Paediatric hip disorder post-pic

Paediatric Hip Disorders

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Common hip symptoms in children include pain in the hip or a limp.Β However, some children may have difficulty localising the pain and thus complain of pain in their groin, knee or leg.1Β 

In all patients, a thorough history and examination of the hip should be undertaken.

This article will provide an overviewΒ of the anatomy of the hip and the common paediatric hip disorders.

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Anatomy of the hip

The hip is a ball-in-socket joint that provides the movements of flexion, extension, abduction, adduction, internal and external rotation and circumduction.

The head of the femur sits in the acetabulum, joined centrally by the ligamentum teres (ligament of the head of the femur), carrying the acetabular branch of the obturator artery.

The acetabular fossa is lined by the acetabular labrum, joined inferiorly by the transverse acetabular ligament. Surrounding these structures is the synovial joint capsule (Figure 1).

Three external ligaments support the hip, the iliofemoral, ischiofemoral and pubofemoral ligaments. These areΒ named respectively for the part of the hip bone from which they originate, and their insertion into the femur.

Developmental dysplasia of the hip (DDH)

DDH is a disorder of abnormal development resulting in dysplasia and potential subluxation or dislocation of the hip secondary to capsular laxity and mechanical factors.4,5

DDH is the most common abnormality in newborn infants. Due to the nature of how the baby sits in the womb, the left hip is more commonly affected.4,5

Risk factors

The exact cause of DDH is unknown but risk factors for DDH include:

  • Family history of DDH
  • Breeched baby
  • Female sex
  • Fixed foot deformity
  • Torticollis

There is no singular way to prevent DDH. The incidence of DDH may be influenced by local child-rearing practices, as certain swaddling and baby-carrying techniques have been shown to correlate with a decline in this disorder.6

Clinical features

If DDH is suspected, an examination of the hip should be undertaken. In addition, screening examinations are performed as part of routine baby checks.Β 

Findings in 3-6-month-olds include leg length discrepancy and limitations in hip abduction due to contractures.

In older children (> 1 year), a Trendelenburg gait and toe walking may also be seen.

Further clinical findings at any age may include:

  • Asymmetrical buttock creases
  • Hip locking/clicking
  • Pain

The Ortolani and Barlow tests are used to screen babies for hip dysplasia.Β 

Ortolani and Barlow tests

Barlow’s testΒ is performed byΒ adducting the hipΒ (bringing the thigh towards the midline) whilstΒ applying light pressure on the kneeΒ with your thumb, directing the forceΒ posteriorly.Β 

If the hip isΒ unstable, theΒ femoral head will slip over the posterior rim of the acetabulum, producing aΒ palpable sensationΒ ofΒ subluxationΒ orΒ dislocation.

If theΒ hipΒ isΒ dislocatableΒ the test is consideredΒ positive.Β 

Ortolani’s test is then used to confirm posterior dislocation of the hip joint.Β 

For more information, see the Geeky Medics guide to performing a newborn baby assessment.Β 


Relevant investigations include:

  • Ultrasound: can be performed in infants less than 4-6months old
  • AP pelvic X-ray: should be performed in children greater than 4-6months old, when the femoral head ossification centre is visible (Figure 3)


Management of DDH depends on the age of the patient:7

  • Under 6 months: Pavlik harness
  • 6 – 18 months (or failure of Pavlik harness): closed reduction and spica casting
  • Greater than 18 months (or failure of closed reduction): operative management (open reduction and hip reconstruction)


Complications of DDH include:

  • Recurrence
  • Transient femoral nerve palsy with excessive flexion during Pavlik bracing
  • Avascular necrosis: due to retrograde femoral head blood flow. Most commonly affects the median circumflex femoral artery.
Shenton's lines
Figure 3. Key radiographic lines to check during Investigation for DDH.8 In a normal hip, Hilgenreiner’s and Perkin’s lines should intersect at the corner of the femoral head (right). In a normal hip, Shenton’s line should be a smooth, curved connection from the lesser trochanter, along the femoral neck to the pubis, with no step-off (right).

Legg-Calve-Perthes disease

Legg-Calve-Perthes disease (also called Perthes disease) causes idiopathic avascular necrosis of proximal femoral epiphysis in children.7


In the United Kingdom, the incidence of Legg-Calve-Perthes disease is 7.8 per 100,000 children aged 0-14.10Β 

Risk factors

The exact cause is unknown, risk factors include:

  • Age 4-10
  • Male
  • Family history
  • Caucasian

Clinical features

Clinical examination findings may include:

  • Limp (can be painless)
  • Hip stiffness with loss of internal rotation and abduction
  • Pain
  • Antalgic gait
  • Muscle spasms
  • Leg length discrepancy (late finding)


A bilateral AP pelvic x-ray and ‘frog-leg’ lateral X-ray are used to diagnose Perthes disease (Figure 5).

A bone scan or MRI may be useful if the diagnosis is unclear. They can also provide information on the extent of femoral head involvement.

Radiographic findings

Key radiographic signs of Perthes disease include:11

  • Asymmetrical femoral epiphyseal size
  • Increased density of femoral head epiphysis
  • Radiolucency
  • Coxa plana: femoral head widening and flatting (shown in Figure 4)
  • Coxa magna: proximal femoral neck deformity
  • ‘Sagging rope sign’: thin sclerotic line running across the femoral neck

*Crescent’s sign is a specific finding on a radiograph in late stages of the disease and represents a subchondral fracture.

Perthes disease x-ray
Figure 4. Radiographic appearance of Perthes disease in the left hip. Note the prominent coxa plana.11



Conservative management options include:

  • Observation
  • Activity limitation
  • Physiotherapy
  • Analgesia: NSAIDs
  • Casting and bracing


Surgery (osteotomy) is considered, based on the patient’s age, radiographic findings and clinical features.

The following would increase the likelihood of the need for surgical intervention:9

  • Age over eight years old
  • More than 50% of the femoral head is damaged
  • Nonsurgical management has been unsuccessful


Complications of Legg-Calve-Perthes disease include:12

  • Osteoarthritis
  • General joint stiffness and immobility
  • Premature physeal arrest, degenerative arthritis
  • Acetabular dysplasia
  • Unequal, shortened limb length

Slipped capital femoral epiphysis (SCFE)

SCFE occurs when the metaphysis of the femur displaces anteriorly and superiorly, leading to the displacement of the capital femoral epiphysis.13

SCFE is the most common hip disorder in adolescents.14

Risk factors

The exact cause of SCFE is unknown but risk factors include:

  • Male
  • Obesity: increases stress on physis
  • Puberty/endocrine disorders: hormones weaken physis, making it more prone to displacement
  • Previous radiotherapy

Clinical features

Clinical features of SCFE include:

  • Pain
  • Abnormal leg alignment: external rotation
  • Abnormal gait/limp: may have Trendelenburg gait
  • Decreased range of movement
  • Weakness and muscle atrophy


SCFE is diagnosed by obtaining bilateral AP pelvic x-rays, along with a frog-leg lateral X-ray (Figure 5).

Thyroid function tests or growth hormone may be considered in the presence of a conjunctive endocrine disorder.

Slipped capital femoral epiphysis (SCFE) x-ray
Figure 5. Radiographic Appearance of SCFE.Β  A) AP x-ray showcasing Klein’s line.16 SCFE is suspected if Klein’s line does not intersect with the femoral head. B) Frog-leg lateral x-ray of SCFE. Note the displaced Klein’s line (red).17


Management of SCFE is usually surgical.

Options include:

  • In situ fixation of the epiphysis with a screw
  • Bone graft epiphysiodesis
  • Spica cast
  • In situ fixation with multiple pins


Complications of SCFE include:15

  • Chondrolysis
  • Late deformity
  • SCFE in the contralateral hip
  • Osteonecrosis
  • Infection
  • Chronic pain
  • Degenerative arthritis
  • Pin associated fracture

Transient synovitis

Transient synovitis is an intermittent inflammatory disorder of the synovium of the hip, common in paediatric populations.18

Up to three percent of children have an episode of transient synovitis at some point during their life.18

Risk factors

The exact cause of transient synovitis is unknown. However, many children develop the disease secondary to a viral upper respiratory infection.

Clinical features

Clinical features of transient synovitis include:

  • Hip presents in flexion, abduction and external rotation
  • Limited range of motion: most commonly, hip abduction
  • Limp
  • Pain
  • Muscle spasms


Relevant laboratory investigations include:

  • Full blood count: raised white cell count
  • Inflammatory markers (CRP, ESR): will be raised

Relevant imaging investigations include:

  • AP, lateral or frog-leg X-ray to rule out other paediatric hip disorders
  • Ultrasound can be performed if there is suspicion of septic arthritis

The most important differential diagnosis to rule out is septic arthritis. Therefore, always review Kocher’s criteria and perform an ultrasound if there is clinical suspicion of this severe pathological process.19


Transient synovitis is a self-limiting disorder that typically lasts 7-10 days, therefore management is focused on relieving the patient’s symptoms:

  • Bed rest (short period)
  • Activity restriction
  • Analgesia: paracetamol and NSAIDs.


There are rarely any complications of transient synovitis.


Conditions by age

The signs and symptoms of the various paediatric hip disorders often overlap. It is beneficial to think about each condition in the context of the age range most commonly affected:20

  • Age 0 – 4: DDH
  • Age 4 – 10: Perthes disease, transient synovitis
  • Age 10 – 16: SCFE

Summary table

Table 1. Summary of common paediatric hip disorders

Condition Risk factors Investigations Management
  • Female
  • Breech delivery
  • Family history
  • <4-6 months: ultrasound
  • 4-6 months: X-ray
  • <6 months + reducible hip: Pavlik harness
  • Male
  • Caucasian
  • AP pelvic X-ray
  • ‘Frog-leg’ lateral X-ray
  • May be non-surgical or surgical depending on patient factors
  • Male
  • Obese
  • Endocrine disorder
  • AP pelvic X-ray
  • ‘Frog-leg’ lateral X-ray
  • Always surgical
Transient synovitis
  • Usually follows upper respiratory tract infection
  • Ultrasound if suspicion of septic arthritis
  • Self-limiting: rest and analgesia


Miss Kirsty MacLeod

Orthopaedic Registrar


Dr Chris Jefferies


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