Musculoskeletal · Pediatric Orthopedics

Developmental Dysplasia of the Hip

USMLE2PANCE
7

Bets

The facts most likely to be tested

Press 1–5 to rate · ↑↓ to navigate

1

The Barlow maneuver attempts to dislocate a reduced (located) hip by adducting and pushing the hip posteriorly, revealing hip instability.

Confidence:
2

The Ortolani maneuver attempts to relocate a dislocated hip by abducting and lifting the femoral head anteriorly.

Confidence:
3

Ultrasound of the hip is the diagnostic modality of choice for infants younger than 4 to 6 months of age.

Confidence:
4

AP pelvis radiographs are preferred over ultrasound beginning at about 4 months of age, as the ossifying femoral head progressively obscures ultrasound assessment.

Confidence:
5

Breech presentation, female sex, and family history are the most significant risk factors for developing the condition.

Confidence:
6

The Pavlik harness is the most widely used initial brace for infants younger than 6 months, holding the hip in flexion and abduction; comparative evidence among abduction braces is limited.

Confidence:
7

Delayed diagnosis leads to persistent acetabular dysplasia, limb-length discrepancy, gait abnormalities, and early hip osteoarthritis; avascular necrosis is chiefly a complication of reduction or bracing.

Confidence:

Vignette unlocked

A 3-week-old female infant is brought to the clinic for a routine well-child check. She was born at 39 weeks gestation via breech presentation. On physical examination, the pediatrician notes an asymmetric gluteal fold and a palpable clunk when performing an abduction maneuver on the left hip (positive Ortolani). The right hip examination is unremarkable. The infant is otherwise healthy and meeting all developmental milestones.

What is the most appropriate next step in management?

+Reveal answer

Hip ultrasound

The patient presents with classic signs of developmental dysplasia of the hip (breech history, asymmetric folds, positive Ortolani/Barlow), and ultrasound is the diagnostic test of choice for infants under 6 months.

Mo

Depth

Full handout

High yield triage

Etiology / Epidemiology

Common in breech presentation, female sex, and family history. Results from abnormal acetabular development.

Clinical Manifestations

Positive Ortolani and Barlow maneuvers. Asymmetric skin folds and leg length discrepancy.

Diagnosis

Hip ultrasound is the diagnostic modality of choice for infants younger than 4-6 months (before femoral head ossification). Radiographs become preferred once the ossific nucleus appears, generally after 4-6 months.

Treatment

Pavlik harness is the first-line treatment. Avoid forced abduction to prevent avascular necrosis.

Prognosis

Early detection prevents persistent dysplasia, gait abnormalities, and early osteoarthritis; avascular necrosis is mainly a treatment-related risk.

Full handout

Epidemiology & Etiology

Incidence is highest in first-born females and those with a history of breech positioning in utero. Mechanical factors like oligohydramnios and swaddling practices contribute to joint laxity. Genetic predisposition is significant, siblings of affected patients warrant careful clinical hip screening, with imaging per standard risk-based criteria.

Pertinent Anatomy

The acetabulum is shallow, failing to adequately cover the femoral head. This anatomical instability allows the femoral head to subluxate or dislocate from the acetabulum.

Pathophysiology

Persistent instability leads to secondary changes in the acetabular labrum and capsule. If untreated, the femoral head remains displaced, the acetabulum flattens, and a false acetabulum may form, producing fixed structural deformity. Chronic dislocation results in permanent structural deformity and early-onset osteoarthritis.

Clinical Manifestations

Infants present with a positive Ortolani (reduction of dislocated hip) or Barlow (dislocation of reduced hip) maneuver. Look for asymmetric inguinal skin folds and limited hip abduction. Red flag: A late-presenting child may exhibit a Trendelenburg gait or a painless limp.

Diagnosis

Hip ultrasound is the diagnostic modality of choice for infants younger than 4-6 months due to cartilaginous anatomy. After 4-6 months, the femoral head ossifies, making AP pelvis radiographs the preferred study. The alpha angle on ultrasound is the critical metric for assessing acetabular depth.

Treatment

The Pavlik harness is the gold standard for infants <6 months, maintaining the hip in flexion and abduction. Avoid forced or extreme abduction in any brace, which is the main driver of avascular necrosis; rigid abduction splints such as the von Rosen splint are an accepted alternative to the Pavlik harness. If the harness fails or the patient is older, closed reduction under anesthesia or open surgical reduction is required.

Prognosis

Early intervention leads to excellent outcomes with normal hip development. Delayed diagnosis significantly increases the risk of permanent hip dysplasia, chronic pain, and the need for total hip arthroplasty in early adulthood.

Differential Diagnosis

Septic arthritis: acute fever and refusal to bear weight

Legg-Calvé-Perthes disease: idiopathic avascular necrosis in older children

Slipped Capital Femoral Epiphysis: adolescent onset with external rotation

Transient synovitis: follows viral illness, self-limiting

Teratologic hip dislocation: fixed, non-reducible dislocation present at birth, often associated with neuromuscular conditions (e.g., arthrogryposis, myelomeningocele)

Developmental Dysplasia of the Hip — USMLE2 / PANCE Board Prep | MoBets