Developmental dysplasia of the hip (DDH) is the preferred term for the disease previously referred to as congenital dislocation of the hip since it recognises that presentation can follow a normal examination of the hips in the newborn period. Some facts:
- Highest risk in breech presentation and positive family history.
- Prevalence is higher in firstborn and females.
- DDH refers to a spectrum of disorders of hip instability producing subluxation or dislocation and imaging features of poor acetabular development.
- Early detection is vital. If DDH is left untreated the hip joint develops abnormally and surgical reduction is required. By contrast, early conservative management with splinting (for example, Denis-Browne splint) or Pavlik harness allows the hip joint to develop normally and avoids the need for surgery in most cases.
Pathogenic factors for DDH
Developmental hip dysplasia may be caused by:
- abnormal rotation of the developing hip during the first trimester
- neuromuscular disease, especially in the second trimester
- abnormal mechanical forces such as oligohydramnios, breech presentation (particularly frank breech), in the third trimester
- female infants (who are more susceptible to the maternal hormone relaxin)
- postnatal mechanical forces associated with swaddling or wrapping (African infants strapped to their mothers' backs with hips abducted have a very low incidence of DDH).
- All newborn infants should have the Ortolani and Barlow tests performed by a trained examiner as part of the routine newborn examination.
- Unfortunately, infants who are unwell after birth and who require admission to neonatal intensive or special care units often have this important part of their newborn examination omitted.
- It must always be documented that the examination has been performed both in the infant's medical record and child health record.
- Infants in whom the examiner is uncertain of the findings should be re-examined by a more experienced clinician prior to discharge.
- Inexperienced examiners who are unsure whether what they are feeling is a 'click' (which can be a common finding caused by ligaments moving over bony prominences) or a 'clunk' are advised to enlist expert help.
- Infants in whom either test is positive should be assessed by an experienced clinician prior to discharge and fitted with a splint/harness. In the absence of an experienced clinician at your health service, referral to an orthopaedic specialist is desirable. Ultrasound can help confirm the clinical signs and assist in monitoring the response to treatment.
- The longer the hip is left in abnormal position the more the anatomy changes, developing abnormalities of the proximal femur and acetabulum. After 18 months, both bones may need surgical correction to provide joint congruity and stability.
- Since DDH can develop over time, all infants (both high and low risk) with normal newborn examinations should have their hips regularly re-examined during the first year of life
High-risk infants may need ultrasound
High-risk infants in whom examination is normal should have ultrasonography performed at about six to 12 weeks after birth or at six to eight weeks corrected age if born prematurely.
High risk infants include:
- family history of DDH (one or more first-degree relative or two or more second-degree relatives)
- breech presentation
- neuromuscular disease such as arthrogryposis or spina bifida
- low liquor volume
- birthweight over 5 kg.
There is no 'gold standard' diagnostic test for DDH. The Ortolani and Barlow tests are widely used for screening.
- The Ortolani test detects a dislocated hip reducing during the examination.
- The Barlow test detects a hip dislocating or subluxing during the examination.
- Both tests will detect an unstable hip but will not detect a dislocated irreducible hip. However, a dislocated irreducible hip will have a reduced range of movement. In a neonate, both hips should be able to be abducted so the lateral surface of the knees can make contact with the surface the back is on.
- A positive Ortolani or Barlow test is one in which a distinctive 'clunk' is felt. 'Clicks' are often felt while performing these tests, causing considerable confusion but are not predictive of DDH.
- Additional signs such as a discrepancy in leg length, a widened perineum on the affected side, buttock flattening and asymmetrical thigh skin folds may be present. None of these signs is particularly sensitive or specific. Asymmetric skin folds are found in 25 per cent of normal babies; on its own this is not an important clinical finding.
- Heath professionals who wish to learn the tests should:
- consult an authoritative text or complete the online education module provided by the Royal Children's Hospital Melbourne
- be shown how to perform both tests by an expert
- practice the tests on the 'Baby Hippy' manikin
- practice the tests on many infants to perfect their technique.
X-rays not recommended for DDH
X-rays are unhelpful in assessment at birth as the femoral head is cartilaginous until six months of age.
Areas of uncertainty in clinical practice
- Ultrasound examination of the hips has been advocated by some as the most effective method of screening for DDH. Although very sensitive as a screening tool, it has low specificity, is expensive and is operator dependent. For this reason, the American Academy of Paediatrics considers it an adjunct to clinical examination.
- There is no evidence to support the use of double or triple nappies until definitive treatment is instituted.
- Developmental Dysplasia of the Hip, online module from the Royal Children's Hospital Melbourne by Leo Donnan and Richard Angliss. This provides a comprehensive overview of the condition with emphasis on examination skills and detection.
- Safe wrapping for Developmenta Dysplasia of the Hips (DDH)
- Brace treatment for Developmental Dysplasia of the Hip (DDH)
- AAP Clinical Practice Guideline: Early Detection of Developmental Dysplasia of the Hip
- RPA Newborn Care
- BMJ - Developmental dysplasia of the hip
- American Academy of Pediatrics. Clinical Practice guidelines: Early detection of developmental dysplasia of the hip. Pediatrics 2000; 105:896-905.
- Griffin PP, Robertson WW Jr. Orthopedics. In: Avery GB, Fletcher MA, MacDonald MG, editors. Neonatology: Pathophysiology and management of the newborn. Philadelphia: Lippincott, Williams & Wilkins, 1999:1270.
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First published: May 2017
Last web update: October 2018
Review by: May 2020
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Page last updated: 21 Nov 2018