Flat feet (pes planus) means that no arch can be seen on the inner side of the foot when standing; it is common and usually causes no problems [1]. Most children are born with flat feet and the arch usually forms by the age of 10 [1][3]; a painless, flexible flat foot needs no treatment [2][3]. Insoles, special shoes and exercises do not change the shape of the foot, but they can ease pain and stiffness [1][3]; a flat foot that develops in adulthood, is painful or affects only one foot does need to be examined [1][7].
What are flat feet and how can you tell?
Flat feet, also called fallen arches, are feet in which the sole presses flat on the ground [1]. To check, look at the inner side of the foot while standing: if no arch is raised off the ground, the foot is flat [1].
They are common, do not usually cause any problems and should not stop any activity, including sport [1]. If they are not causing problems, in you or in your child, nothing needs to be done [1].
What causes flat feet?
Often there is no obvious cause; it is simply the way the foot is built, and it sometimes runs in families [1][2]. Less common causes are [1][6][7]:
- The bones of the foot not growing properly in the womb
- Stretching of the tissues of the foot through injury, ageing or being overweight
- Conditions such as cerebral palsy and spina bifida
- Two or more bones of the foot being joined together (tarsal coalition)
- In adults, inflammation or a tear of the posterior tibial tendon, which holds up the arch
At what age do children's flat feet show, and do they correct themselves?
Most children are born with flat feet, that is, with very little arch [2][3]. The arch forms with growth; it usually develops between 3 and 10 years of age [1]. In children with flexible flat feet the arch often does not begin to develop before the age of 5; in some it never develops [2].
According to the Pediatric Orthopaedic Society of North America (POSNA), in about 80–90% of children flat feet correct themselves with growth; in 1 or 2 out of every 10 children they continue into adulthood [3]. In young children this improvement does not depend on the type of footwear worn [5]. A flexible flat foot is usually painless and does not interfere with walking or sport; if it continues into adolescence there may be an aching pain in the sole of the foot [2].
What are flexible and rigid flat feet?
In a flexible flat foot the arch disappears on standing and reappears on sitting or rising onto tiptoe [2][3]. It always affects both feet and is regarded as a variation of a normal foot [2].
In a rigid flat foot no arch forms even on tiptoe; this may point to a more serious problem [2][3]. One cause is tarsal coalition: an abnormal connection between bones of the foot can result in a severe, rigid flat foot [6]. Signs usually appear in early adolescence: pain and stiffness in the foot, difficulty walking on uneven ground and repeated ankle sprains [6]. Some flexible flat feet may also become rigid with growth [3].
How are flat feet assessed, and how is the degree measured?
On examination the child is asked to sit, stand and rise onto tiptoe; the tightness of the Achilles tendon and the wear pattern of the shoes are checked [2]. Not everyone needs an X-ray; one is taken if the flat foot is painful or rigid, or if there are signs of a nerve or muscle condition [3].
In adults the doctor checks whether the heel has drifted outwards, whether the person can rise onto tiptoe on one leg and how flexible the foot is [7]. X-rays are preferably taken standing, with weight on the foot; an MRI scan may be requested to look at tendons and ligaments [7].
These sources contain no table of "degrees of flat foot"; the change in shape is described as mild, moderate or severe [7]. Treatment is guided by pain, how severe the deformity is, how flexible the foot is and whether there is arthritis in the joints [2][7].
What do insoles, shoes and exercises do?
With a painless, flexible flat foot a child can wear regular shoes and take part in all activities [3]. POSNA states that there are no exercises, braces, special shoes or insoles that will change the shape of a flexible flat foot [3]; according to the UK National Health Service (NHS), too, these do not change the shape of the feet but can help with pain and stiffness [1].
According to a Cochrane review, in healthy children without pain custom-made or ready-made insoles make little or no difference in pain after one year compared with shoes alone; this finding rests on a single trial and the certainty of the evidence is low or very low [4]. The review concludes that, in the absence of pain, there is no evidence to support expensive custom-made insoles [4]. No study shows that insoles prevent future problems in a child without pain [3]; nor is there strong evidence that long-term use corrects the structure of the foot [5].
If there is pain or the feet tire quickly, a soft insole that supports the arch may ease the symptoms; ready-made insoles can be just as effective as custom-made ones and are much less expensive [2][3]. Hard insoles can make the pain worse [3]. Wide, comfortable shoes with a low heel are advised [1].
Among exercises for flat feet in children, the one the sources recommend is stretching of the Achilles tendon, done when there is pain or tiredness [2][3]: stand facing a wall, put one foot forward and bend that knee, keep the back knee straight; hold for 30 seconds and switch legs [3]. If a painkiller is needed, a pharmacist or doctor can advise which one is suitable [1].
Flat foot that develops in adulthood
A foot that gradually flattens in an adult who had an arch is a separate condition; it is called adult acquired flatfoot or posterior tibial tendon dysfunction [7]. This tendon holds up the arch during walking; when it becomes inflamed or torn it can no longer support the arch and the foot flattens [7]. It is more common in women and in people over 40; obesity, diabetes and high blood pressure increase the risk [7].
The pain is on the inner side of the foot and ankle and may be accompanied by swelling; it increases with activity, and as the arch collapses the outer side of the ankle may also hurt and the heel drifts outwards [7].
With appropriate non-surgical treatment the symptoms settle in most patients; pain may last longer than 3 months even when treatment starts early [7]. Activities that worsen the pain are reduced, and exercise that puts little load on the foot, such as cycling and swimming, is chosen [7]. The most commonly used measure is an insole: a ready-made insole may be enough for a mild change in shape, while moderate and severe changes need a custom-made one [7]. An ankle brace, physiotherapy and, if other measures are not enough, a cast or walking boot for 6 to 8 weeks are further options; a cortisone injection into the tendon is not normally given because of the risk of rupture [7].
When is surgery for flat feet considered?
Surgery is rarely needed for flat feet; it may be considered when there is a problem with the bones, tissues or muscles of the foot and other treatments have not worked [1]. In children it is almost never needed for flexible flat feet; it may be recommended for teenagers with persistent pain or whose flat foot becomes rigid over time [2]. In tarsal coalition, surgery is considered when rest, insoles and a temporary cast have not helped [6].
In flat foot that develops in adulthood, surgery is considered if the pain has not improved after several months of appropriate treatment [7]. In a flexible foot a tendon transfer and cutting and shifting of bone (osteotomy) are used; in a stiff or arthritic foot, joint fusion (arthrodesis) [7]. Recovery takes 6 months or more; the most common complaint is that the pain is not completely relieved [7].
When not to wait
Flat feet are usually harmless; however, see a doctor without waiting in the following situations [1][3][7]:
- The feet are painful, stiff, weak or numb
- Only one foot is flat
- Your foot has flattened although you had an arch
- You often injure your foot or ankle
- There are problems with walking or balance
- In a child, no arch forms even on tiptoe
- The inner side of the ankle is painful and swollen, or you cannot rise onto tiptoe on one leg
Frequently asked questions
- When do flat feet in children go away?
- The arch usually develops between 3 and 10 years of age [1]; in about 80–90% of children flat feet correct themselves with growth [3]. In some children the arch never develops; if it causes no problems, nothing needs to be done [1][2].
- Are insoles or orthopaedic shoes necessary for flat feet?
- Not if there is no pain: special shoes and insoles do not change the shape of the foot, and there is no evidence to support custom-made insoles in a child without pain [3][4]. If there is pain, a soft ready-made insole may ease the symptoms [2][3].
- Can exercises cure flat feet?
- Exercises do not change the shape of the foot [1][3]. Stretching exercises, however, can help to reduce symptoms such as pain and stiffness [1][2].
- Which doctor should a child with flat feet see?
- The child can first be assessed by a paediatrician, who refers to an orthopaedic doctor if there are concerns [3]. If there is pain, stiffness or a flat foot on one side only, a doctor should be seen [1][3].
- Are flat feet a bar to military service?
- Fitness for military service is decided not by this article or this clinic but by the military health regulations and the authorised medical boards that work under them.
This article is a general summary; diagnosis and treatment decisions are made by the doctor who examines you.
Sources
- Flat feet. NHS (nhs.uk), 2025. nhs.uk
- Flexible Flatfoot in Children. American Academy of Orthopaedic Surgeons (OrthoInfo), n.d.. orthoinfo.org
- Flexible Flat Feet. Pediatric Orthopaedic Society of North America (POSNA OrthoKids), n.d.. orthokids.org
- Foot orthoses for treating paediatric flat feet. Cochrane Database of Systematic Reviews (Evans AM, et al.), 2022. pubmed.ncbi.nlm.nih.gov
- The long-term structural effect of orthoses for pediatric flexible flat foot: A systematic review. Foot and Ankle Surgery (Choi JY, et al.), 2019. pubmed.ncbi.nlm.nih.gov
- Tarsal Coalition. American Academy of Orthopaedic Surgeons (OrthoInfo), n.d.. orthoinfo.org
- Progressive Collapsing Foot Deformity (Flatfoot). American Academy of Orthopaedic Surgeons (OrthoInfo), n.d.. orthoinfo.org
This article is general information and does not replace an examination or imaging. If you have symptoms, see a doctor.
More in this area
- Achilles tendon rupture: surgery or a boot?
- Ankle sprain: when is an X-ray needed?
- Bunion (hallux valgus): when is surgery needed?
- Foot pain: what causes it, what helps and which specialist to see?
- Broken foot and broken toe: symptoms and how long healing takes
- Ingrown toenail: what causes it, how does it heal, and when is a procedure needed?
- Heel spurs and plantar fasciitis: what causes heel pain and how does it settle?