Author(s): Matthew McLaughlin, MD, Denesh Ratnasingam, MD
Originally published: January 9, 2013 Last updated: December 22, 2020
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Disease/ Disorder

Definition

Congenital dysplasia of the hip, also referred to as developmental dysplasia of the hip (DDH), includes a spectrum of pathologies that includes mild acetabular dysplasia with a stable hip, dysplasias associated with hip subluxation, and hip dislocation. Presentation may vary and often is associated with a progressive course.1

Etiology

  • The etiology may be multifactorial including 1 or more hormonal, mechanical, or genetic factors.2,3
  • If subluxation or dislocation occurs and then persists, the femoral head becomes flattened and femoral anteversion occurs. The acetabulum becomes shallow and dysplastic.4
  • The final common pathway in the development of DDH is increased laxity of the hip capsule, in which the hip fails to maintain a stable, smooth articulation at the interface of the femoral head and the acetabulum causing increased likelihood of continued issues with subluxation or dislocation.2

Epidemiology including risk factors and primary prevention

DDH is found in approximately 1.3 per 1000 infants and children.1

Major risk factors are as follows2,3,5,6,7

  • White race among first born children.
  • Hip swaddling in adduction and extension.
  • Being a woman (women:men ratio is approximately 6:1).
  • Positive family history.
  • Ligamentous laxity.
  • Breech intrauterine positioning.
  • Conditions that lead to a tighter intrauterine space including oligohydramnios, high birthweight (>4000g), and first pregnancy.

Musculoskeletal deformities secondary to a crowding phenomenon in the womb may be seen in association with DDH, including metatarsus adductus in 4%8 of cases and torticollis in about 8% of cases.6,9

Patho-anatomy/physiology

Optimal femoral head and acetabular morphology depend intimately on a smooth, concentric reduction between the two with movement aiding in hip development. When the hip spends more time in subluxed or dislocated states, more opportunity exists for dysplastic changes to occur. Key points of pathoanatomy include2:

  • Fatty tissues in the depths of the hip, as well as hypertrophy of the ligamentum teres, preventing reduction.
  • The transverse acetabular ligament can also thicken, narrowing the opening of the acetabulum.
  • The iliopsoas tendon may shorten and become taut across the anterior hip, creating an hourglass shape to the hip capsule and limiting access of the femoral head to the acetabulum.
  • Over time, the displaced femoral head places pressure on the rim and labrum of the acetabulum, causing infolding and thickening of the labrum.

Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)

Early detection of DDH is critical because the pathology of DDH, along with subsequent clinical management, changes with time, as follows2,10:

  • Neonates: DDH will be asymptomatic and requires screening by specific clinical maneuvers (Ortolani test and Barlow test, as subsequently described in the Physical Examination section) and/or imaging.
  • Infants: After 2 to 3 months, soft tissues tighten and specific physical findings include limited hip abduction, thigh shortening (Galeazzi or Allis sign), and asymmetry of gluteal or thigh folds.
  • Ambulatory children: Often present after a leg-length discrepancy, limp, or waddling gait is noticed. These children will have a positive Trendelenburg sign, with a shortened femur on the affected side.
  • DDH is more commonly seen in the left hip (60%) but can often be found to be present bilaterally.5

Specific secondary or associated conditions and complications

Associated conditions and complications of DDH include avascular necrosis of the femoral head, redislocation, residual subluxation, acetabular dysplasia,6 persistent limp, premature development of degenerative arthritis of the hip, leg length discrepancy, lumbar lordosis, knee pain, scoliosis, and degenerative changes of the spine.3,4,6

If in utero hip dislocation occurs and the hips are not reducible on neonatal examination, chromosomal or neuromuscular conditions should be considered in the differential diagnosis. These conditions include myelomeningocele, arthrogryposis, and Ehlers-Danlos syndrome.5

Essentials of Assessment

History

A thorough review of the listed risk factors (i.e., positive family history, sex, breech positioning, conditions leading to a tighter intrauterine space) should help guide the examiner’s suspicion for DDH when screening.

Physical examination

Hip examination is recommended to be performed on all infants during routine clinical examinations. Hip instability in the neonate is classically screened via the Barlow and Ortolani tests, with the infant in a supine position2:

Barlow test, click of exit maneuver, which screens for dislocation of a non-displaced hip.7

  1. The examiner adducts the flexed hip and gently pushes the thigh posteriorly to try and dislocate the femoral head.
  2. The test is positive if the hip is felt to slide out of the acetabulum.

Ortolani test, click of entry maneuver, which screens for dislocation by trying to reduce a dislocated femoral head.7

  1. Grasping the child’s thigh between the thumb and index finger, the examiner lifts the greater trochanter with the 4th and 5th fingers while simultaneously abducting the hip.
  2. The test is positive when the femoral head slips into the hip socket with a fine clunk that should be palpable but not audible.

Note that clicks audible during Barlow and Ortolani maneuvers are usually benign and result from soft tissues snapping over bony prominences.1An estimated 1/100 newborns have evidence of some hip instability with a positive Ortolani or Barlow sign; however, a true dislocation is reported to be 1-15/1000 births.7

After 2 to 3 months of age, the soft tissues around the hip tighten, so the Barlow and Ortolani tests become unreliable. In infants at this stage of development, the examiner must consider other physical findings as follows.2,7,10

  1. Galeazzi (Allis) sign, which screens for shortening of the thigh.
    • With the infant supine, the examiner flexes the hips and knees, looking for asymmetry in the height of the knees.
    • This test is positive if one knee (when flexed) is lower than the other.
  2. Asymmetry of the gluteal or thigh folds.
  3. Limited hip abduction, especially if asymmetric (more difficult to detect if DDH is bilateral).
  4. Apparent limb shortening. A direct measurement of the ‘true’ limb length can be obtained from anterior superior iliac spine to the medial malleoli.

A walking child may present with abnormal gait signs, including any of the following2:

  1. Limp.
  2. Waddling gait.
  3. Hyperlordosis.
  4. Positive Trendelenburg sign.
  5. Asymmetry of pelvic alignment, as viewed from the frontal plane (use pelvic brim, anterior superior iliac spine, posterior superior iliac spine, and/or greater trochanters as landmarks).

Functional assessment

Manual serial hip examinations are recommended until a child ambulates. Subsequently, gait anomalies, including a Trendelenburg limp, waddling, and hyperlordosis, may be clues to the presence of DDH.

Imaging

Ultrasound is the diagnostic modality of choice, especially in asymptomatic infants, because it is superior to radiographs in evaluating cartilaginous structures of the femoral joint.2,3

  1. Placing the transducer on the greater trochanter allows visualization of the ilium, bony acetabulum, labrum, and femoral epiphysis, allowing visual confirmation of femoral head displacement, as well as pathologic malformation of bony and cartilaginous structures.2
  2. A dynamic technique, which assesses stability of the femoral head in the acetabulum as well as the static anatomy, is preferred.
  3. False-positives can occur in the early newborn period, because the acetabulum is immature and the joint has some temporary laxity (0-4 weeks of age).
  4. Favored for infants from 4 weeks to 4-6 months of age, which loses utility after 4-6 months.
  5. The Graf method of classification was developed in 1980 with severity ratings from type I (normal hip) to type IV (dislocated hip). A good quick reference for this classification is found at: http://radiopaedia.org/articles/graf-method-for-ultrasound-classification-of-developmental-dysplasia-of-the-hip
  6. Some centers utilize ultrasonography in patients with a positive Ortolani sign and its used progressively to monitor subluxation or dislocated hip being treated in a Pavlik harness

Radiographs (anteroposterior [AP] view) are recommended after femoral head ossification (4-6 months) occurs.2

  1. Lateral femoral head migration is measured by the intersection of the Hilgenreiner line (horizontal through the triradiate cartilage) and the Perkins line (vertical from the lateral acetabulum).
  2. The AP view is interpreted via the acetabular index (AI), which measures the slope of the ossified acetabular roof. AI >30 degrees is abnormal.
  3. A broken Shenton line (a curved line drawn from the medial femoral neck to the lower border of the superior pubic ramus) is indicative of hip subluxation or dislocation.

Computed tomography is helpful for follow-up as opposed to initial diagnosis.11

Magnetic resonance imaging is used to help evaluate for avascular necrosis in patients with progressive DDH.11

Hip arthrogram is primarily done in the operating room by an orthopedic surgeon to evaluate the joint during and/or after closed reduction of the hip.11

Arthrography, computed tomography and magnetic resonance imaging may be beneficial and older infants and children when early diagnostic imaging is difficult to assess and make the diagnosis.6

Rehabilitation Management and Treatments

Available or current treatment guidelines

Clinical practice guidelines on early detection and management have been published by the American Academy of Pediatrics in 2000.12 This report includes a clinical algorithm for screening and recommended actions in the presence of risk factors.

At different disease stages

All newborn infants should be evaluated at birth. The primary care practitioner bears the responsibility for initial assessment and newborn screening. Referral to an orthopedist should be made if a positive Ortolani or Barlow sign is detected. If the newborn screening exam is equivocal or negative in the presence of risk factors, periodic follow-up exams are recommended, as described in the clinical practice guidelines published by the American Academy of Pediatrics.5,12 Children with equivocal physical exam findings or increased risk factors should undergo imaging.

Triple diapering is a common practice in newborns, which lacks clinical evidence for effectiveness in treatment and may delay appropriate referral to orthopedics when clearly dislocated.3

For patients <1 year old with a negative Ortolani sign, traction for three to six weeks is an option with imaging and consideration for possible closed reduction with dynamic arthrogram. If successful with less than 6 mm gap, the patient should be in a spica case for 2-3 months. If the procedure failed with a gap greater than 6 mm, an open reduction can be attempted.13

For patients <1 year old with an Ortolani sign, the Pavlik harness is indicated for children with evidence of hip dysplasia and an abnormal ultrasound or persistent subluxation.5 Due to growth, adjustments of the straps every 2 weeks are required to account for the growth of infants. Failure to make these adjustments can result in additional hip pathology or dislocating a previously reduced hip.5 Weaning from the Pavlik harness over a 3 to 4 week period may start once the ultrasound findings become normal and serial clinical examinations demonstrate stability at the hips.5 After 6 months of age, the Pavlik harness is replaced by a hip abduction orthoses – like the Ilfeld orthosis –  to manage persistent hip instability. If follow-up physical examinations and/or ultrasounds do not show that the hip is reduced after 3 to 4 weeks, the harness should be abandoned and orthopedic consultation obtained. Pavlik harness has 95% rate of treatment in Ortolani-positive hips and 85% rate of treatment in reduction of subluxed or dislocated hip. Complications of using the Pavlik harness are usually iatrogenic with prolonged excessive hip flexion, induction of a femoral nerve compression neuropathy has resolves with removal of harness and compression, and cartilaginous femoral head and proximal femoral physeal pate damage from forced abduction with failure of reduction in a complete dislocation. Other devices like von Rosen splint and Frejka pillow are used but the Pavlik harness continues to be the most commonly used device in treatment of DDH.7

Closed reduction of the hips, followed by hip spica casting, is the preferred method of treatment for persistent dislocated hips in children under 18 months of age. Casts are typically used for 3 to 4 months, with cast changes every 6 weeks.5 If a child receives a spica cast, specialized car seating systems may need to be ordered such as the Hippo Car Seat as they spica cast may prohibit safe car transport while wearing.

If there is failure of closed treatment in patients 6 months to 2 years old, open reduction is indication to obtain and maintain reduction.7 Open hip reduction with or without femoral shortening osteotomy usually occurs for children greater than 2 years old.14

Internal reduction is required when the Pavlik harness and/or closed reduction is ineffective. This most commonly occurs after the child is 18 months of age. Surgical interventions may include percutaneous adductor tenotomy, psoas tenotomy, femoral osteotomy, and pericapsular osteotomy.3,4

Failure to adequately achieve reduction in the older child may lead to more chronic medical issues requiring continued treatment. Pain, osteoarthritis, and gait deviations may occur if the hip is not properly reduced. Development of acetabular dysplasia requires acetabular or femoral osteotomies to increase the coverage of femoral head acting on the acetabular side. While savage osteotomies remain controversial in unstable hips, reorientation osteotomies increase lateral and anterior coverage of the femoral head. Regardless, acetabuloplasties provide a higher degree of correction compared to reorientation osteotomies.15 Long-term complications can arise, such as a need for earlier total hip arthroplasty in the young adult period.16 Postsurgical rehabilitation should include a physical therapy program focusing on stretching of tight hip and leg muscles, positioning, weight bearing, and appropriate orthoses.17

Coordination of care

Once DDH is identified, consultation with an orthopedic surgeon is required. On occasion, pediatric rehabilitation physicians may be asked to provide advice on positioning and splinting. Because undiagnosed or mismanaged DDH may lead to undesired consequences, communication between the primary care provider, orthopedist, and pediatric physical medicine and rehabilitation is essential. Patients and orthotists need communication regarding who is the primary physician managing the orthotic. If pediatric therapists are involved in helping the family use the hip positioning devices, it is important the therapists provide feedback to the physician directing the treatment program.

Patient & family education

Helping educate the family about the process of care necessary to screen for DDH can be of great value. They could be more likely to bring their child to the primary care provider for routine well-child visits (where serial hip exams can be performed), because a DDH diagnosis can often be missed.3,4,11

Cutting Edge/ Emerging and Unique Concepts and Practice

Issues Related to Care of Hip Dysplasia with Conservative Treatment vs Surgical Options

If conservative treatment fails, the reason for pushing toward a surgical management is usually secondary to late diagnoses or presentation of hip dysplasia. Open reduction has been a selected surgical option occurring more frequently in those presenting with late dysplasia. Reasons for late hip dysplasia presentation have been associated in patients who were not appropriately screened earlier in care either at newborn screening or with a history, physical exam, or US methods. 18

In those requiring a surgical approach, the use of hip arthroscopy is common in the management of femoroacetabular impingement and labral tears; however, there is heterogeneity in management approach to doing a hip arthroscopy in patients with hip dysplasia secondary to variable outcomes.19

Comparing results of early vs delayed surgery for those with hip dysplasia, those with delayed surgery were found to have complications including decreased range of motion and a limping gait secondary to hip pathology resulting in an abnormal gait cycle.20

Gaps in the Evidence- Based Knowledge

There is significant medical literature evidence that though patients with dysplastic hips improve after hip arthroscopy, the re-operation rate is increased the total hip arthroplasty rate is also increased compared to the general hip arthroscopy population.19 There is no significant evidence that early vs delayed surgery results in higher incidence of recurrent surgeries.21

Specific causes have been felt to be secondary to infection like a septic joint or delay in surgery with a chronic dislocation after reconstruction; however, there is limited medical literature from a meta-analysis or systematic review on this topic.

References

  1. Sewell MD, Rosendahl K, Eastwood DM. Developmental dysplasia of the hip. BMJ. 2009; 339:1242-1248.
  2. Sankar, WN, Horn DH, Wells L, Dormans JP. The hip. In: Kliegman RM, Stanton BF, St. Geme JW III, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier; 2011:2355-2365.
  3. Moberg-Wolff, E. Hip: developmental hip dysplasia. In: Nelson MR, ed. Pediatrics: Rehabilitation Medicine Quick Reference. New York, NY: Demos Medical; 2011:116-117.4.
  4. Aronsson D, Goldberg M, Kling T, Roy D. Developmental dysplasia of the hip. Pediatrics. Aug 1994; 94 (2).
  5. Alexander MA, Matthews DJ, eds. Pediatric Rehabilitation: Principles and Practice. 4th ed. New York, NY: Demos Medical; 2010:386-389.
  6. Behrman, R.E., Kliegman, R.M., and Jenson H.B. Nelson Textbook of Pediatrics. 16 ed. 2000. Ch 684: The Hip: 648.1 Developmental Dysplasia of the Hip; 2077-2079.
  7. Weinstein, S.L. Lovell and Winter’s Pediatric Orthopedics. 7th ed. 2014. Chapter 23: Developmental Dysplasia of the Hip. 983-1830.
  8. Paton RW, Choudry Q. Neonatal foot deformities and their relationship to developmental dysplasia of the hip. J Bone Joint Surg Br. 2009; 91:655-658.
  9. Walsh JJ, Morrissy RT. Torticollis and hip dislocation. J Pediatr Orthop. 1998; 18:219-221.
  10. Nemeth B, Narotam V. Developmental Dysplasia of the Hip. Pediatrics in Review. Dec 2012, 33(12). 553-561.
  11. Rossi, R, Alexander, M, Cuccurullo, SJ. Pediatric rehabilitation. In: Cuccurullo SJ, ed. Physical Medicine and Rehabilitation Board Review. 2nd ed. New York, NY: Demos Medical; 2010:713-808.
  12. Karmazyn, BK, Gunderman RB, Coley BD, et al. ACR Appropriateness Criteria on developmental dysplasia of the hip-child. J Am Coll Radiol. 2009; 6:551-557.
  13. Roberts, J.M. Fitzgerald, Haufer, and Malani Orthopaedics. Section 9; Chapter 16; Development dysplasia of the hip: diagnosis and treatment of the non-ambulator. 2002. 1328-1393.
  14. Yang, S., Zusman, N., Lieberman, E., et. al. Developmental Dysplasia of the Hip. Pediatrics. 2019;143(1): e20181147
  15. Vaquero-Picado, A., Gonzalez-Moran G, Garay, E.G., et. al. Developmental dysplasia of the hip: update of management. Paediatircs EOR;2019; 4; 548-556.
  16. Herring JA. Tachdijan’s Pediatric Orthopedics. Philadelphia, PA: Elsevier Sanders; 2014.
  17. Driscoll SW, Skinner J. Musculoskeletal complications of neuromuscular disease in children. Phys Med Rehabil Clin N Am. 2008; 19:163-194.
  18. Lee, WC., Gera, SK., Mahadev A. Developmental dysplasia of the hip: why are we still operating on them? A plea for institutional newborn clinical screening. Singapore Med J. 2019; 60(3): 150-153. DOI 10.11622.2018064
  19. Yeung, M., Kowalczuk, M., Simunovic, N., Ayeni, OR. Hip arthroscopy in the setting of hip dysplasia: a systematic review. Bone Joint Res. 2016; 5 (6): 225-231. DOI: 10.1302/2046-3758.56.2000533.
  20. Alnamshan MK., Jawadi AH., Alshoaibi YA., et. al. Outcome of delayed surgery in developmental hip dysplasia in a teritiary care setting. Egyptian J of Hos Med. 2018; 73(4): 6446-6451
  21. Willemsen, K., Doelman CJ., Sam ASY., et. al. Long-term outcomes of the hip shelf arthroplasty in adolescents and adults with residual hip dysplasia: a systematic review. Acta Orthopaedica. 2020; 91 (4): 383-389. DOI: 10.1080/17453674.2020.1747210.

Original Version of the Topic:

Frank S. Pidcock, MD, Andrew H. Gordon, MD, PhD. Congenital hip dysplasia. Published 1/9/2013

Previous Revision(s) of the Topic:

Matthew McLaughlin, MD. Congenital hip dysplasia. Published 8/19/2016

Author Disclosure

Matthew McLaughlin, MD
National Institute of Health (NICHD), Grant, Principal Investigator

Denesh Ratnasingam, MD
Nothing to Disclose