Download Pes Planus (Flat Feet)

Page 1 of 7
View this article online at: patient.info/doctor/pes-planus-flat-feet
Pes Planus (Flat Feet)
Pes planus is the loss of the medial longitudinal arch of the foot. It can be flexible or rigid and it results in relative
flattening of the plantar surface. The condition may be lifelong, or acquired through time, inflammation or other
musculoskeletal problems. Treatment is generally only needed if the condition is new, painful or progressing, or
when there is a fixed deformity or other associated problem.
Pes planus refers specifically to loss of the arch in the bony structure of the foot. People with hypertrophied
plantar foot muscles (eg, lifelong barefoot walkers) might appear to have flat feet but if their bony arches are
normal then they do not have pes planus. [1]
The arches of the foot
The arches add elasticity and flexibility to the foot by allowing the midfoot to spread and close. They help the foot
to absorb shock and produce strength to push off and to adjust to balance and walk. They also help distribute
weight evenly around the foot, and act as an energy store when running. [2]
Biomechanical analysis suggests that there are advantages and disadvantages to both high-arched and lowarched feet: the strain on the plantar fascia and metatarsals is greater in the high-arched foot, whereas strain on
the calcaneus, navicular and cuboid are greater in the low-arched foot. A happy medium is perhaps ideal. [3]
Epidemiology [4, 5]
Pes planus may occur in up to 20% of adults, many of whom are flexible and have no resulting difficulties.
Pes planus is common in young children, who typically have a minimal longitudinal arch with forefoot pronation
and heel valgus on weight-bearing. This is present to a greater degree in children of African ethnicity. Studies
suggest around 45% of children aged 3-6 years, with around 5.5° of valgus, although the prevalence decreases
with age. The prevalence of pathological pes planus in this group was less than 1%. Higher prevalence was
associated with obesity and with male gender. Most children develop a normal longitudinal arch by the age of 10
years.
Effects of pes planus on foot dynamics [6]
Collapse of the medial longitudinal arch everts the calcaneus in relation to the talus, so that the foot pronates.
Affected patients usually also have:
Valgus position of the heel and forefoot (turned outwards); and
Pronation (rolling inwards) of the midfoot, usually referred to as 'hyperpronation'.
Hyperpronation moves the transmission of force medially as the weight is transferred forwards on to the walking
foot. This can stretch the soft tissues behind the medial malleolus (the posterior tibial tendon and posterior tibial
nerve) which can lead to tendinopathy and nerve entrapment. The collapsed arch can also stretch the spring
ligament and plantar fascia, leading to plantar fasciitis. Compensatory abduction of the forefoot, together with
altered transmission of weight through the foot, can lead to hallux valgus and metatarsalgia.
Types of pes planus
Flexible or fixed.
Developmental, congenital or acquired.
Page 2 of 7
Aetiology of pes planus [4, 6]
Pes planus in children [7]
Pes planus can be part of normal development:
There may be ligamentous laxity, which is probably determined genetically.
Infants typically have a minimal arch. In neonates and toddlers there is a fat pad under the
medial longitudinal arch which protects it whilst the arch develops and which resolves
between the ages of 2 and 5 years. Children are almost all flat-footed when they first start to
walk - intrinsic laxity and a lack of neuromuscular control compound this.
45% of children aged 3-6 years have flattening of the long arch, with forefoot pronation and
heel valgus on weight bearing.
Most of these children spontaneously develop a strong normal arch by around the age of 10
years.
Obesity in children is significantly correlated with the tendency of the longitudinal arch to
collapse in early childhood. [8]
Abnormal development of the foot, producing pes planus, may be due to:
Neurological problems - eg, cerebral palsy, polio.
Bony abnormalities - eg, tarsal coalition (fusion of tarsal bones), accessory navicular bone
(a small bone which sits in the posterior tibial tendon, weakening support to the arch).
Ligamentous laxity - eg, Ehlers-Danlos syndrome, Marfan's syndrome
A small proportion of flexible pes planus does not correct with growth (physiological pes
planus). These can become rigid if the pes planus leads to bony changes.
Physiological pes planus in adults
Around 20% of adults have pes planus, most of whom lack physiological arch development, probably due to
ligamentous laxity. The majority have a flexible foot and no symptoms. However, if there is also heel cord
contracture, there may be symptoms (see 'Contributing factors', below). [4]
Acquired pes planus in adults [1, 7, 9, 10]
This may be due to reduced arch strength, increased load, or a combination of the two.
Factors which reduce arch strength
Dysfunction of the tibialis posterior tendon - a common and important cause, which develops due to
age-related degeneration, inflammation, hypertension, diabetes, obesity, chronic injuries and,
occasionally, traumatic rupture. The tibialis posterior tendon is the primary dynamic stabiliser of the
foot. Its contraction causes plantar flexion and inversion, elevation of the foot arch and locking of the
midtarsal joints. This allows efficient working of the gastrocnemius during walking.
Tear of the spring ligament (rare).
Tibialis anterior rupture (rare).
A neuropathic foot - eg, from diabetes, polio, or other neuropathies.
Age-related degenerative changes in foot and ankle joints:
Inflammatory arthropathy - eg, rheumatoid arthritis.
Osteoarthritis.
Fractures.
Bony abnormalities - eg, tarsal coalition.
Other bony abnormalities - eg, rotational deformities, tibial abnormalities, coalition (fusion) of tarsal
bones, equinus deformity.
Ligamentous laxity - eg, familial, Marfan's syndrome, Ehlers-Danlos syndrome, Down's syndrome.
Factors which increase load
Footwear: shoes which limit toe movement; high heels (barefoot walking may be protective.) Greater
foot pronation occurs when wearing shoes than when walking barefoot. Shoes elevate the calcaneus,
shorten the Achilles tendon and effectively splint the foot, thereby limiting muscle contraction during
ambulation. Extensive observational data suggest that wearing shoes in childhood is detrimental to the
development of a normal longitudinal arch and that shoeless populations have less chronic foot pain.
Page 3 of 7
A tight Achilles tendon or calf muscles (heel cord contracture): these may help to cause pes planus, or
may contribute to symptoms such as foot pain when there is existing pes planus.
Obesity: obese individuals have an altered gait with more extensive rearfoot eversion. Heavier body
weight results in higher plantar pressures, with the largest effect under the longitudinal arch and
metatarsal heads.
Pregnancy: there is evidence that the endocrine changes of pregnancy (which increase ligamentous
laxity) may predispose to collapse of the foot arches in women who are also obese. [11]
Other factors causing foot pronation - eg, hip abductor weakness and genu valgum.
Presentation and assessment
History
Patients typically present with noticeable pes planus, parental concern, or foot pain.
In children
Age-appropriate history of concerns and motor development.
History of the pes planus including any changes.
Developmental history, particularly motor development (floppiness as a baby, age at first walking,
walking development, stumbling, regression, in-toeing).
Symptoms: walking/running ability and any foot pain.
Older children: level of physical activity, sports participation or avoidance.
Musculoskeletal history - exercise-related pain suggestive of benign joint hypermobility syndrome
Past medical history: other diseases.
Family history of flat feet or of conditions associated with soft tissue abnormalities.
In adults
Establish whether the pes planus is new and whether it is symmetrical.
Ask whether there is foot pain.
Note whether there is alteration of gait.
Ask whether there any other lower limb symptoms or recent history - eg, knee pain, Achilles tendonitis,
plantar fasciitis.
Past medical history: consider injuries, other related disease (neurological, rheumatological,
musculoskeletal).
Note occupation and physical activity.
If pes planus is new, asymmetrical or painful, ask about symptoms of tibialis posterior dysfunction,
which are:
Pain or swelling behind the medial malleolus and along the instep.
Change in foot shape.
Decreasing walking ability and balance.
Ache on walking long distances.
Examination [6]
Observe the pes planus:
With the patient standing, look at the feet from above and behind and all sides, note when
non-weight-bearing, when weight-bearing and when walking. Loss of the arch is visible in
pes planus, with the medial side of the foot close to the ground. Look at the feet from behind
- with pes planus the heel moves outwards (valgus) and the toes may also be pointed
outwards.
Assessment of the foot:
Establish whether the foot is flexible:
Ask the patient to stand on tiptoe. With flexible pes planus, this will reveal the
arch, and the heel will move inwards (varus position).
Evaluate ankle dorsiflexion and plantarflexion and rearfoot, midfoot and forefoot
ranges of motion.
Assess the Achilles tendon - less than 10° of dorsiflexion suggests Achilles
tendon contracture.
Look at the shoes: flexible flat feet may cause rapid and uneven shoe wear.
Page 4 of 7
Look for signs of tibialis posterior dysfunction: [12]
Ask the patient to do 10 unsupported heel raises (stand on one foot on tiptoe, unsupported).
Patients with tibialis posterior dysfunction will be unable to do this.
Further assessment of tibialis posterior dysfunction is detailed in the reference below. [12]
Assess related problems, if relevant - eg, neuropathy or arthritis.
General examination of the musculoskeletal system. Look for evidence of generalised joint laxity, using
the Beighton Score. [13]
Observe gait.
Investigations [4, 12, 14]
The paediatric flat foot proforma is an instrument for assessing for pes planus in mid-childhood, although as yet
there is no clear and evidence-based treatment algorithm. [15] However, overall there is no standardised evaluative
framework and the condition is confused by multiple classifications, most of which look at the arch, feet position
and foot flexibility. Usual assessment methods are X-rays, footprints and visual observations.
In some cases, standing foot X-rays may be useful to show the degree of deformity:
Standing lateral view shows the longitudinal arch and talo-navicular joint.
Standing AP view shows the degree of heel valgus (talo-calcaneal angle).
Management [14, 16]
Treatment in children
The treatment of paediatric flexible pes planus is controversial; there is clear consensus that the condition
reduces with ages and that most children are asymptomatic. Few paediatric flat feet are symptomatic but they
are often unnecessarily treated.
Where foot orthoses are indicated, generic appliances are usually sufficient. Customised orthoses should be
reserved for:
Children with foot pain and arthritis.
Unusual morphology.
Unresponsive cases.
Surgery is rarely indicated for children unless the pes planus is rigid. There is a need for a standardised
assessment, classification and management approach.
Treatment in adults
In many cases, pes planus does not require treatment. Most flexible flat feet are asymptomatic.
The arch may develop spontaneously in children aged under 10 years with flexible pes planus and no
other relevant condition.
In adults, pes planus which has been present a long time, is flexible, bilateral, painless, and is not
progressing, does not require treatment.
Symptomatic and inflexible pes planus may require treatment. Initial options include activity modification, footwear
and orthoses, exercises and medication (non-steroidal anti-inflammatory drugs (NSAIDs)). Comorbidities should
be identified and managed. When treatment is required and non-surgical treatment options have failed then
surgery is considered. Consider referral or treatment if:
Pes planus is fixed, new, asymmetrical or progressing.
Where there is foot pain.
If the patient has another disease which may be contributing (eg, neuropathy, inflammatory arthritis).
There is tibialis posterior dysfunction. This should be treated in its own right: treatment may involve
rest, NSAIDs, orthotics or surgery. [12]
Page 5 of 7
Non-surgical treatment [4, 6]
Exercise for flat feet - both barefoot walking and prescribed activities have been used.
Heel cord stretching, to stretch and lengthen the Achilles tendon and posterior calf muscles, as a tight
Achilles tendon tends to pronate the foot. The patient should be instructed as follows:
Stand facing a wall with hands on the wall at about eye level. Put the leg you want to stretch
about a step behind your other leg.
Keeping the back heel on the floor, bend the front knee until you feel a stretch in the back
leg.
Hold the stretch for 15-30 seconds. Repeat 2-4 times. Do this exercise 3-4 times a day.
Orthotics (inserts or insoles, often custom-made):
These usually contain a heel wedge to correct calcaneovalgus deformity, and an arch
support. In patients with fixed pes planus or arthropathy, customised insoles may help
relieve symptoms.
No high-level evidence supports the use of foot orthoses for flexible pes planus in adults,
although low-level evidence suggests that foot orthoses improve pain and reduce rearfoot
eversion, and there is slightly better evidence that they improve foot biomechanics when
walking. Further research is needed. [17]
Arch supports used without correcting heel cord contracture can make symptoms worse.
Reduce contributing factors: [1]
Wear shoes with low heels and wide toes.
Lose weight if appropriate.
Do exercises to strengthen foot muscles - walking barefoot (if appropriate), toe curls
(flexing toes) and heel raises (standing on tiptoe).
Surgery [4, 6, 14]
The goals of surgery are pain reduction/resolution and realignment of the foot.
Common indications for surgery are:
Cerebral palsy with an equinovalgus foot, to prevent progression and breakdown of the midfoot.
Subtalar fusion is effective in ambulatory patients, although there is a high recurrence rate. [18]
Rigid and painful pes planus.
To prevent progression - eg, with a Charcot joint.
Tibialis posterior dysfunction, where non-surgical treatment has been unsuccessful.
Possible surgical procedures include:
Soft tissue reconstructive procedures - eg:
Achilles tendon lengthening.
Reconstruction of the tibialis posterior tendon.
Arthroereisis (a controversial procedure involving insertion of a spacer into the sinus tarsi to reduce
pronation of the subtalar joint).
Reconstructive osteotomies - rearfoot, midfoot or forefoot, depending on alignment - eg, calcaneal
osteotomy, to re-align the hindfoot.
Arthrodesis:
Subtalar arthrodesis.
Triple arthrodesis - usually a salvage for failed surgical treatment.
Complications and prognosis
Physiological pes planus
It is generally accepted that physiological pes planus is unlikely to cause significant foot problems. [4, 6]
Page 6 of 7
However, some authors suggest that excessive foot pronation may contribute to the development of foot pain and
foot problems such as: [1]
Tibialis posterior dysfunction (because hyperpronation stretches this tendon).
Hallux valgus (because more weight is borne by the medial metatarsals when the foot hyperpronates).
Metatarsalgia (for the same reason).
Plantar fasciitis.
Knee pain: one study found that off-the-shelf foot orthoses were beneficial for patello-femoral pain. [19]
Another study suggested that foot deformity may be linked to greater disability from knee
osteoarthritis. [20]
Pes planus may reduce the shock-absorbing features of the foot, potentially contributing to low back
pain, although it may be protective against metatarsal stress fracture. [4]
The role of pes planus in these problems has not been proved.
Symptomatic or rigid pes planus [21]
Depending on the cause, pes planus can deteriorate, with loss of the longitudinal arch leading to collapse of the
midfoot. With deterioration, a flexible foot can become rigid and/or painful. This can cause significant difficulties
with walking and may require surgery.
Situations where deterioration is likely without treatment include:
Neuropathy - eg, with a Charcot joint there may be rapid and progressive loss of the arch. [6]
Tibialis posterior dysfunction.
Cerebral palsy. [4]
Further reading & references
Richie DH Jr; Biomechanics and clinical analysis of the adult acquired flatfoot. Clin Podiatr Med Surg. 2007 Oct;24(4):61744, vii.
Jacobs AM; Soft tissue procedures for the stabilization of medial arch pathology in the management of flexible flatfoot
deformity. Clin Podiatr Med Surg. 2007 Oct;24(4):657-65, vii-viii.
Kadakia AR, Haddad SL; Hindfoot arthrodesis for the adult acquired flat foot. Foot Ankle Clin. 2003 Sep;8(3):569-94, x.
1. Hyperpronation and foot pain; the physician and sportsmedicine 32;8 (August 2004)
2. Ker RF, Bennett MB, Bibby SR, et al; The spring in the arch of the human foot. Nature. 1987 Jan 8-14;325(7000):147-9.
3. Sun PC, Shih SL, Chen YL, et al; Biomechanical analysis of foot with different foot arch heights: a finite element analysis.
Comput Methods Biomech Biomed Engin. 2012;15(6):563-9. doi: 10.1080/10255842.2010.550165. Epub 2011 Jun 21.
4. Pes planus/flat foot; Wheeless' Textbook of Orthopaedics
5. Pfeiffer M, Kotz R, Ledl T, et al; Prevalence of flat foot in preschool-aged children. Pediatrics. 2006 Aug;118(2):634-9.
6. Flat foot; The Foot and Ankle Clinic
7. Mickle KJ, Steele JR, Munro BJ; The feet of overweight and obese young children: are they flat or fat? Obesity (Silver
Spring). 2006 Nov;14(11):1949-53.
8. Jankowicz-Szymanska A, Mikolajczyk E; Effect of excessive body weight on foot arch changes in preschoolers a 2-year
follow-up study. J Am Podiatr Med Assoc. 2015 Jul;105(4):313-9. doi: 10.7547/14-101.1.
9. Napolitano C, Walsh S, Mahoney L, et al; Risk factors that may adversely modify the natural history of the pediatric
pronated foot. Clin Podiatr Med Surg. 2000 Jul;17(3):397-417.
10. Erol K, Karahan AY, Kerimoglu U, et al; An important cause of pes planus: the posterior tibial tendon dysfunction. Clin Pract.
2015 Feb 5;5(1):699. doi: 10.4081/cp.2015.699. eCollection 2015 Jan 28.
11. Dunn J, Dunn C, Habbu R, et al; Effect of pregnancy and obesity on arch of foot. Orthop Surg. 2012 May;4(2):101-4. doi:
10.1111/j.1757-7861.2012.00179.x.
12. Kohls-Gatzoulis J, Angel JC, Singh D, et al; Tibialis posterior dysfunction: a common and treatable cause of adult acquired
flatfoot. BMJ. 2004 Dec 4;329(7478):1328-33.
13. Smits-Engelsman B, Klerks M, KirbyA; Beighton score: a valid measure for generalized hypermobility in children. J Pediatr.
2011 Jan;158(1):119-23, 123.e1-4. doi: 10.1016/j.jpeds.2010.07.021. Epub 2010 Sep 17.
14. Evans AM, Rome K; ACochrane review of the evidence for non-surgical interventions for flexible pediatric flat feet. Eur J
Phys Rehabil Med. 2011 Mar;47(1):69-89.
15. Evans AM, Nicholson H, Zakarias N; The paediatric flat foot proforma (p-FFP): improved and abridged following a
reproducibility study. J Foot Ankle Res. 2009 Aug 19;2:25. doi: 10.1186/1757-1146-2-25.
16. Halabchi F, Mazaheri R, Mirshahi M, Abbasian L. Pediatric Flexible Flatfoot; Clinical Aspects and Algorithmic Approach.
Iranian Journal of Pediatrics. 2013;23(3):247-260.
17. Banwell HA, Mackintosh S, Thewlis D; Foot orthoses for adults with flexible pes planus: a systematic review. J Foot Ankle
Res. 2014 Apr 5;7(1):23. doi: 10.1186/1757-1146-7-23.
18. Kadhim M, Holmes L Jr, Church C, et al; Pes planovalgus deformity surgical correction in ambulatory children with cerebral
palsy. J Child Orthop. 2012 Jul;6(3):217-27. doi: 10.1007/s11832-012-0413-3. Epub 2012 Jun 20.
Page 7 of 7
19. Collins N, Crossley K, Beller E, et al; Foot orthoses and physiotherapy in the treatment of patellofemoral pain syndrome:
randomised clinical trial. BMJ. 2008 Oct 24;337:a1735. doi: 10.1136/bmj.a1735.
20. Guler H, Karazincir S, Turhanoglu AD, et al; Effect of coexisting foot deformity on disability in women with knee
osteoarthritis. J Am Podiatr Med Assoc. 2009 Jan-Feb;99(1):23-7.
21. Rodriguez N, Choung DJ, Dobbs MB; Rigid pediatric pes planovalgus: conservative and surgical treatment options. Clin
Podiatr Med Surg. 2010 Jan;27(1):79-92. doi: 10.1016/j.cpm.2009.08.004.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical
conditions. EMIS has used all reasonable care in compiling the information but makes no warranty as to its
accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions.
For details see our conditions.
Original Author:
Dr Naomi Hartree
Current Version:
Dr Mary Lowth
Peer Reviewer:
Dr John Cox
Document ID:
1585 (v23)
Last Checked:
19/01/2016
Next Review:
17/01/2021
View this article online at: patient.info/doctor/pes-planus-flat-feet
Discuss Pes Planus (Flat Feet) and find more trusted resources at Patient.
© Patient Platform Limited - All rights reserved.