Developmental Dysplasia of the Hip (DDH)
Spectrum of hip instability ranging from mild acetabular dysplasia to frank dislocation in infants.
Also known as: DDH, developmental dysplasia of the hip, congenital hip dysplasia, CHD
Overview
A spectrum of disorders involving abnormal development of the hip joint in which the femoral head and acetabulum fail to form a stable concentric relationship. Ranges from mild acetabular dysplasia to subluxation to frank dislocation.
Epidemiology
Incidence of frank dislocation approximately 1 in 1,000 live births; milder hip instability detectable in 1-3 percent of newborns. Female-to-male ratio approximately 4-6:1. Left hip more commonly involved than right; bilateral in 20 percent.
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Risk factors
- Female sex
- Breech presentation, especially frank breech (5-10x risk)
- Family history of DDH in a first-degree relative
- Firstborn (tighter uterine packaging)
- Oligohydramnios
- Postnatal swaddling with hips extended and adducted
- Associated conditions: torticollis, metatarsus adductus, congenital muscular conditions
Pathophysiology
Combination of ligamentous laxity (maternal hormonal influence), abnormal mechanical forces in utero, and acetabular morphology. A shallow acetabulum cannot retain the femoral head, allowing subluxation or dislocation. Persistent malposition leads to remodeling abnormalities — false acetabulum, hypertrophied labrum (limbus), and tight psoas, all of which become barriers to reduction.
Clinical presentation
Symptoms
- Often asymptomatic in newborns; identified on screening
- Older infant (>3 months): asymmetric thigh or gluteal skin folds, limited hip abduction
- Toddler: delayed walking, Trendelenburg gait, leg length discrepancy
- Bilateral dislocation may present with waddling gait and exaggerated lumbar lordosis
Signs / physical exam
- Ortolani maneuver (reduction): hip flexed and gently abducted with anterior pressure on the greater trochanter — palpable clunk as femoral head reduces into acetabulum
- Barlow maneuver (dislocation): hip flexed and adducted with posterior pressure on the knee — palpable clunk as femoral head exits the acetabulum
- Galeazzi sign: with hips and knees flexed, knees are at unequal heights (the dislocated side appears shorter)
- Limited hip abduction in older infants
- Asymmetric thigh and inguinal skin folds
Classic findings
Female infant with a positive Ortolani clunk on examination, or an older infant with asymmetric thigh folds, limited abduction, and a positive Galeazzi sign.
Differential diagnosis
- Coxa vara congenita — Decreased femoral neck-shaft angle; identified later in childhood with limp
- Proximal femoral focal deficiency — Major deficiency of the proximal femur on imaging; obvious limb length discrepancy
- Neuromuscular hip dislocation (cerebral palsy, spina bifida) — Identified in the setting of known neuromuscular disease, usually progressive
- Septic arthritis of the hip — Acute onset, fever, refusal to move limb, elevated inflammatory markers
- Transient hip click without instability — High-pitched click without instability on Ortolani/Barlow; usually benign
Diagnostic workup
Diagnostic criteria
Graf classification by ultrasound uses alpha (bony roof) and beta (cartilaginous roof) angles. Type I — alpha ≥60 degrees, normal; Type IIa — physiologic immaturity <3 months, alpha 50-59; Type IIb — pathologic at >3 months; Type III — subluxated; Type IV — dislocated. On radiographs, the femoral head should lie within the lower inner quadrant of Hilgenreiner and Perkins lines.
Labs
- None required
Imaging
- Ultrasound of the hips — gold standard before 4-6 months of age (femoral head is not yet ossified)
- Plain radiographs (AP pelvis) — preferred after 4-6 months when the ossific nucleus is visible
- MRI or CT post-reduction to confirm concentric reduction
- AAP recommends ultrasound at 6 weeks for high-risk infants (breech delivery, family history); routine universal ultrasound is not endorsed
Diagnostic algorithm
| Age | Best Examination Finding | Preferred Imaging | Initial Treatment |
|---|---|---|---|
| Newborn-3 mo | Ortolani / Barlow clunk | Ultrasound at 6 wk if high risk | Pavlik harness |
| 3-6 mo | Limited abduction, asymmetric folds | Ultrasound | Pavlik harness |
| 6-18 mo | Galeazzi sign, limited abduction | AP pelvis radiograph | Closed reduction and spica |
| >18 mo | Limp, Trendelenburg gait | AP pelvis radiograph | Open reduction ± osteotomy |
Treatment
First-line
- Pavlik harness for infants <6 months — maintains flexion 90-100 degrees and abduction to promote concentric reduction; worn 23 hours per day with weekly follow-up
- Success rate of Pavlik harness is 80-95 percent for reducible dislocations in young infants
- Avoid forced abduction (femoral nerve palsy or AVN from over-aggressive positioning)
Second-line / adjunct
- Closed reduction under anesthesia with arthrogram and spica casting for failed Pavlik or older infants (6-18 months)
- Open reduction with capsulorrhaphy and possible femoral and/or pelvic osteotomy for older children or failed closed reduction
- Salvage osteotomy (Salter, Pemberton, periacetabular) for residual dysplasia in older children and adolescents
Complications
- Avascular necrosis of the femoral head (most feared complication of treatment, especially with forced abduction)
- Redislocation after reduction
- Residual acetabular dysplasia with progressive subluxation
- Early hip osteoarthritis in adulthood (dysplasia is a leading cause of total hip arthroplasty in young adults)
- Limb length discrepancy
PANCE pearls
- Ortolani and Barlow maneuvers are most reliable in the first weeks to months of life; after 3 months, the dislocated hip becomes harder to reduce and limited abduction becomes the dominant finding.
- Ultrasound is preferred before 4-6 months; plain radiographs after the ossific nucleus appears.
- Untreated DDH is the leading cause of early-onset hip osteoarthritis in young adults.
- The Pavlik harness is contraindicated in stiff, irreducible hips and in infants over 6 months.
References
- AAP 2016 — American Academy of Pediatrics clinical report on evaluation and referral for developmental dysplasia of the hip in infants
- POSNA — Pediatric Orthopaedic Society of North America clinical resources on DDH
- AAOS 2014 — American Academy of Orthopaedic Surgeons clinical practice guideline on detection and nonoperative management of pediatric DDH
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