Muscular disorders PEDS

• Developmental dysplasia of the hip (DDH)


  Infantile hip instability, dislocation, or shallowness of the hip socket
• DDH is usually detected at birth or during infancy and early development
• DDH is the most common disorder affecting the hip joint in children younger than age 3 years
• DDH can be unilateral or bilateral
• Degrees of hip dysplasia


  • Subluxtable
  • Dislocatable
  • Dislocated
• Normally, the head of the femur


  • Fits snugly into the acetabulum, allowing the hip to move properly
• In developmental dysplasia of the hip


  • Flattening of the acetabulum prevents the head of the femur from rotating adequately
• The disorder is almost six times more common in females than males
• The left hip is more commonly affected than the right hip due to positioning in utero
• DDH is associated with congenital torticollis, plagiocephaly, metatarsus adductus, clubfoot, and other lower limb deformities
• DDH may be more common in term infants than it is in preterm infants less than 36 weeks' gestation
• Complications


  • Degenerative hip changes
  • Neurovascular injury related to surgery
  • Abnormal acetabular development
  • Lordosis
  • Joint malformation
  • Back pain in those with bilateral hip dislocation
  • Sciatic nerve injury (paralysis)
  • Avascular necrosis of the femoral head
  • Soft-tissue damage
  • Unstable gait, pain with ambulation, functional scoliosis, valgus deformity of the ipsilateral knee, hip osteoarthritis, and lower back pain
  • Permanent disability
  • Delayed ambulation
  • Growth disturbance of the proximal femur (rare)
• DDH screening


  Should be initiated in the newborn period and continue until about age 9 months or when the child can walk independently
• Early detection is especially crucial at ages 2 and 4 weeks
• History


  • Breech delivery
  • Family history (first-degree relative)
  • Family history of ligamentous laxity
• Physical Findings


  • Asymmetrical thigh or gluteal folds
  • Decreased mobility or flexibility on one side
  • Limited abduction on the dislocated side (typically in children older than age 3 months)
  • Uneven level of the knees
  • Swaying from side to side ("duck waddle"), limping, or toe walking because of uncorrected bilateral dysplasia
  • Leg length discrepancies, such as shorting of the affected limb
• Positive Ortolani and Barlow signs


  In infants up to age 6 months
• Positive Trendelenburg sign


  In children older than age 4 years
• Dislocation distinguished from benign joint movement

  Via the "jerk" or "clunk" sensation elicited during testing for the Ortolani or Barlow sign, where the benign movements are considered solely a "hip click" without the sensation of instability and are not suggestive of DDH
• Ortolani sign


  Confirms DDH
• Ortolani sign


  1. Place the infant on the back

  2. Flex the infant's knees, placing your thumbs on the middles of the thighs and your fingers over the areas of the greater trochanters (near the hips)

  3. Abduct the legs as you move the knees outward and down

  4. You will hear a clunk and feel the head of the femur slide over the acetabular rim, causing hip reduction
• Barlow sign


  1. Keeping the same hand position used to assess for the Ortolani sign and flexing the infant's knees, adduct the legs until your thumbs touch each other

  2. You will feel the head of the femur slip out of the hip socket and hear a clunk that sounds similar to a light switch being turned off or on
• Trendelenburg sign


  1. When the child rests weight on the side of the dislocation and lifts the other knee, the pelvis drops on the unaffected side because abductor muscles in the affected hip are weak

  2. When the child stands with weight on the unaffected side and lifts the other knee, the pelvis remains horizontal

  3. Evaluate the strength of the gluteus medius muscle
• Imaging studies are recommended before 6 months of age in infants with one or more of the following conditions: breech presentation in utero, history of clinical instability, or family history
• Radiography


  Generally not useful in children younger than age 6 months, shows the location of the femur head and a shallow acetabulum
• Ultrasonography


  Used in infants younger than age 6 months with a positive instability examination finding, identifies subluxation or dislocation of the hip and dysplasia of the acetabulum, guiding the decision to initiate brace treatment
• Sonography and magnetic resonance imaging


  Reveal laxity, subluxation, dislocation, and reducibility and are used to assess reduction
• Hip arthrography


  Can help to decide the treatment approach (open or closed reduction procedure)
• The younger a child with DDH begins treatment, the more effective and greater improved the outcome
• Treatment that begins after age 5 years rarely restores satisfactory hip function
• Treatment for infants younger than age 6 months


  • Bracing with a Pavlik harness (ages 1 to 2 months)
  • Semirigid orthosis (ages 2 to 8 months)
• Pavlik harness


  Worn continuously for 2 to 3 months; then a night splint for another month
• von Rosen splint


  Used for initial treatment
• Treatment for children older than age 6 months or if bracing is ineffective


  • Closed reduction
  • Hip spica cast for 6 to 12 weeks, followed by an abduction brace; possibly skin traction a few weeks prior to femoral repositioning
  • Reapplication of hip spica cast if hip instability remains
• Treatment for children older than age 24 months or if previous treatment was ineffective


  • Open reduction
  • Femoral shortening (typically for children older than age 3 years)
  • Pelvic or femoral osteotomy to correct bone deformity
• All procedures followed by immobilization in a hip spica cast
• Medications


  Acetaminophen for pain
• No dietary restrictions
• Activity as tolerated
• Gentle closed reduction under arthrography


  To further abduct the hips, followed by a hip spica cast for 6 to 12 weeks