Stiffness of the hindfoot, lack of toe position, feeling of instability.
• Unilateral symptoms in children or sudden deterioration.
• Concomitant illnesses such as rheumatism or diabetes with foot problems.

If you experience acute, severe pain, numbness, severe swelling or fever, you should see a doctor promptly.

Your orthopedic examination in Hamburg

In our practice at Dorotheenstrasse 48, 22301 Hamburg (Winterhude), we clarify flat foot complaints in a structured manner and plan the next steps together with you. The focus is on conservative, everyday solutions.