Congenital Radial Ulnar Synostosis

Topic updated on 07/25/16 8:37pm
  • In normal development the radius and ulna divide from distal to proximal
    • therefore the synostosis is usually in proximal half
  • Epidemiology
    • bilateral in 60%
  • Genetics
    • familial cases with autosomal dominant inheritance has been reported
    • patients frequently have duplication in sex-chromosome
  • Physical exam
    • children often present at 3-5 years of age
      • no pronation or supination
      • fixed in varying degree of pronation (50% of patients have > 50° of pronation)
  • Radiographs
    • recommended view
      • AP and lateral of forearm and elbow
    • findings
      • can see proximal synostosis
      • radius is heavy and bowed
  • Chromosome analysis
    • to identify duplication in sex chromosomes
  • Nonoperative
    • observation  
      • indications
        • usually preferred treatment, especially if deformity is unilateral
  • Operative 
    • osteotomy with fusion
      • surgery rarely indicated
      • indications
        • indicated to obtain functional degree of pronation
          • unilateral 
            • fix the forearm in pronation of 30°
          • bilateral
            • fix dominant forearm in pronation (10-20°) 
            • nondominan forearm in neutral
        • technique
          • use percutaneous pins to aid fusion
          • perform at ~ 5 years of age
          • cannot recreate proximal radial-ulnar joint with excision alone as it will reossify and recur 


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Qbank (4 Questions)

(OBQ08.140) The parents of a 2-year-old girl are concerned that their daughter has difficulty feeding herself from a bottle. They have noticed that she rotates her elbow in front of her body when trying to bring the bottle to her mouth. Physical exam demonstrates 10 degrees of elbow hyperextension and 160 degrees of flexion. The forearm does not actively or passively rotate. A radiograph is provided in figure A. Which of the following would be an indication for a future surgical intervention? Topic Review Topic
FIGURES: A          

1. Forearm fixed in 45 degrees of pronation
2. Forearm fixed in 30 degrees of supination
3. Patient younger than 3 years of age
4. An affected older sibling
5. Bilateral involvement

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