DEVELOPMENTAL DYSPLASIA OF THE HIP
DDH | Ortolani | Barlow | Pavlik Harness | Pelvic Osteotomy
BY AGE
Critical Must-Knows
- Ortolani reduces a dislocated hip
- Barlow dislocates an unstable hip
- Pavlik harness for under 6 months
- Open reduction if Pavlik fails or late diagnosis
- Acetabular dysplasia needs osteotomy
Examiner's Pearls
- "Risk factors: breech, female, first-born, family history
- "Graf ultrasound classification
- "Pavlik success 90-95% if started under 6 weeks
- "Avascular necrosis is worst complication
Critical DDH Concepts
Ortolani Test
Reduces a dislocated hip. Abduct hip with anterior pressure on greater trochanter. Clunk = hip reducing into acetabulum. Positive = hip was dislocated.
Barlow Test
Dislocates an unstable hip. Adduct hip with posterior pressure. Clunk = hip dislocating posteriorly. Positive = hip is unstable/dislocatable.
Pavlik Harness
First-line for under 6 months. Maintains hip in flexion and abduction. 90-95% success if started early. Monitor for AVN.
AVN Risk
Most serious complication. Caused by forced abduction or reduction. Maintain safe zone (avoid excessive abduction).
At a Glance
DDH At a Glance
| Feature | Key Points |
|---|---|
| Definition | Spectrum of hip instability from dysplasia to dislocation |
| Risk factors | Breech, Female, First-born, Family history (BFFF) |
| Key tests | Ortolani (reduces) and Barlow (dislocates) - look for clunk, not click |
| First-line treatment | Pavlik harness under 6 months (90-95% success if started early) |
| Critical complication | AVN from forced abduction - maintain safe zone |
| Late presentation | Requires open reduction + osteotomy with higher complication risk |
Ortolani vs Barlow
| Test | What It Does | Positive Finding |
|---|---|---|
| Ortolani | Reduces dislocated hip | Clunk = hip reducing into acetabulum |
| Barlow | Dislocates unstable hip | Clunk = hip dislocating out |
BFFFDDH Risk Factors
Memory Hook:BFFF - Breech First-born Female with Family history!
ORIRemember Ortolani vs Barlow
Memory Hook:Ortolani Reduces In - brings hip back in!
FLEX ABDPavlik Harness Position
Memory Hook:FLEX ABD - position for Pavlik success!
Overview and Epidemiology
Why Left Side More Common
Left hip is against mother's spine in utero. This position limits abduction and promotes dysplasia. Left side 60%, Right 20%, Bilateral 20%.
Anatomy and Pathophysiology
Hip Joint Development
In utero:
- Femoral head and acetabulum develop together
- Movement stimulates development
- Restricted movement causes dysplasia
Acetabular development:
- Triradiate cartilage contributes to growth
- Labrum deepens socket
- Shape influenced by femoral head position
Normal development requires hip in reduced position.
Pathology and Natural History
Acetabular Changes
- Primary Dysplasia: Shallow, saucer-shaped acetabulum with poor anterior and lateral coverage.
- Secondary Changes: In dislocation, the acetabulum fills with fibrofatty tissue (pulvinar).
- False Acetabulum: In high dislocation, a pseudo-acetabulum forms on the ilium, while the true acetabulum becomes shallow.
Dysplasia proceeds to dislocation if untreated.
Classification
Severity Classification
Dysplastic: Abnormal acetabulum but hip located - shallow socket with inadequate coverage Subluxed: Partial contact between femoral head and acetabulum - hip partially displaced Dislocated: No contact between femoral head and acetabulum - complete displacement
Teratologic DDH: Early in utero dislocation with severe soft tissue contractures (associated with syndromes like arthrogryposis). More resistant to treatment.
Severity guides treatment urgency and prognosis.
Clinical Assessment
Newborn Screening
- Ortolani test (abduct, lift)
- Barlow test (adduct, push posteriorly)
- Assess hip stability
- Look for limb length discrepancy
- Asymmetric skin folds (less reliable)
All newborns should be screened.
Older Infant/Child
- Limited hip abduction (most reliable)
- Galeazzi sign (limb length)
- Asymmetric gluteal folds
- Trendelenburg gait (walking age)
- Late presentation more challenging
Limited abduction is key sign in older infant.
Click vs Clunk
Soft clicks are common and usually benign. A clunk (palpable hip movement) is significant. DDH is a clunk, not a click.
Investigations
Hip Ultrasound
Timing:
- Screening at 4-6 weeks if risk factors
- Diagnostic if clinical suspicion
Graf Classification:
- Type I: Normal (alpha greater than 60)
- Type II: Immature/dysplastic
- Type III: Dislocated, labrum everted
- Type IV: Dislocated, labrum inverted
Alpha angle measures acetabular coverage.
Management Algorithm
Pavlik Harness
First-line treatment for newborn DDH:
- Maintains hip in flexion (100-110 degrees) and abduction (50-70 degrees)
- Full-time wear initially (23 hours/day)
- Weekly follow-up with ultrasound to confirm reduction
Success factors:
- Age at initiation: 90-95% if started under 6 weeks, decreases to 50% after 3 months
- Type of dysplasia: Better for Graf II-III, poorer for Graf IV (inverted labrum)
- Bilateral cases may need longer treatment
Duration: Until stable on ultrasound, typically 6-12 weeks full-time, then part-time weaning
Complications to monitor:
- Femoral nerve palsy (excessive flexion)
- Inferior epiphyseal ischemia (AVN from forced abduction)
- Skin irritation and pressure sores
Discontinue if: No reduction after 3-4 weeks (Pavlik disease risk - inverted labrum prevents reduction and worsens with continued harness use).
Surgical Techniques
Approaches
Medial approach (under 12 months):
- Avoids capsulorrhaphy
- Less dissection
- Appropriate for younger infants
Anterior (Smith-Petersen) approach:
- Better visualization
- Allows capsulorrhaphy
- For older children
Clear obstacles to reduction: psoas, transverse ligament, ligamentum teres.
Complications
| Complication | Incidence | Prevention/Management |
|---|---|---|
| AVN | 0-5% Pavlik, higher with surgery | Avoid forced abduction, safe zone |
| Residual dysplasia | 10-20% | Osteotomy at appropriate age |
| Redislocation | Variable | Adequate immobilization |
| Femoral nerve palsy (Pavlik) | Rare | Proper harness application |
AVN Prevention
Avoid forced abduction. Safe zone = angle of reduction to redislocation. Keep hip in middle of safe zone. Excessive abduction compresses lateral epiphyseal vessels.
Postoperative Care
DDH Recovery Timeline
Hip spica cast for 6-12 weeks. Position: abduction and flexion within safe zone. Cast changes as needed.
Spica cast 6-12 weeks post-reduction. Cast changes for growth. X-ray to confirm reduction maintained.
Transition to abduction brace for 2-3 months. Night-time wear. Promotes hip stability.
Regular X-rays to assess acetabular development. Monitor for residual dysplasia until skeletal maturity. May need future osteotomy.
Follow-up Key
Monitor acetabular index until skeletal maturity. Residual dysplasia may require pelvic osteotomy at appropriate age (Salter 18mo-6yrs, PAO adolescent).
Outcomes
Prognostic Factors
Better outcomes: Early diagnosis (under 6 weeks), Pavlik treatment, concentric reduction.
Worse outcomes: Late diagnosis, open reduction, AVN, residual dysplasia.
Treatment Outcomes by Age
- Diagnosis under 6 weeks: 90-95% success with Pavlik harness alone
- Diagnosis 3-6 months: 70-80% success with Pavlik; may need closed reduction
- Diagnosis 6-12 months: Often requires closed reduction + spica
- Diagnosis 12-18 months: Usually needs open reduction + spica
- Diagnosis over 18 months: Open reduction + pelvic osteotomy + femoral osteotomy
Long-Term Considerations
Children treated for DDH require follow-up until skeletal maturity:
- Acetabular development: Monitor acetabular index; residual dysplasia may need pelvic osteotomy
- Avascular necrosis: May not manifest for 6-12 months post-treatment
- Hip function: Most treated hips function normally if reduction achieved early
- Osteoarthritis risk: Higher with residual dysplasia or AVN; may need THR in adulthood
Avascular Necrosis Risk
AVN is the most feared complication with rates varying by treatment:
- Pavlik harness: 0-5% (with proper technique)
- Closed reduction: 5-15%
- Open reduction: 10-25%
- Risk factors: Excessive abduction, prolonged immobilization, older age at treatment
Prevention of Avascular Necrosis
Avoiding AVN requires adherence to established principles:
- Maintain safe zone of abduction (Ramsey criteria)
- Avoid forced or excessive abduction during treatment
- Consider femoral shortening in older children to reduce reduction pressure
- Monitor closely during treatment for signs of vascular compromise
Evidence Base
Pavlik Harness Outcomes
- 90-95% success under 6 weeks
- Lower success if started later
- AVN 0-5% with proper technique
- Standard first-line treatment
DDH Screening Programs
- Clinical screening reduces late diagnosis by 70%
- Selective US for at-risk reduces late cases by 50%
- Universal US screening does not improve outcomes vs selective
- Combined clinical + selective US is optimal
Long-term Outcomes of Pavlik
- Excellent long-term function if reduced
- Low rate of avascular necrosis
- Residual dysplasia may require later surgery
- Compliance is key factor
Avascular Necrosis Risk Factors
- AVN rates 0-5% for Pavlik, 5-15% for closed reduction, 10-25% for open
- Higher AVN with forced abduction and extreme positions
- Femoral shortening reduces AVN in late cases
- Safe zone concept validated
Salter Innominate Osteotomy Outcomes
- 85-95% good/excellent results at 25+ year follow-up
- Better outcomes if normal concentric reduction achieved
- Residual dysplasia correlates with early OA
- Femoral osteotomy improves outcomes when indicated
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: Newborn DDH
"A newborn girl born breech has a positive Ortolani test on the left hip. What is your diagnosis and management?"
Scenario 2: Late Presenting DDH
"An 18-month-old girl presents with a limp. She has limited left hip abduction and a positive Galeazzi sign. X-ray shows a dislocated left hip with a shallow acetabulum. How do you manage this?"
Scenario 3: Residual Dysplasia
"A 5-year-old female is seen for follow-up. She was treated with a Pavlik harness as an infant. She is asymptomatic. X-ray shows the Acetabular Index is 30 degrees (normal less than 20). What is your management?"
Scenario 4: Pavlik Harness Failure
"A 4-month-old infant with DDH has been in a Pavlik harness for 4 weeks. Repeat ultrasound shows the hip remains dislocated (Graf Type IV). What is your management?"
MCQ Practice Points
Ortolani Test
Q: What does a positive Ortolani test indicate? A: The hip is dislocated but reducible. Abduction with anterior pressure reduces the femoral head into the acetabulum.
Barlow Test
Q: What does a positive Barlow test indicate? A: The hip is unstable and can be dislocated. Adduction with posterior pressure causes the hip to dislocate.
Treatment Question
Q: What is first-line treatment for DDH under 6 months? A: Pavlik harness. 90-95% success if started under 6 weeks.
AVN Risk
Q: What increases AVN risk in DDH treatment? A: Forced abduction. Compresses lateral epiphyseal vessels. Keep within safe zone.
Graf Type IV
Q: What is the significance of Graf Type IV? A: Labrum inverted into acetabulum. Poor prognosis with Pavlik harness - often requires open reduction to clear the inverted limbus.
Residual Dysplasia
Q: A 5-year-old has acetabular index greater than 25 degrees. What surgery is indicated? A: Pelvic osteotomy (Salter or Pemberton). Redirects or reshapes acetabulum to improve coverage and prevent early OA.
Australian Context
DDH Screening in Australia:
- Clinical screening of all newborns by midwives and pediatricians (Ortolani, Barlow)
- Selective ultrasound screening for at-risk infants (breech, family history, first-born female)
- Follow-up screening at 6-week postnatal check
- Australian Paediatric Surveillance Unit monitors late-presenting DDH
Indigenous Health Considerations:
- Similar incidence to general population
- Late diagnosis more common in remote and regional areas due to access issues
- Telehealth consultations increasingly used for specialist follow-up
- Cultural considerations for treatment compliance and family support
Health System Considerations:
Regional/Remote Access
Limited access to pediatric orthopaedic specialists outside capital cities. Telehealth for initial consultations and follow-up. Royal Flying Doctor Service may transport for surgical care. Pavlik harness management requires local GP/nursing support. Late diagnosis rates higher in remote areas.
Healthcare Funding
Hip ultrasound covered under Medicare. Pavlik harness covered through state orthotics programs. Pediatric orthopaedic surgery covered in public hospitals. Hip spica casting covered as inpatient admission. Long-term follow-up covered through pediatric services.
Australian DDH Guidelines (POSNA/RACS adapted):
- Clinical screening mandatory for all newborns
- Selective US for risk factors (breech, family history, clinical concern)
- Universal US screening not currently recommended (cost-effectiveness)
- Tertiary pediatric orthopaedic centers in each state capital
Referral Pathways:
- GP/midwife identifies clinical concern or risk factors
- Ultrasound arranged at 4-6 weeks
- Abnormal US or clinical concern → pediatric orthopaedic referral
- Urgent referral for dislocated hip (Ortolani positive)
Australian DDH Key Point
Australia follows selective US screening for at-risk infants, not universal screening. Risk factors: breech presentation, family history, first-born female. Clinical screening remains the primary detection method for all newborns.
DEVELOPMENTAL DYSPLASIA OF THE HIP
High-Yield Exam Summary
Risk Factors (BFFF)
- •Breech presentation
- •Female (4:1)
- •First-born
- •Family history
- •Oligohydramnios
- •Torticollis/foot deformity
Examination
- •Ortolani: reduces dislocated hip
- •Barlow: dislocates unstable hip
- •Clunk (not click) is significant
- •Limited abduction (older infant)
- •Galeazzi sign (limb length)
- •Trendelenburg gait (walking age)
Imaging
- •US under 4-6 months (Graf)
- •X-ray after 4-6 months
- •Alpha angle measures coverage
- •Shenton line disrupted
- •Acetabular index elevated
Treatment by Age
- •0-6 months: Pavlik harness
- •6-18 months: closed/open reduction
- •Walking age: open + osteotomy
- •Stop Pavlik if no reduction by 3-4 weeks
- •Femoral shortening for late cases
Pavlik Harness
- •Flexion 100-110 degrees
- •Abduction 50-70 degrees
- •90-95% success if under 6 weeks
- •Full-time wear initially
- •Weekly US follow-up
Complications
- •AVN (avoid forced abduction)
- •Residual dysplasia
- •Redislocation
- •Pavlik disease (late reduction)
- •Femoral nerve palsy