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Radiology • Paediatric Musculoskeletal Ultrasound

Infant Hip Ultrasound

Also called: DDH Ultrasound • Baby Hip Scan • Graf Hip Ultrasound

Infant hip ultrasound shows the largely cartilaginous ball-and-socket joint before it is well seen on an X-ray. It assesses whether the femoral head sits securely in the acetabulum and whether the socket is developing with adequate depth and coverage.

The scan is commonly requested after a breech pregnancy, a close family history, an abnormal hip examination or during treatment for developmental dysplasia of the hip. It is painless, uses no radiation and usually examines both hips.

Book a Scan How to prepare ↓

A sick or painful infant needs urgent clinical assessment—not routine DDH screening

Seek Urgent Help for Fever, Hip Swelling or Refusal to Move a Leg

Arrange urgent paediatric assessment if your baby has:

  • Fever or appears unusually sleepy, difficult to wake, persistently irritable or generally unwell.
  • A red, hot or swollen hip, groin or upper thigh.
  • Sudden severe pain or persistent crying when one hip or leg is moved.
  • Stopped kicking one leg or holds it unusually still.
  • A new deformity, shortening or inability to move the leg after a fall or other injury.

Joint infection and significant injury can damage a young hip quickly. Do not wait for a routine DDH ultrasound; examination, blood tests, urgent imaging and treatment may be needed. DDH itself is usually painless in an infant.

What is Developmental Dysplasia of the Hip?

The hip is a ball-and-socket joint. The rounded femoral head at the top of the thighbone should sit deeply and securely within the acetabulum—the cup-shaped socket in the pelvis. In DDH, the socket may be shallow, the joint may be loose, or the femoral head may be partly or completely outside the socket.

“Developmental” is important: the appearance and stability can change as a baby grows. DDH ranges from mild acetabular immaturity to a dislocatable, subluxed or fully dislocated hip. Early recognition allows the growing joint to be guided into a healthier position.

A Hip Click is Not the Same as a Dislocation

Soft-tissue clicks are common and may be harmless. A definite “clunk,” limited abduction, leg-length difference or unstable examination is more concerning. Ultrasound is interpreted with the examination and risk history; the sound described by a parent does not establish or exclude DDH.

Who May Need an Infant Hip Ultrasound?

Breech presentation A major screening indication, including many babies delivered by caesarean section.
Close family history A parent or sibling who had DDH or treatment for a dislocated baby hip.
Abnormal hip examination Instability, a clunk, limited abduction, asymmetry or leg-length concern.
Treatment monitoring To check hip position and development during a Pavlik harness or another specialist plan.

Other factors that may influence referral include:

  • A history of clinical hip instability during the newborn period, even if the later examination seems normal.
  • A hip that cannot be abducted as widely as the opposite side.
  • Associated packaging conditions such as fixed foot deformity or torticollis, according to local protocol.
  • Low amniotic fluid, female sex and firstborn status as supporting risk context—not automatic scan criteria everywhere.
  • A previous immature or indeterminate ultrasound requiring interval reassessment.

Screening policies differ. Some systems use universal ultrasound; others use repeated physical examination with selective imaging for recognised risk factors. A baby can develop DDH without any known risk factor, so routine hip checks remain important even after a normal scan.

When Should the Scan Be Performed?

Timing depends on the reason for referral, gestational age and local pathway. A stable baby with a risk factor is often scanned at about 4–6 weeks of age or later; some guidance uses a window from 6 weeks to 6 months. Very early scanning can show physiological immaturity that would resolve without treatment.

Abnormal or unstable clinical examination Prompt paediatric orthopaedic assessment is important. Do not postpone referral simply to wait for a routine screening age; the specialist decides the appropriate imaging and timing.
Breech or family-history screening Commonly scheduled after the first few weeks, when transient newborn laxity has reduced but the cartilaginous hip is still well suited to ultrasound.
Premature baby The service may use corrected age, postmenstrual age or a specific interval from the due date. Give both the birth date and expected date of delivery when booking.
Older infant As the femoral head ossifies—often around 4–6 months—radiographs become more useful and ultrasound views less complete. The clinician chooses imaging according to age and development.

A screening appointment is not an emergency. However, a definite unstable hip, new leg asymmetry or delayed development should not be ignored because an earlier scan was normal.

How is This Different From Other Hip Tests?

Physical hip examination Assesses stability, range of abduction, leg length and symmetry. It is repeated as the child grows because no single newborn examination or image detects every case.
Infant hip ultrasound Shows the cartilaginous femoral head, acetabulum and labrum and allows gentle dynamic assessment without radiation. Accuracy depends strongly on positioning and examiner expertise.
Pelvic or hip radiograph Becomes more useful as the femoral head ossifies. It assesses acetabular development and hip position but uses a small dose of ionising radiation and cannot provide real-time stress assessment.
MRI Used selectively, often after reduction and casting, to confirm that the cartilaginous femoral head is seated in the socket when ultrasound or X-ray cannot answer the question fully.
Ultrasound for hip pain or infection A different urgent examination may look for joint fluid. A routine DDH protocol neither replaces sepsis assessment nor excludes septic arthritis in a febrile, painful infant.

What Does the Radiologist Assess?

Femoral head position The largely cartilaginous ball is checked for centring within the acetabulum at rest and, when appropriate, during gentle dynamic positioning.
Bony acetabulum The depth and slope of the developing socket roof are assessed on a correctly aligned coronal image.
Cartilaginous roof and labrum These soft-tissue structures help contain the femoral head and contribute to beta-angle and stability assessment.
Femoral-head coverage The proportion of the femoral head covered by the bony socket is estimated. Adequate coverage supports a centred, developing hip but is not interpreted in isolation.
Alpha and beta angles Graf measurements describe the bony and cartilaginous roof on a standard image. They are valid only when the anatomical landmarks and scan plane meet quality criteria.
Dynamic stability Gentle manoeuvres may assess whether the femoral head remains centred, moves partly out of the socket or can be reduced. Forceful testing is not appropriate.
Both hips The right and left hips are documented separately because DDH can be unilateral or bilateral and the less obvious side may still require assessment.
Change during treatment Follow-up scans assess whether a previously displaced hip is centred and whether acetabular development is improving without altering a harness outside the treatment team's instructions.

Static Graf and Dynamic Assessment

Graf technique Uses a standard coronal image with recognised landmarks to assess morphology and measure alpha and beta angles. The report may assign a Graf type based on age and these features.
Dynamic technique Observes femoral-head motion during gentle positioning and stress. It answers whether the hip is stable, displaceable, subluxed, dislocated or reducible.
Combined assessment Many complete studies use both morphology and stability because a well-centred but shallow socket and a morphologically immature but unstable hip require different interpretation.

Parents should not try to reproduce stress manoeuvres or compare online images. The scan is operator-dependent, and incorrect position can create misleading angles or apparent instability.

How Should I Prepare My Baby?

No fasting, sedation or medicine change is needed. A calm, recently fed baby who can be positioned comfortably usually produces the clearest study.

Feeding Feed normally. If practical, plan a feed shortly before the appointment and bring milk or feeding supplies in case your baby needs settling during the visit.
Clothing and nappy Choose loose clothing that opens easily at the waist and legs. The nappy may be loosened or folded down while each hip is scanned.
Comfort items Bring a blanket, dummy or familiar soothing item. A parent or caregiver normally remains beside the baby and can help with calm holding.
Pavlik harness or brace Do not remove, loosen or adjust it unless the orthopaedic team specifically instructed you. Bring written treatment guidance and tell the imaging team when it was fitted.
Previous records Bring earlier hip ultrasound or X-ray reports and the child-health record. Give the birth date, due date, breech history, family history and findings from previous examinations.
  • Allow time for feeding, changing and settling rather than arriving with a hungry baby.
  • Mention whether the baby was breech at any time in late pregnancy, even after a caesarean delivery.
  • For a premature baby, provide the gestational age at birth and expected due date.
  • Tell the team if the baby has fever, pain, leg swelling or has stopped moving one leg before the scan.
  • Do not practise hip-opening or stress manoeuvres at home.

What Happens During the Scan?

1 The referral and age are confirmed

The radiologist reviews the screening indication, birth presentation, family history, examination findings, corrected age and any previous treatment.

2 Your baby is positioned securely

The baby is usually placed on one side in a supportive cradle or against a caregiver, with the hip and knee comfortably bent. No sedation is required.

3 A small probe is placed over the outer hip

Warm gel and a high-frequency probe create real-time images. The probe remains on the skin and does not enter the joint.

4 Standard landmarks are aligned

The radiologist obtains a reproducible coronal image showing the ilium, acetabular roof, femoral head and labrum before accepting measurements.

5 Stability is assessed gently when indicated

Real-time views may be taken while the leg is carefully repositioned. This should not hurt and does not involve forceful manipulation.

6 The other hip is examined

The baby is turned safely and the same image set is obtained on the opposite side. Each hip is reported separately.

The scan commonly takes 15–30 minutes. Most of that time may be spent positioning and soothing rather than scanning. Crying does not harm the hip, but strong movement can make precise measurements harder and may require a pause.

What Do Common Report Terms Mean?

Mature / normal hip The femoral head is centred and stable, with age-appropriate bony socket development and coverage on a technically satisfactory examination.
Physiologically immature hip The hip is located but the socket is not yet fully mature for the chosen classification. In a young infant this often improves naturally, so age and repeat imaging determine its importance.
Graf type IIa A commonly used term for an immature, located hip in an infant younger than three months. Subclassification, age, stability and progress decide whether observation or treatment is appropriate.
Alpha angle Reflects the slope and development of the bony acetabular roof. An angle of 60° or more is commonly part of a mature Graf type I pattern, but the complete image and classification still matter.
Beta angle Relates to the cartilaginous roof and labrum. It supplements rather than replaces alpha-angle, coverage and stability assessment.
Femoral-head coverage The percentage of the femoral head contained by the bony acetabulum. Thresholds depend on technique and clinical context and should not be interpreted from a single screenshot at home.
Acetabular dysplasia The socket is shallower or less developed than expected, providing inadequate bony support to the femoral head.
Subluxable / subluxed The femoral head can move partly out of the socket during gentle assessment or already rests partly displaced.
Dislocatable / dislocated The femoral head can move completely out of the socket or is already outside it. Prompt paediatric orthopaedic management is required.
Reducible A displaced femoral head can be guided back into the socket during specialist dynamic assessment. Parents should never attempt this manoeuvre.
Technically limited Motion, positioning, an older ossified femoral head, a cast or another factor prevented reliable landmarks or measurements. Repeat imaging or an X-ray may be recommended.

What Can Infant Hip Ultrasound Not Determine Reliably?

  • That every early immature hip will remain dysplastic without an age-appropriate follow-up examination.
  • That a normal scan permanently excludes later dysplasia when examination findings or high-risk follow-up remain concerning.
  • The exact future hip function or need for surgery from a single early image.
  • Reliable Graf angles when the standard landmarks and probe plane are not correct.
  • The complete bony anatomy after substantial femoral-head ossification, when radiography is usually preferred.
  • Septic arthritis in a febrile, painful infant using only a routine DDH protocol.
  • Whether treatment should be started, adjusted or stopped without paediatric orthopaedic review.
  • That symmetric skin creases alone prove both hips are normal.

Ultrasound is one part of an ongoing screening pathway. Hip examination should continue during routine child-health visits, and new limited abduction, leg-length difference or gait asymmetry needs reassessment.

What Happens After the Scan?

Normal mature and stable hips Usually return to routine clinical hip checks. Some high-risk pathways—particularly after breech presentation— may still recommend later examination or radiography, so follow the referring team's plan.
Immature but located hip Often receives repeat ultrasound after an interval to confirm maturation. Not every immature hip requires a harness, especially in the youngest babies.
Dysplastic or unstable hip Requires prompt paediatric orthopaedic assessment. Early treatment commonly uses a Pavlik harness or another brace to hold the hips flexed and gently abducted while allowing movement.
Follow-up during treatment Ultrasound checks whether the femoral head remains reduced and whether socket development is improving. Only the orthopaedic team should change harness straps or wear schedule.
Older infant or incomplete views A pelvic radiograph or specialist imaging may be recommended instead of repeatedly attempting an inadequate ultrasound.

Early treatment is often effective, but follow-up matters because the socket continues to develop. Keep the orthopaedic and imaging appointments even when your baby appears comfortable and kicks both legs normally.

Hip-Healthy Positioning and Swaddling

A baby's hips naturally rest with the thighs bent and gently apart. Swaddling may wrap the upper body securely, but the hips and knees should have room to flex and move. Do not bind the legs straight and tightly together.

  • Allow the thighs to bend upwards and move outwards within the wrap or sleep sack.
  • Choose carriers that support the thighs rather than leaving both legs hanging straight down for prolonged periods.
  • Follow safe-sleep guidance as well as hip-positioning advice; hip-healthy wrapping does not replace sleep-safety precautions.
  • Do not use double or triple nappies as treatment unless a specialist gives a specific reason.
  • Never alter a Pavlik harness to imitate a swaddle or make the legs look more symmetrical.

Myth vs Fact

Myth A baby who kicks both legs cannot have DDH.
Fact DDH is usually painless, and many babies move both legs normally. Screening uses risk history, repeated examination and selective imaging rather than appearance alone.
Myth Every hip click means the joint is dislocated.
Fact Benign soft-tissue clicks are common. A definite clunk, instability or limited abduction needs proper assessment; sound alone does not give the diagnosis.
Myth The earliest possible ultrasound is always best.
Fact Many newborn hips are temporarily immature or lax. Unless the examination is abnormal, waiting several weeks can reduce false-positive findings and unnecessary treatment.
Myth Double nappies treat a shallow or unstable hip.
Fact Double nappies do not provide controlled treatment and can delay appropriate care. A fitted harness or brace should be used only under the orthopaedic team's supervision.
Myth Tight straight-leg swaddling is harmless.
Fact Restricting the legs in extension can impair healthy hip positioning. The knees and hips need room to bend and move apart.

Frequently Asked Questions

Does my baby need to fast?

No. Feed normally. A recently fed, comfortable baby is often easier to position and does not need sedation.

Will the scan hurt?

No. The probe moves over the skin with gel, and the hips are positioned gently. Babies may cry because they dislike being undressed or held still, not because ultrasound itself is painful.

Why are both hips scanned when only one seemed abnormal?

DDH can affect either or both sides, and clinical asymmetry does not always identify the more abnormal hip. Documenting both sides provides a complete baseline.

Does a breech baby still need screening after a caesarean birth?

Often yes. The risk is related mainly to breech positioning in the uterus, not simply passage through the birth canal. Follow the newborn team's referral protocol even after an elective caesarean delivery.

What if my baby was premature?

Timing varies. Give the hospital both the birth date and expected due date because corrected or postmenstrual age may be used to avoid interpreting expected immaturity as dysplasia.

Why does an immature hip need another scan?

Many immature hips develop normally, but repeat imaging confirms that the socket has matured and the femoral head remains centred. The interval depends on age and the initial morphology and stability.

Should I remove the Pavlik harness for ultrasound?

Not unless the orthopaedic or imaging team specifically tells you to. Staff use the required protocol without parents changing strap length or hip position themselves.

Does a normal ultrasound mean no more hip checks are needed?

No. Routine physical hip examinations continue as the child grows. Selected high-risk pathways may also recommend later imaging even after a normal early ultrasound.

Why might an older baby need an X-ray instead?

As the femoral head ossifies, bone blocks part of the ultrasound view but becomes visible on radiography. The most informative test therefore changes with age and skeletal development.

When will we receive the result?

The radiologist prepares a report for the referring clinician. An unstable or clearly dysplastic hip is linked promptly to paediatric orthopaedic review. Ask how and when the result and follow-up plan will be discussed.

Related Ultrasound Guides

The correct ultrasound protocol depends on age, anatomy and the exact clinical question on the referral.

Radiology Antenatal Ultrasound Pregnancy Scans / Fetal Assessment Read scan guide → Radiology Neonatal Cranial Neurosonography Cranial Ultrasound / Infant Head Scan Read scan guide → Radiology Abdominal Ultrasound USG Abdomen / Upper-Abdominal Scan Read scan guide → Radiology Soft-Tissue Lump Ultrasound Superficial Lump / USG Soft Tissue Read scan guide →

A Note From Our Doctors

The information on this page is intended to help you understand your condition. It should not be considered a diagnosis or a substitute for a consultation with a qualified medical professional.

Every patient is unique. The same symptom can have different causes in different individuals, and the most appropriate investigations and treatment depend on your medical history, examination findings, age, existing medical conditions and test results.

At SR Speciality Hospital, we believe in treating the whole patient—not just a symptom, scan or laboratory report. Every treatment plan is individualised after careful medical evaluation.

Paediatric Radiology Appointments

Has your baby been referred for hip ultrasound?

Contact the hospital with the birth date, expected due date, breech history, family history and examination findings. Mention whether your baby already wears a Pavlik harness or another brace.

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