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Hip symptoms are a common source of secondary care referrals from primary care. Common presenting complaints include pain in the hip or a limping child.1 However, some children may have difficulty localising the pain and thus complain of pain in their groin, knee or leg. In all patients, a thorough history and examination of the hip should be undertaken. Here, we have compiled a list of the most common paediatric hip disorders you are likely to see or discuss on your orthopaedic surgery rotation.

 


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 – iliofemoral, ischiofemoral, pubofemoral- named respectively for the part of the hip bone from which they originate, and their insertion into the femur. An x-ray will usually be sought for a child presenting with a hip problem, therefore it is important to also have a basic understanding of radiographic anatomy (Figure 2).

 

Hip joint anatomy

Figure 1. General Anatomy of the Hip Joint.2

 

 

Hip joint x-ray

Figure 2. Radiographic Bony Features of the Pelvis and Hip.3 Key features to be aware of in the presentation of a paediatric hip disorder are the acetabulum, femoral head and the femoral neck.

 


Developmental Dysplasia of the Hip (DDH) 4

What is it?

A disorder of abnormal development resulting in dysplasia and possible subluxation or dislocation of the hip secondary to capsular laxity and mechanical factors.5

 

Epidemiology

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 DDH is more commonly seen in Native Americans and Laplanders.

 

Risk Factors

The exact cause of DDH is unknown but there are many risk factors associated with it, including:

  • Family history of DDH
  • Breeched baby
  • Female baby- more sensitive to mother’s hormones that make ligaments lax
  • Fixed foot deformity- less space in the womb
  • Torticollis- less space in the womb

 

Prevention

There is no singular way to prevent DDH. Interestingly though, in some cultures, 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

 

Examination Findings

If DDH is suspected, an examination of the hip should be undertaken. Findings in 3-6-month-olds include: leg length discrepancy and limitations in hip abduction due to contractures. In older children (>1year), a Trendelenburg gait and toe walking may also be seen. Further findings at any age include:

  • Asymmetrical buttock creases
  • Hip locking/clicking
  • Pain

Screening

The Ortolani and Barlow tests are used to screen babies for hip dysplasia at 3-6 months old (Figure 3).

Investigations

An ultrasound can be performed in infants less than 4-6months old, while an antero-posterior (AP) pelvic radiograph should be performed in children greater than 4-6months old, when the femoral head ossification centre is visible (Figure 4).

Management 7

Less than 6 months old

  • Pavlik Harness

 

6-18months old or failure of Pavlik Harness

  • Closed Reduction and Spica Casting

 

Greater than 18 months old or failure of closed reduction

  • Operative management (open reduction + hip reconstruction)

Complications

  • Recurrence
  • Transient femoral nerve palsy with excessive flexion during Pavlik bracing
  • Avascular necrosis. Why? Because of retrograde femoral head blood flow. Most commonly affects the median circumflex femoral artery.

 

Figure 3. DDH Screening tests. The Ortolani and Barlow screening tests for DDH are performed at the 3-6month infant check-up.

 

 

Shenton's lines

Figure 4. 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 (Perthes) Disease 9

What is it?

Idiopathic avascular necrosis of proximal femoral epiphysis in children.

 

Epidemiology

In the UK, the incidence of Legg-Calve-Perthes disease is 7.8 per 100,000 children aged 0-14. 10 

 

Risk Factors

The exact cause of Perthes disease is unknown but there are some risk factors associated with it, including:

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

 

Examination Findings

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

 

Investigations

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 can sometimes also be used if the diagnosis is unclear. This can also provide information on the extent of femoral head involvement. 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 clearly in Figure 5)
  • 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 radiograph in late stages of the disease and represents a subchondral fracture.

 

Management

Non-surgical

  • Observation
  • Limit activity
  • Physiotherapy
  • NSAIDs
  • Casting and bracing

Surgical

Surgery (osteotomy) is considered by the orthopaedic surgeon, based upon the patient’s age, radiographic findings and clinical features. The following would increase the likelihood of the need for surgical intervention:9

  • >8y/o
  • >50% femoral head damaged
  • Nonsurgical management has been unsuccessful

 

Complications 12

  • Osteoarthritis
  • General joint stiffness and immobility
  • Premature physeal arrest, degenerative arthritis
  • Acetabular dysplasia
  • Unequal, shortened limb length
Perthes disease x-ray

Figure 5. Radiographic Appearance of Perthes Disease.11 Perthes disease in the left hip. Note the prominent coxa plana.

 


Slipped Capital Femoral Epiphysis (SCFE) 13

What is it?

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

 

Epidemiology

SCFE is the most common hip disorder in adolescents. 14

Risk Factors

The exact cause of SCFE is unknown but there are some risk factors associated with it, including:

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

 

Examination Findings

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

 

Investigations

SCFE is diagnosed by obtaining bilateral AP pelvic x-rays, along with a frog-leg lateral x-ray (Figure 6). You may wish to consider ordering hormone blood tests like TFTs or GH in the presence of a conjunctive endocrine disorder.

 

Management

Always surgical

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

 

Complications 15

  • Chondrolysis
  • Late deformity
  • SCFE in the contralateral hip
  • Osteonecrosis
  • Infection
  • Chronic pain
  • Degenerative arthritis
  • Pin associated fracture
Slipped capital femoral epiphysis (SCFE) x-ray

Figure 6. Radiographic Appearance of SCFE.  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.17 Note the displaced Klein’s line (red).

 


Transient Synovitis 18

What is it?

An intermittent inflammatory disorder of the synovium of the hip, common in paediatric populations.

 

Epidemiology

Up to 3% 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.

 

Examination Findings

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

 

Investigations

  • Bloods:
    • FBC- ↑WCC (>12,000cells/mm3)
    • ↑ ESR, CRP for inflammation
  • 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

*Note- 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

 

Management

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 time)
  • Activity modification
  • NSAIDs

*Avoid aspirin in children due to the risk of Reye’s syndrome

 

Complications

There are rarely any complications of transient synovitis.

 


Age-Related Pathology

The signs and symptoms of the various paediatric hip disorders often overlap. In order to help distinguish between pathologies during exams and OSCEs, it is beneficial to think about each condition in the context of the age range most commonly affected (Table 1).

Table 1. Breakdown of Common Paediatric Hip Disorders by Age Range 20

0-4y/o4-10y/o10-16y/o
DDHPerthes
Transient Synovitis
SCFE

 


Summary Table

Below find a brief summary table of the common paediatric hip disorders we have discussed (Table 2). Use this summary table as a non-exclusive, quick review for revision purposes. Common symptoms experienced across all conditions are pain and/or limping.

Table 2. Summary of Common Paediatric Hip Disorders

PathologyRisk factorsInvestigationsManagement
DDHFemale, breeched, family hx<4-6 months = U/S
>4-6 months = X-Ray
<6 months + reducible hip = Pavlik harness

6-18 months or failure of harness = closed reduction + casting

>18 months or failure of closed reduction = operative
PerthesMale, CaucasianAP Pelvic X-Ray
Frog-Leg Lateral X-Ray
May be non-surgical or surgical depending on patient factors
SCFEMale, obese, endocrine disorderAP Pelvic X-Ray
Frog Leg X-Ray
Always surgical
Transient SynovitisURTIFBC, ESR, CRP
US if suspicion of septic arthritis
Rest, NSAIDs

 


Reviewed by

Miss Kirsty MacLeod

Orthopaedic Registrar

 


References

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  2. No Title [Internet]. Wikimedia Commons. 2013 [cited 2018 Sep 17]. Available from: https://commons.wikimedia.org/wiki/File:Slide2DAD.JPG
  3. Pelvis Radiographic Anatomy [Internet]. WikiRadiology. 2018 [cited 2018 Jul 22]. Available from: http://www.wikiradiography.net/page/Pelvis+Radiographic+Anatomy
  4. Developmental Dysplasia of the Hip (DDH) [Internet]. International Hip Dysplasia Institute. 2018 [cited 2018 Jul 22]. Available from: https://hipdysplasia.org/developmental-dysplasia-of-the-hip/
  5. DDH (Developmental Dysplasia of Hip) Flashcards Preview [Internet]. Brainscape. 2018 [cited 2018 Sep 13]. Available from: https://www.brainscape.com/flashcards/ddh-developmental-dysplasia-of-the-hip-3887136/packs/5239004
  6. Loder RT, Skopelja EN. The Epidemiology and Demographics of Hip Dysplasia. ISRN Orthop [Internet]. 2011;2011:1–46. Available from: http://www.hindawi.com/journals/isrn/2011/238607/
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  8. Noordin S, Umer M, Hafeez K, Nawaz H. Developmental dysplasia of the hip. Orthop Rev (Pavia) [Internet]. 2010;2(2):19. Available from: http://www.pagepress.org/journals/index.php/or/article/view/or.2010.e19
  9. Perthes Disease [Internet]. OrthoInfo. 2018 [cited 2018 Jul 22]. Available from: https://orthoinfo.aaos.org/en/diseases–conditions/perthes-disease/
  10. Perry DC, Bruce CE, Pope D, Dangerfield P, Platt MJ, Hall AJ. Legg-Calvé-Perthes disease in the UK: Geographic and temporal trends in incidence reflecting differences in degree of deprivation in childhood. Arthritis Rheum. 2012;64(5):1673–9.
  11. Matt Skalsi FG et al. Perthes Disease [Internet]. Radiopaedia. 2018 [cited 2018 Jul 22]. Available from: https://radiopaedia.org/articles/perthes-disease
  12. Souder C. Legg-Calve-Perthes Disease [Internet]. OrthoBullets. 2018 [cited 2018 Sep 13]. Available from: https://www.orthobullets.com/pediatrics/4119/legg-calve-perthes-disease-coxa-plana
  13. Loder RT. Slipped Capital Femoral Epiphysis [Internet]. BMJ Best Practice. 2018 [cited 2018 Jul 22]. Available from: https://bestpractice.bmj.com/topics/en-us/757?q=Slipped capital femoral epiphysis&c=suggested
  14. Peck D. Slipped capital femoral epiphysis: Diagnosis and management. Am Fam Physician. 2010;82(3):258–62.
  15. Bassett A. Slipped Capital Femoral Epiphysis [Internet]. OrthoBullets. 2018 [cited 2018 Sep 13]. Available from: https://www.orthobullets.com/pediatrics/4040/slipped-capital-femoral-epiphysis
  16. Slipped Capital Femoral Epiphysis [Internet]. The Orthopaedic Knowledge Network. 2018 [cited 2018 Jul 22]. Available from: https://www.orthopaedicsone.com/pages/viewpage.action?pageId=30507338
  17. Slipped Capital Femoral Epiphysis [Internet]. Wikipedia. 2018 [cited 2018 Jul 22]. Available from: http://www.wikidoc.org/index.php/Slipped_capital_femoral_epiphysis
  18. James McCarthy JD. Transient synovitis of the hip [Internet]. BMJ Best Practice. 2018 [cited 2018 Jul 22]. Available from: https://bestpractice.bmj.com/topics/en-gb/761
  19. Evan Watts ES. Transient Synovitis of Hip [Internet]. OrthoBullets. 2018 [cited 2018 Sep 13]. Available from: https://www.orthobullets.com/pediatrics/4030/transient-synovitis-of-hip
  20. Hip pathology in children [Internet]. Radiology Assistant. 2015 [cited 2018 Jul 22]. Available from: http://www.radiologyassistant.nl/en/p557dccf34fb1a/hip-pathology-in-children.html

 

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