Pain guide · Hip pain

Perthes disease: when the ball of a child's hip loses its blood supply, and how it regrows

In Perthes disease, the blood supply to the ball at the top of the thigh bone is interrupted for a while. The bone softens and can flatten, then new bone grows back over 2 to 5 years. It mostly affects children aged 4 to 10, more often boys, and usually starts with a limp, sometimes painless, or pain in the groin, thigh or knee. Nobody knows the cause, and it isn't caused by an injury or by sport. Most children are treated without an operation and younger children usually do better, but nobody yet knows which treatment works best, and the evidence for physiotherapy is thin.

A children's orthopaedic team manages it, with X-rays until the hip has healed, and their limits on walking, sport and any cast or surgery come first. This guide is for parents: the warning signs, what the X-rays mean, which activities to pause and which to keep, gentle daily hip exercises with 3D demos, school and wellbeing, and what long-term studies say about the hip in adult life.

3-stage exercise plan When to get help 41 sourcesUpdated 21 October 2026

When to get help first

Exercise is for pain that has been checked or is clearly mild and settling.

Get urgent medical help if

Ask for an urgent GP appointment or get help from NHS 111 the same day if your child gets sudden pain in their hip, thigh or knee, or is limping or can't put any weight on 1 leg. Hip problems can sometimes be felt in the thigh or knee.
Go to A&E if your child can't put any weight at all on the leg, even after children's painkillers, or the pain is severe or getting worse quickly.
If your child is already being treated for Perthes disease and suddenly has much worse pain, a new or much worse limp, or won't put weight on the leg: contact their orthopaedic team the same day, or NHS 111 out of hours.
Ask for an urgent GP appointment or get help from NHS 111 for severe pain in 1 joint that started suddenly, swelling around a joint, skin over a joint that has changed colour, or difficulty moving a joint, especially with a high temperature or feeling hot, cold or shivery: it could be a joint infection.
Call 999 or go to A&E if your child seems seriously unwell and you think it could be sepsis: they're breathing very fast or having difficulty breathing; have blue, grey, pale or blotchy skin, lips or tongue; have a rash that does not fade when you press it; are confused, not responding like they normally do, difficult to wake or more sleepy than usual; feel very hot or cold to the touch or are shivery; or, if they're under 5, haven't had a pee for 12 hours.
After an operation on the hip: a wound that is red, swollen, smelly or leaking, a high temperature or feeling hot, cold or shivery, or pain that is getting worse. Contact the surgical team the same day, or NHS 111 out of hours.
In a cast, boot or splint: pain that is getting worse, toes that are numb, tingling, swollen, blue or white, a cast that feels too tight, or a bad smell from under it. Contact the team the same day, or NHS 111 out of hours.
Same day (GP or NHS 111): throbbing pain and swelling in one leg, usually the calf or thigh, with red, blue or darker skin or swollen veins. It could be a blood clot (deep vein thrombosis, DVT), which is more likely while you're moving about much less than usual or after a hospital stay.
Pain and swelling in your hip or leg with breathlessness or chest pain: call 999 or go to A&E, and do not drive yourself. It can be a blood clot that has reached the lungs.

See a doctor or physiotherapist if

With Perthes disease: pain, a limp or stiffness that is getting worse, pain at night, or your child using the leg less. Contact the orthopaedic team or physiotherapist rather than waiting for the next X-ray.
Your child seems low, anxious or withdrawn, or is struggling at school or with friends during treatment: tell the team. Activity limits can affect mood, and support is available.
See a GP if your child has a rash, swelling or unusual bruising on the legs, leg pain and a high temperature, is unusually tired or sleepy a lot of the time, or doesn't want to eat or is losing weight.
See a GP for bone pain or tenderness, particularly if it's worse at night, or a lump or swelling that is growing.

Understand it

What it is

The top of the thigh bone is a ball (the femoral head) that sits in the hip socket. In Perthes disease, also called Legg-Calvé-Perthes disease, the blood supply to the ball is interrupted, part of the bone dies and softens, and it can flatten. Over several months new blood vessels grow back, and new bone is laid down and reshaped over 2 to 5 years, much as bone heals after a break, only slower.

Specialists describe four stages: an initial stage, fragmentation (when the soft bone is most likely to flatten), regrowth and healed. The aim of every treatment is for the ball to heal as round as possible and stay well seated in the socket.

Nobody knows what interrupts the blood supply. It isn't caused by an injury or a general illness, and the Association of Paediatric Chartered Physiotherapists says there is no known link with physical activity. A review describes links with social deprivation and with parents who smoke.

Sources 1, 2, 3, 4, 5

Who gets itStrong evidence

In a UK national study, 371 children were newly diagnosed in 18 months: 2.48 in every 100,000 children aged 0 to 14 each year. Boys were affected about 3 times as often as girls (3.68 against 1.22 per 100,000), the middle (median) age was 5.4, and rates were highest in northern England. In the same study, 5.8% had a parent, brother or sister who had had it.

Usually one hip is affected. In the UK study, 6.7% had both hips affected when diagnosed, and 2.1% of the rest developed it in the other hip within 2 years. Some leaflets give higher figures for both hips, about 10% or 1 in 7; the national study is the more reliable count.

Sources 6, 4, 1, 7

How it shows

Symptoms usually come on gradually and can come and go: a limp, often painless at first, that can get worse over a few weeks, or an odd running style in sport; pain in the hip or groin that can spread to the thigh or knee (in some children, knee pain is the first or only symptom); a stiff hip, with moving the leg out to the side and turning it inwards limited first; and later, a thinner thigh and a slightly shorter leg.

A 2025 UK review written for GPs says it commonly starts as a painless limp, in children aged 2 to 14, and that spotting it early matters. A Hull leaflet notes that children may have had problems for 6 months or more before diagnosis, because the earliest stage doesn't show on an X-ray. That's why a limp, or hip, thigh or knee pain, needs the same-day check in the warning signs above.

Sources 1, 2, 3, 5, 8, 9

What the X-rays do and don't meanEmerging evidence

A specialist confirms it on X-rays of both hips, usually including one with the legs in a frog position. Early on, the X-ray can be normal and may be repeated after a few months, and a bone scan or magnetic resonance imaging (MRI) scan can show it sooner.

X-rays then follow the ball as it softens, breaks up and slowly re-forms. A US orthopaedic society warns parents that X-rays often look worse before they get better: a crumbly-looking ball in the fragmentation stage is part of the normal course, not a sign that treatment has failed. Specialists use several X-ray grading systems to judge severity and the final shape; you don't need to learn them.

Sources 2, 3, 6

How it usually goesEmerging evidence

From the first symptoms to a healed hip usually takes 2 to 5 years (3 to 4 in one leaflet), with X-rays along the way. A US orthopaedic society says most children are back to everyday activities without major limits after 18 to 24 months of treatment.

At 2 years in the UK study, about 4 in 10 hips (44%) were round or nearly round, about 4 in 10 (38%) were in between, and 18% were flattened, though hips can keep reshaping after that.

Sources 1, 8, 3, 6

How it affects children and familiesEmerging evidence

In the UK study, quality-of-life scores were markedly low at diagnosis. Physical function was the most affected and improved the most, but even at 2 years the scores were low enough to count as an ongoing major long-term condition.

Parents in a UK interview study described effects on pain, sleep, play, school and family life, and children reported limits even on good days. A 2026 review of 21 studies linked Perthes disease with more attention and behaviour difficulties early on, more pain and lower function, and more low mood, with worse quality of life in girls, older children and flatter hips.

Sources 6, 10, 11

What helps, and how strong the evidence is

Younger children usually do better; studies put the age where it starts to matter at 6 to 8Strong evidence

In a US multicentre study of 345 hips in children aged 6 to 12 at onset, treatment made no difference in children aged 8 or under, and hips with the most severe X-ray grade did poorly whatever was done. In a Norwegian study of 368 children, treatment made no difference under 6, and having more than half of the ball affected was the strongest predictor of the outcome. In the UK study, onset over 6 and being a girl each predicted a worse hip shape at 2 years.

So the direction is clear: younger children usually do better. The exact age where it starts to matter differs between studies, at 6 to 8, and an NHS leaflet gives 6 or younger as the best outlook and 8 or older as a sign of a poorer one.

Sources 12, 13, 6, 2

Surgery or not: the specialist's decision, with real uncertaintyMixed evidence

In the UK study, two-thirds of hips were treated without surgery over 2 years, most by watching and waiting alone, and about a third had an operation. Surgeons' decisions turned mainly on stiffness and an age over 8, and surgery made no detectable difference to the hip's shape at 2 years.

Other studies point the other way for some children: in the US study, children over 8 with a middle X-ray grade did better with surgery, and in Norway, children over 6 with more than half of the ball affected did better with an operation on the thigh bone (an osteotomy). Because of this uncertainty, a UK national trial, Op NON-STOP, is randomly allocating children aged 5 to 12 to surgery or the best non-surgical care.

Sources 6, 12, 13, 14, 15

Physiotherapy keeps the hip moving; there's no good evidence it changes the final shapeEmerging evidence

A 2020 review found 15 studies comparing non-surgical treatments in 1,745 children, none of them randomised trials, and said no recommendation could be made for any of them. In the one controlled physiotherapy study, 8 children who did stretching, strengthening and balance work gained hip movement and strength, while 9 who were only observed lost movement, but the X-rays didn't change. In the US multicentre study, hips treated with range-of-movement exercises ended up no different from those with no treatment or a brace.

Physiotherapy is still standard, and sensible: it was recommended for 61% of children in the UK study, and in a UK case review, 26 of 32 children were referred and seen a median of about 10 times in 2 years. In an international survey of 160 surgeons, 71% rated keeping the hip moving as very important, most supported stretching in the early stages, and they disagreed about strengthening then. Surgeons and physiotherapists in Sweden agreed on stretching at every stage and disagreed on strengthening in the first two. So the exercises in this guide are for movement, strength and comfort, not to reshape the ball.

Sources 16, 17, 12, 6, 18, 19, 20

Activity: high impact paused in the early stages, swimming and cycling keptEmerging evidence

Surgeons in the international survey strongly agreed on discouraging high-impact activity, such as trampolining, gymnastics and ball sports, including school sport, in the early stages, easing these limits somewhat as the hip heals, and they allowed or recommended swimming and cycling in almost every case. Many used pain, as well as the stage, to guide activity, and there was no agreement on when full activity can return.

UK leaflets say the same: avoid running, jumping (including trampolines) and contact sport; swimming is a good activity because the hip moves through its full range without the pull of gravity; cycling, with supervision; and in PE, balance, ball skills and climbing without jumping off the apparatus. Australian state health advice is the same. None of this has been tested in a trial.

Sources 19, 20, 2, 21, 22, 23

Walking and weight-bearing: the team decides, and restrictions have costsMixed evidence

UK and Scandinavian surgeons mostly let children walk as comfort allows, while surgeons in Eastern Europe recommended no weight on the leg; none of the Swedish surgeons or physiotherapists surveyed recommended keeping all weight off it. In a US study, at least 6 months with little or no weight on the leg, started at the earliest stage, went with less flattening (good X-ray results in 50% against 0% with treatment of the symptoms only), and a review cites another study favouring longer weight relief.

Restrictions have costs too. In 100 US children aged 8 to 14, restrictions went with worse mobility scores, and in 92 children aged 5 to 7, moderate restrictions went with more anxiety and low mood. They didn't lead to extra weight gain in 130 children. These are observational studies of selected children, so this is a decision for your child's team, and if your child is restricted, ask about support for mood, play and school.

Sources 19, 20, 24, 4, 25, 26, 27

Braces and castsEmerging evidence

In the Norwegian study, a brace that held the legs apart did no better than physiotherapy, and the authors advised giving it up. The 2020 review found similar rates of poor outcomes with braces and with no treatment. Casts that hold the legs apart are still used in some countries, usually by specialist decision.

Sources 13, 16, 3

Hip replacement in adult life: two long-term cohortsMixed evidence

In Denmark, 13% of 167 patients treated in childhood with a splint had had a hip replacement at a mean of 47 years later, against none of a matched group without Perthes disease. In Norway, 19% of 244 hips treated without surgery had been replaced at a mean of 48 years, at an average age of 46.

Other figures vary with the era, treatment and length of follow-up: 6.8% after non-surgical treatment across 27 long-term studies, rising to 23% in studies that followed people for over 40 years, and 22% in a web survey of 1,182 adults, who chose to take part and may include more people with problems. In a small Dutch group with moderate disease, over half showed signs of arthritis on X-ray at a median of 41 years. So many adults who had Perthes have good hips for decades, and some need a replacement in middle age.

Some leaflets give much gloomier figures: one NHS leaflet estimates that about half will need a hip replacement by 50 to 60, and an older Australian fact sheet that a third have arthritis needing treatment by 30. The long-term studies above don't support numbers that high, so if you've read them, ask the team what they expect for your child.

Sources 28, 29, 30, 31, 32, 2, 33

Hip shape and the risk later: one cohortEmerging evidence

In the Norwegian cohort, 3% of hips that healed round needed a replacement, against 25% of oval ones and 46% of those that healed flat. Onset at 6 or older went with more replacements (28% against 10%).

That is one cohort's finding: the meta-analysis of 27 studies didn't find a direct link between the X-ray shape grade and hip replacement, though it did find more replacements with older age at onset.

Sources 29, 30

How much pain is OK while you exercise?

The specialist's limits first; then gentle movement, never forced, and no new limp the next day (editorial)Emerging evidence

The specialist's limits on walking, crutches, impact and any cast or brace come first, before any pain rule.

Stretches and movement exercises: gentle, never forced. Two NHS physiotherapy leaflets say no exercise should be forced or bring on pain, that some aching during or after can be normal, and to stop exercises that make the symptoms worse or bring on new pain.

Everyday activity: if an activity leaves your child limping more, or with hip, thigh or knee pain that lasts into the evening or the next morning, cut it back, and tell the team if it keeps happening. This is our suggestion (editorial), not a tested rule; surgeons in an international survey often used pain, alongside the stage, to guide activity.

Sudden worse pain, not putting weight on the leg, a fever, or a hot, swollen joint aren't covered by this rule: see the warning signs.

Sources 34, 7, 19

The exercise plan: 3 stages

Start at the first stage. Each move opens a full guide with a 3D demo.

Stage 1

Keep the hip moving (from diagnosis, as the team allows)

About 10 minutes a day of gentle movement, especially moving the leg out to the side and turning it in and out, which Perthes disease stiffens first (the time is editorial). Walk as the team advises. Swimming and cycling as the team allows; no running, jumping, trampolines or contact sport for now. Do it with your child and make it a game.

Reclining bound angle pose (Supta Baddha Konasana) demonstrated on the 3D figure

3D demoReclining bound angle pose (Supta Baddha Konasana)Beginner · Firm cushion

Hold 30 s, 4 times · Plymouth's NHS leaflet dose. Rest your hands on the knees to guide them, but never push; cushions under the thighs if it pulls

Harder: Wide-angle seated forward fold (Upavistha Konasana)

Single knee-to-chest stretch demonstrated on the 3D figure

3D demoSingle knee-to-chest stretchBeginner · No equipment

Hold 30 s, 4 times each leg · Plymouth's NHS leaflet dose. Ease off for a pinch at the front of the hip

Harder: 90/90 hip lift-off

Hip windshield wipers demonstrated on the 3D figure

3D demoHip windshield wipersBeginner · No equipment

10 slow passes side to side, 2 rounds · The move page's dose. It turns each hip in and out; make it smaller if it pinches in the groin

Easier: Supine heel slide · Harder: 90/90 switch

Glute bridge demonstrated on the 3D figure

3D demoGlute bridgeBeginner · No equipment

Hold 5 to 10 s, 10 times · Plymouth's NHS leaflet dose

Easier: Pelvic tilt into bridge · Harder: Single-leg glute bridge

Stationary cycling demonstrated on the 3D figure

3D demoStationary cyclingBeginner · Cardio machine

10 to 20 min, easy, or a bike ride outside · As the team allows. Editorial time

Easier: Recumbent exercise bike · Harder: Air bike intervals

Move on when: The team is happy with the hip's movement, and pain has settled enough to add strength work. Keep stage 1 going daily throughout.

Follow along: a timer, a cue and the next move, one step at a time.

Stage 2

Build strength around the hip (as pain and the team allow)

Strength for the buttock and side-hip muscles, which weaken when the leg is used less, 3 times a week alongside stage 1 (editorial). Surgeons disagree about strength work in the earliest stages, so follow the physiotherapist on when to start.

Side-lying leg raise demonstrated on the 3D figure

3D demoSide-lying leg raiseBeginner · No equipment

2 sets of 8 to 10 each side · Editorial. Heel leading, leg slightly behind the body

Easier: Lateral band walk · Harder: Lateral band walk, band at the feet

3D demoClamshellBeginner · No equipment

2 sets of 10 each side · Editorial. Keep the pelvis still

Easier: Supine isometric hip abduction (belt press) · Harder: Lateral band walk

Staggered-stance bridge (offset bridge) demonstrated on the 3D figure

3D demoStaggered-stance bridge (offset bridge)Beginner · No equipment

5 slow lifts each side once a day, building to 2 sets of 5 to 10 · The move page's dose, from an adult hip trial's programme

Easier: Pelvic tilt into bridge · Harder: Single-leg glute bridge

Single-leg stand demonstrated on the 3D figure

3D demoSingle-leg standBeginner · A wall

3 holds of 10 to 20 s on each leg, near a support · Editorial; balance work suits PE, one NHS leaflet says

Easier: Tandem stance and heel-to-toe walk · Harder: Single-leg reach matrix

Sit to stand from a chair demonstrated on the 3D figure

3D demoSit to stand from a chairBeginner · A bench or box

2 sets of 8 to 10 · Editorial. A chair high enough to be comfortable

Easier: Sit to stand, pushing on the thighs · Harder: Bodyweight squat

Move on when: The specialist says the hip is in the later stages of healing on X-ray and lifts the limit on impact. Until then, stay in stages 1 and 2; that may be a year or more.

Follow along: a timer, a cue and the next move, one step at a time.

Stage 3

Back to running, jumping and sport (only when the specialist lifts the impact limit)

A gradual return to normal sport as the hip heals: build impact over weeks, and keep the strength work going twice a week (editorial).

3D demoStep-upBeginner · A step

2 to 3 sets of 8 on each leg, holding a rail at first · Editorial

Easier: Low step-up · Harder: Dumbbell step-up

Lateral band walk demonstrated on the 3D figure

3D demoLateral band walkBeginner · A band

2 sets of 10 steps each way · Editorial

Easier: Hip abduction machine · Harder: Lateral band walk, band at the feet

Single-leg glute bridge demonstrated on the 3D figure

3D demoSingle-leg glute bridgeIntermediate · No equipment

2 sets of 6 to 8 each side · Editorial

Easier: Glute bridge · Harder: Barbell hip thrust

Ankle bounces (mini pogo) demonstrated on the 3D figure

3D demoAnkle bounces (mini pogo)Beginner · No equipment

2 sets of 15 to 20 small, quiet bounces · Editorial. Only once the specialist has cleared impact

Harder: Pogo hops

Treadmill jogging demonstrated on the 3D figure

3D demoTreadmill joggingIntermediate · Cardio machine

Walk-jog intervals every other day, building time before speed · Editorial; outdoors is fine

Easier: Treadmill walking · Harder: Sprint intervals

Move on when: Full activity stays comfortable, with no new limp the next day. Keep the strength and movement work going; the team keeps checking the hip until it has healed.

Follow along: a timer, a cue and the next move, one step at a time.

What to change for now

Two exercises the figure can't show

An NHS physiotherapy leaflet and a US orthopaedic society describe these two. Keep them gentle.

1. The squashed frog: lying on the tummy, bend the knees out to the sides with the soles of the feet together, and feel the stretch on the inside of the legs. Hold 30 seconds, 4 times (the Plymouth leaflet's dose).
2. Leg rolls: your child lies on their back with the legs straight, and you gently roll the whole leg inwards and outwards, 10 times (a US orthopaedic society describes the exercise; the count is editorial). Stop if it hurts.
3. Never force either one. If your child's physiotherapist has given you a programme, follow theirs.

Sources 7, 3

Swimming and water exercise

Swimming is the activity UK leaflets recommend most, because the water takes the weight off the hip while it moves through its whole range. Some services offer hydrotherapy (exercise in a warm pool) as well as the home programme. Some surgeons limit swimming in the early stages, for example to slow swimming with no racing and no jumping from the board, so check with the team.

Sources 2, 21, 22, 19

School and play

Leaflets suggest a letter to school about any limits, and talking to the PE teacher: no running or jumping, but balance, ball skills and climbing without jumping off the apparatus are fine, or your child can do their physiotherapy programme instead. Crutches at break time can help if the team suggests them.

Sitting cross-legged for long spells can be painful, so a chair helps. Long walks can hurt, so a wheelchair can help for long trips, though it isn't usually needed around school. School trips shouldn't be missed if your child can get about with crutches or a wheelchair.

Sources 21, 22, 8

After surgery (as your team allows)

After an operation such as an osteotomy, children usually spend several weeks in a cast, or about 6 weeks without putting weight on the leg, using crutches or a frame, then have physiotherapy to bring back movement and strength. X-rays continue until the hip has healed. The team's plan replaces stages 1 and 2 until they say otherwise.

Sources 3, 8

Looking after your child's wellbeing

Perthes disease affects play, sleep, school and friendships as well as the hip, and moderate activity limits went with more anxiety and low mood in young children. A 2025 UK review says support with mood and school belongs in early care. Tell the team if your child is struggling. Steps, a UK charity, supports families of children with Perthes disease.

Sources 26, 10, 9, 35

Positions to swap, and why

Habit or position	Why it matters	Instead
Ankle bounces, hopping, trampolines and bouncy castles in the early stages	Most surgeons and UK leaflets advise avoiding high impact while the ball is soft.	Swimming and cycling, as the team allows.Try: Stationary cycling
Contact sport and running games in PE in the early stages	Surgeons discourage high-impact sport, including school sport, in the early stages.	Balance, ball skills and climbing without jumping off the apparatus, or the home exercise programme.
Pushing the knees down in the butterfly stretch	NHS leaflets say no exercise should be forced or bring on pain.	The lying version, with cushions under the thighs, held gently.Try: Reclining bound angle pose (Supta Baddha Konasana)
Deep end-of-range hip stretches such as the frog rock	They push the hip to the end of its range, beyond the gentle movement NHS leaflets describe (our reasoning).	The stage 1 moves.Try: Hip windshield wipers
Sitting cross-legged for long spells	An NHS leaflet says it can be painful.	A chair at school and at home.
Long walks on painful days	Walking long distances can cause pain.	A wheelchair or buggy for long trips.
Keeping your child off their feet without the team asking	UK practice mostly allows walking as comfort allows, and restrictions went with worse mobility and, in 5 to 7 year olds, more anxiety and low mood.	Stay active within the team's limits.
Buying braces, special shoes or supplements	Braces did no better than physiotherapy or no treatment, and nothing else has been tested.	Follow the team's plan.

Routines to follow

Low-impact leg workout (no jumping)

A gentle leg strength routine with no jumping: sit-to-stands, step-ups, wall sits, bridges and calf raises.

20 minBeginner7 movesA bench or box, A step

Glute workout at home

A 25-minute glute workout with bodyweight and a mini band: bridges, clamshells, band walks, kickbacks and lunges.

25 minBeginner9 movesA wall, A band

Balance exercises routine

Balance practice in 10 minutes: tandem stance, single-leg stands, marches, heel walks, tree pose and floor transfers.

10 minBeginner7 movesA wall, A bench or box

More moves for this area

Questions people ask

What is Perthes disease?

The blood supply to the ball at the top of the thigh bone is interrupted, the bone softens and may flatten, then new bone grows back over about 2 to 5 years. It mostly affects children aged 4 to 10, and boys more often than girls.

What causes it?

Nobody knows. It isn't caused by an injury, and there's no known link with physical activity. It is more common in areas of deprivation and in children whose parents smoke, which suggests something in the environment plays a part.

What are the first signs?

Usually a limp, often painless at first, and pain in the hip, groin, thigh or knee that comes and goes; in some children knee pain is the first sign. Any limp, or sudden hip, thigh or knee pain, needs an urgent GP appointment or NHS 111 the same day.

How is it diagnosed?

With X-rays of the hips. Early on the X-ray can be normal and may be repeated, or an MRI or bone scan used. X-rays often look worse before they look better, which is part of the normal course.

Will my child need an operation?

Most don't: in a UK national study, two-thirds of hips were treated without surgery. Surgery is mainly considered for older children with more of the ball affected, and a UK trial is now comparing surgery with the best non-surgical care.

Can my child still play and do sport?

Yes, with limits in the early stages: most specialists advise avoiding running, jumping, trampolines and contact sport while the bone is soft, and allow swimming and cycling. Your child's team decides when full sport can return.

Does my child need crutches or a wheelchair?

Most UK teams allow walking as comfort allows. Crutches may help when pain is bad, and a wheelchair for long trips. Some teams restrict weight on the leg for longer, and that is the specialist's decision for your child.

What exercises help?

Gentle daily movement of the hip, especially moving the leg out to the side and turning it in and out, plus bridges and side-hip strength as pain allows. They keep the hip moving and the muscles strong, but there's no good evidence they change the final shape of the ball.

How long does it last?

Usually 2 to 5 years from the first symptoms to a healed hip, with X-rays along the way. Most children are back to everyday activities without major limits after 18 to 24 months of treatment.

Will my child get arthritis later?

Some will, usually decades later. In long-term studies, 13% of Danish patients had had a hip replacement 47 years on, and 19% of Norwegian hips 48 years on. Younger children usually do better.

Can it affect the other hip?

Sometimes. In a UK national study, 6.7% of children had both hips affected when diagnosed, and 2.1% developed it in the other hip within 2 years.

How can we look after our child's wellbeing?

Perthes disease affects play, sleep and school as well as the hip. Tell the team if your child seems low or anxious, especially if activity is restricted. UK charities such as Steps support families.

Related exercise guides

Other pain guides

Sources

Exercise education, not a diagnosis or treatment plan. It is written from the guidelines and studies listed above; review by a clinician is pending. If your pain follows an injury, is severe, is getting worse, or comes with any warning sign listed on this page, get it assessed. Health disclaimer.