Synonym: congenital dislocation of hip (CDH)

Developmental dysplasia of the hip (DDH) was formerly referred to as congenital dislocation of hip. DDH is now the preferred term to reflect that DDH is an ongoing developmental process, which is variable in presentation and not always detectable at birth. Developmental dysplasia of the hip refers to a spectrum of severity ranging from mild acetabular dysplasia with a stable hip, to more severe forms of dysplasia with neonatal hip instability, to established hip dysplasia with or without later subluxation or dislocation.

There is a suggestion that the national screening programme in the UK, which has operated since 1969, has not resulted in any fewer operations for late disease.¹ Even the use of ultrasound has failed to improve the situation.² It may be that the use of more experienced clinicians in the screening programme, rather than very junior doctors, produces better results.³

Epidemiology

• Developmental dysplasia of the hip affects 1-3% of newborns and is responsible for 29% of primary hip replacements in people up to the age of 60 years.⁴
• A systematic review of unscreened populations estimated the prevalence of clinically diagnosed, established hip dysplasia to be 1.3 per 1,000 but, in populations screened clinically with Ortolani and Barlow tests, the prevalence is higher at 1.6-28.5 per 1,000 and it is higher still with ultrasound screening.⁴
• The left hip is dislocated more often than the right and 20% of cases are bilateral.
• It is more common in cultures that use swaddling of babies, forcing the hips into extension and adduction.⁵

Risk factors

• Positive family history of the condition increases the risk in a manner suggestive of multifactorial inheritance.⁶
• Having a sibling with hip dysplasia increases risk by 5%.
• About 80-85% are female.
• About 60% of cases are first-born, compared with about 40% of all babies.
• Vaginal delivery of babies with breech presentation is associated with a 17-fold increased risk of hip dysplasia; there is a 7-fold increase for breech babies delivered by elective Caesarean section.⁴
• Restriction of movement as with oligohydramnios increases the risk.
• The risk is also increased in multiple pregnancy and prematurity.
• It is more common with neuromuscular disorders, such as cerebral palsy, meningomyelocele and arthrogryposis.

Screening

• Screening for congenital dislocated hip and developmental dysplasia of the hip is part of the physical examination of newborn and 6-8 week-old babies.
• Ultrasound screening is not recommended as a screening tool for all babies.⁷

Examination

Asymmetrical skin folds are found in 25% of normal babies and therefore not an important clinical finding in isolation.

Under 3 months old

• The Ortolani and Barlow tests are the most common clinical tests for newborn babies.
• In the Ortolani test, the examiner applies forward pressure to each femoral head in turn, in an attempt to move a posteriorly dislocated femoral head forwards into the acetabulum. Palpable movement suggests that the hip is dislocated or subluxed, but reducible.
• In the Barlow test, backward pressure is applied to the head of each femur in turn, and a subluxable hip is suspected on the basis of palpable partial or complete displacement.⁸
• Both the Barlow and Ortolani tests detect an unstable hip but do not detect a dislocated, irreducible hip, which is best detected by identifying limited abduction of the flexed hip) or a stable hip with abnormal anatomy, e.g. acetabular dysplasia.
• Benign hip clicks, resulting from soft tissues snapping over bony prominences during hip movement, should be distinguished from the clunks produced during the Ortolani manoeuvre as the dislocated femoral head is reduced and from the subluxation felt during the Barlow test.
• The Barlow and Ortolani tests are useful in neonates but become difficult by 2-3 months of age.
• Stable hips may be dysplastic. Limited hip abduction (less than 60°) when the hip is flexed to 90° is the most important sign of a dislocated or dysplastic hip.⁴

Children aged 3 to 6 months

• The physical signs are rather different and so are the requirements of examination.
• If the hip is dislocated it is in a fixed position.
• The Galeazzi sign:
  • The child is examined lying supine with the hips and knees flexed to 90° and the height of each knee is compared.
  • Unilateral femoral shortening may signify hip dislocation or rarer abnormalities of the femur.
  • False negative results may occur with bilateral hip dysplasia or when the pelvis is not level.
  • A positive sign is that one leg appears shorter than the other.
  • This is usually due to dislocation of the hip; however, any discrepancy of limb length will produce a positive sign.
• Other physical signs for late dislocation include asymmetry of the gluteal thigh or labral skin folds, discrepancy in leg length, a widened perineum on the affected side, buttock flattening, and asymmetrical thigh skin folds, decreased abduction on the affected side, and standing or walking with external rotation of the affected leg.

Older children⁴

• Limited abduction when fully flexed.
• May walk on toes on the affected side or present with a painless limp.

Bilateral dislocation of the hip

• Can be quite difficult to diagnose, especially after the neonatal period.
• There is often a waddling gait with hyperlordosis.
• The Galeazzi sign for hip shortening is often absent as are asymmetrical thigh and skin folds, or asymmetrically decreased abduction.
• Careful examination is needed with a high level of suspicion.

Investigations

• Dynamic ultrasound is used to assess hip stability and acetabular development in infants.
• It is the technique of choice and has even been suggested as a universal screening procedure.⁹
• Ultrasound helps diagnosis in children under 4.5 months but pelvic X-rays are more useful in older infants and children.⁴
• Arthrography, CT and MRI scanning may also be needed.

Management

Early diagnosis and treatment of those most severely affected is important for a good outcome.⁴ Most unstable hips stabilise spontaneously by 2-6 weeks of age and any hip that remains dislocatable or pathologically unstable after this time requires prompt treatment.

• Bracing is first-line treatment in children younger than 6 months. Surgery is an option for children in whom nonoperative treatment has failed and in children diagnosed after 6 months of age.¹⁰
• It is important to diagnose developmental dysplasia of the hip early to improve treatment results and to decrease the risk of complications.¹⁰
• However, early detection and treatment does not entirely avoid the need for subsequent surgery, and surgery is needed by up to 5% of infants treated with abduction splinting.¹¹
• The indications for the various procedures and the most effective management interventions remain controversial.

Nonsurgical management⁴

• A dynamic flexion-abduction orthosis (Pavlik® harness), left in place at all times, is used to maintain hip reduction.
• The harness can be adjusted as the child grows and the hip stabilises.
• One study showed that when harness treatment was started by 90 days of age, only 5.7% of babies required further treatment.
• The main risks of splinting are avascular necrosis and a temporary femoral nerve palsy.
• Harness or splint treatment is much less successful if it is started after the age of 6-8 weeks.
• A Pavlik® harness is contra-indicated in children older than 4.5-6 months and when the hip is irreducible.
• Several small studies have shown that stable hips with mild dysplasia can be observed safely for six weeks before a decision to treat is made.

Surgery⁴

• Surgery is indicated for those who do not respond to early splint or harness treatment, and those who are diagnosed late and are not suitable for splint or harness treatment.
• The most common operation is closed reduction with adductor or psoas tenotomy, followed by 3-4 months in a plaster cast or abduction brace.
• The older the child, the more likely an extensive procedure will be required with open reduction and soft tissue stabilisation of the joint, followed by a cast.
• Over the age of 18-24 months, an additional pelvic and/or femoral osteotomy is often required.

Complications

• Surgery can result in a number of complications including re-dislocation, stiffness, blood loss and avascular necrosis of the capital femoral epiphysis (which occurs in 5 to 15% cases).
• Potential long-term complications include premature degenerative joint disease and low back pain.⁴

Document references

1. Godward S, Dezateux C; Surgery for congenital dislocation of the hip in the UK as a measure of outcome of screening. MRC Working Party on Congenital Dislocation of the Hip. Medical Research Council. Lancet. 1998 Apr 18;351(9110):1149-52. [abstract]
2. Harcke HT, Grissom LE; Infant hip sonography: current concepts. Semin Ultrasound CT MR. 1994 Aug;15(4):256-63. [abstract]
3. Macnicol MF; Results of a 25-year screening programme for neonatal hip instability. J Bone Joint Surg Br. 1990 Nov;72(6):1057-60. [abstract]
4. Sewell MD, Rosendahl K, Eastwood DM; Developmental dysplasia of the hip. BMJ. 2009 Nov 24;339:b4454. doi: 10.1136/bmj.b4454.
5. Kutlu A, Memik R, Mutlu M, et al; Congenital dislocation of the hip and its relation to swaddling used in Turkey. J Pediatr Orthop. 1992 Sep-Oct;12(5):598-602. [abstract]
6. Hoaglund FT, Healey JH; Osteoarthrosis and congenital dysplasia of the hip in family members of children who have congenital dysplasia of the hip. J Bone Joint Surg Am. 1990 Dec;72(10):1510-8. [abstract]
7. Woolacott NF, Puhan MA, Steurer J, et al; Ultrasonography in screening for developmental dysplasia of the hip in newborns: BMJ. 2005 Jun 18;330(7505):1413. Epub 2005 Jun 1. [abstract]
8. Barlow TG: Early diagnosis and treatment of congenital dislocation of the hip. J Bone Joint Surg Br 1962; 44: 292.
9. Kocher MS; Ultrasonographic screening for developmental dysplasia of the hip: an epidemiologic analysis (Part I). Am J Orthop. 2000 Dec;29(12):929-33. [abstract]
10. Storer SK, Skaggs DL; Developmental dysplasia of the hip. Am Fam Physician. 2006 Oct 15;74(8):1310-6. [abstract]
11. Dezateux C, Rosendahl K; Developmental dysplasia of the hip. Lancet. 2007 May 5;369(9572):1541-52. [abstract]

Internet and further reading

• Wheeless Textbook of Medicine; Developmental Dislocation of the Hip
• McCarthy J; Developmental dysplasia of the hip. eMedicine, February 2005.
• London Southbank University; X-ray of dislocated hip

Acknowledgements