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Larsen's Syndrome

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Topic updated on 02/01/14 3:26pm
Introduction
  • A rare genetic disorder with characteristic findings of ligamentous hyperlaxity, abnormal facial features, and multiple joint dislocations
    • dislocations include
      • hips
      • knees (usually bilateral)
      • shoulders
      • elbows (radial head)
  • Epidemiology
    • estimated to be 1 in 100,000 live births
  • Genetics
    • autosomal dominant (AD) and recessive (AR) inheritance patterns
      • AD linked to a mutation of the gene encoding filamin B
      • AR linked to carbohydrate sulfotransferase 3 deficiency 
  • Associated conditions
    • orthopaedic manisfestations
      • hand deformities
      • scoliosis
      • clubfeet
      • cervical kyphosis q
        • may present with extremity weakness secondary to myelopathy
        • caused by hypoplasia of the cervical vertebrae
Presentation
  • Symptoms
    • patients have normal intelligence
  • Physical exam
    • hypotonia 
      • uncommon but may be due to cervical compression
    • abnormal facial features 
      • flattened nasal bridge
      • hypertelorism
      • prominent forehead
    • hands 
      • long cylindrical fingers that do not taper
      • wide distal phalanx at the thumb
    • elbows
      • bilateral radial head dislocations may be present
    • knees
      • look for bilateral knee dislocations
    • foot deformities
      • equinovarus  
      • eqinovalgus
      • clubfeet
Imaging
  •  Radiographs
    • recommended
      • AP and lateral of cervical spine
        • during first year of life
      • AP pelvis and lateral of hips
        • ultrasound if less than 3 months
    • findings
      • hypoplasia of vertebrae
      • cervical kyphosis with subluxation
      • hip dislocation
  • MRI  
    • recommended 
      • cervical kyphosis 
      • myelopathy 
Treatment
  • Cervical kyphosis
    • operative
      • posterior cervical fusion
        • indications
          • patients with significant kyphosis but no neurologic deficits
          • recommended to be performed during the first 18 months of life to prevent neurological deterioration
      • anterior/posterior cervical decompression and fusion
        • indications
          • cervical kyphosis with neurologic deficits
  • Hip dislocations
    • nonoperative
      • closed reduction under anesthesia
        • indications
          • may be attempted but rarely successful
    • operative
      • open reduction of hip dislocation
        • indications
          • failed closed reduction
          • decreased range of motion secondary to contractures around hip
          • unilateral hip dislocation
          • bilateral hip dislocation
            • controversial
            • if considering, perform early and only once
  • Knee dislocations
    • nonoperative
      • closed reduction and casting
        • indications
          • may be attempted but rarely successful
    • operative
      • open reduction with femoral shortening and collateral ligament excision
        • indications
          • knee dislocations that remain unstable after closed reduction

 

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(OBQ04.201) A 5-year-old boy has a history of bilateral dislocated radial heads, bilateral knee dislocations, and flattened facies. What other important orthopaedic-related condition must be checked in this patient? Topic Review Topic

1. congenital vertical talus
2. congenital trigger thumb
3. tibial hemimelia
4. cervical kyphosis
5. congenital pseudoarthrosis of clavicle

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