DDH isn’t just one thing…
Developmental dysplasia of the hip (DDH) encompasses a spectrum of conditions related to the development of the hip:
- Dysplasia: Abnormality of the shape of the hip joint (usually shallowness of the acetabulum, involving the superior and anterior margins)
- Subluxatable/subluxable: The femoral head is reduced (i.e., within the acetabulum) at rest but can be partially dislocated or subluxated with examination maneuvers.
- This is a hip with mild instability or laxity.
- Dislocatable: The femoral head is reduced at rest but can dislocate in other positions or with examination maneuvers.
- This is a hip with instability.
- Subluxation: The femoral head is partially outside of the acetabulum but remains in contact with it.
- Reducible: The hip is dislocated at rest, but the femoral head can be positioned into the acetabulum with manipulation (generally flexion and abduction).
- Dislocation: Complete loss of contact between the femoral head and the acetabulum.
In short, acetabular dysplasia, or hip dysplasia, is a disorder that occurs when the acetabulum (hip socket) is shallow and doesn’t provide sufficient coverage of the femoral head (ball), causing instability of the hip joint. Hip subluxation is when the ball started to come out of the socket but did not fully come out or dislocate.
Risk factors
- Breech positioning during 3rd trimester
- First-born
- Female
- +Family history
AAP/POSNA recommends imaging before 6mo in children with breech positioning or +family history.
Parents of children with risk factors should also practice safe swaddling technique with the goal of allowing free hip movement.
Clinical findings in kids with DDH
- Clinical pearl: DDH is bilateral in as many as 20-37% of cases!
Infants <3mo:
- Clinical findings in unilateral DDH:
- Hip instability (+Barlow, +Ortolani)
- *Asymmetric leg creases (inguinal, gluteal, thigh, or popliteal)
- *Apparent shortening of femur (+Galeazzi sign)
- *absent in bilateral disease
Infant should be placed on a firm surface with hips flexed to 90º in order to perform the Barlow and Ortolani maneuvers. The diaper should be off during the exam.
Barlow maneuver: Depression/adduction dislocates an unstable hip
Ortolani maneuver: Elevation/abduction relocates a dislocated hip
- Clinical pearl: Hip clicks without instability are NOT clinically significant in infants!
Infants >3mo:
- Clinical findings in unilateral DDH:
- Limitation of hip abduction in 90° of flexion
- *Apparent shortening of the femur (+Galeazzi)
- Laterally rotated posture in prone position
- *Marked asymmetry of leg creases (inguinal, gluteal, thigh, or popliteal)
- *absent in bilateral disease
- Clinical pearl: Clinical diagnosis is limited in older infants because of soft tissue contracture with limitations in abduction
Galeazzi sign: appearance of shortened femur on affected side
- Unlike the Barlow and Ortolani maneuvers, the Galeazzi maneuver is not specific for DDH
Children of walking age:
- Clinical findings in unilateral DDH:
- Prominent greater trochanter
- Gluteus medius lurch (i.e., Trendelenburg gait)
- +Trendelenburg sign
- *Short leg limp, with toe-heel gait and out-toeing
- Increasing adduction contracture of the hip, with compensatory genu valgum
- *absent in bilateral disease, which may also present with excessive lordosis
Imaging
- Hip US is best for infants <4-6 months-old
- Timing: US after 4-6 weeks of age has lower rate of false positives
- Pelvic XR (AP) may be obtained for kids >4-6 months-old
Treatment
Orthopedics referral in presence of
- Unstable hip exam (i.e., +Barlow or +Ortolani)
- Positive imaging
Birth – 6mo:
- Pavlik harness, abduction brace
- Best outcomes if harness initiated before 6 weeks of age
>6 months of age:
- Operative (either closed or open reduction)
In absence of treatment, potential complications include chronic pain, degenerative arthritis, postural scoliosis, and impaired gait.
Further reading!
Blog post based on Med-Peds Forum talk by Rebecca Moore, PGY4