Congenital Radial Head Dislocation, Nail Patella Syndrome & Radioulnar Syntosis

Congenital radial head dislocation

Essential Information:
Congenital dislocation of the radial head is a unilateral (or bilateral) dislocation of the radiocapitellar joint, not associated with trauma that is characterized by dysmorphic changes in the capitellum and radial head.
  • Etiology
    • unknown
  • Genetics
    • not specified
    • 1/3 associated with other skeletal dysplasias
  • Incidence
    • unknown
  • Associated Conditions
    • radioulnar synostosis, ulnar dysplasia, nail-patella syndrome
 
Clinical Evaluation:
  • History / Exam Findings
    • child is usually presents with a painless loss of full elbow extension and forearm rotation
    • older child may demonstrate clicking
    • often there is a prominence seen in lateral aspect of elbow
  • Imaging / Lab Studies
    • plain radiographs show radiocapitellar dislocation and characteristic joint abnormalities
      • hypoplastic capitellum,
      • abnormally shaped radial head
      • excessive bow to proximal radius
  • Differential Diagnosis
    • distinguish from traumatic dislocation the dysmorphic radiographic changes and no history of significant trauma to the extremity
  • Classification Schemes
    • based on direction of dislocation
      • posterolateral is most common direction
Treatment:
  • Conservative
    • observation
  • Surgical
    • early presentation (infancy)
      • radial head reduction
        • must have only mild deformity of radial head and capitellum
        • technique:
          • osteotomy of radius
          • annular ligament reconstruction
    • late presentation
      • radial head excision
Outcomes:
  • Prognosis
    • conservative care:
      • most patients have minor limitations of elbow motion (extension loss) and minimal pain
    • surgical care:
      • radial head reduction
        • good if reduction maintained, otherwise fair to poor
      • radial head excision
        • generally good, however some reports of wrist pain if migration of the proximal radius is seen
  • Potential Complications
    • only related to surgical care as above
 
 
Recommended Readings
  • Mardam-Bey T, Ger E.Congenital Radial Head Dislocation.J Hand Surg Am. 1979; 4: 316-320
  • Kelly DW.J Pediatr Orthop.
 

 
Nail Patella Syndrome

 Essential Information:
This uncommon syndrome has manifestations of nail deformity along with skeletal anomalies commonly involving the knees, elbows and pelvis.  
  • Etiology
    • inherited as autosomal dominant
    • sporadic mutation
  • Genetics
    • mutation of LMX1B gene
  • Incidence
    • approximately 1 in 50,000 individuals
  • Risk Factors
    • male to female ratio is equal
    • many reported cases appear in multigenerational families
 
Clinical Evaluation:
  • History / Exam Findings
    • obvious deformity is seen in nails (thumbs are often the most severely affected)
      • split, abnormally thick, narrow, discolored nail plates (varying severity)
    • orthopaedic manifestations
      • patella: under-developed, misshaped or absent
      • elbow: hypoplastic radio-capitellar joint, webbing of anterior skin (pterygium), loss of motion
      • pelvis: abnormal bone projections (Iliac horns)
      • spine: scoliosis
    • other systems involved
      • ocular: cataracts, glaucoma
      • renal: 25% may develop nephropathy
  • Imaging / Lab Studies
    • prenatal ultrasound
    • radiographs: knee, elbow, pelvis
    • blood/urine tests for renal function
  • Classification Schemes
    • description is related to the severity of clinical manifestations
Treatment:
  • Conservative
    • screening for renal disease (also monitor blood pressure)
      • avoidance of NSAID medications
    • glaucoma screening
    • orthopaedic conditions
      • physiotherapy
      • splinting
  • Surgical (Orthopaedic)
    • related to joint abnormalities
      • resection of antecubital pterygium
      • joint contracture release (controversial)
Outcomes:
  • Prognosis (Orthopaedic)
    • most musculoskeletal manifestations are stable
    • joint subluxation (knee, elbow) may occur
  • Potential Complications
    • usually related to renal or ocular disease manifestations
 
 
Recommended Readings
  • Al-QattanMM,Al-BalwiM,EyaidW,Al-AbdulkarimI,Al-TurkiS. Congenital duplication of the palm syndrome: gene analysis and the molecular basis of its clinical features. J Hand Surg Eur Vol. 2009; 34(9):247–251
  • Mankin HJ, Jupiter J, Trahan CA.Hand and Foot abnormalities associated with genetic diseases.Hand. 2011 Mar;6(1):18-26.
      
 

  
Radioulnar Synostosis

Essential Information:
This is a rare congenital disorder, where patients have limited rotation of the forearm due to an abnormal connection between the radius and ulna.  The potential mal-positioning of the hand may cause functional problems.
  • Etiology
    • abnormal development (separation) of the forearm bones that occurs between weeks 5-7 post gestation
  • Genetics
    • most cases are sporadic
    • some inherited as autosomal dominant (variable penetrance)
  • Incidence
    • unknown, classified as a ‘rare’ disease
  • Risk Factors
    • none known
    • condition can be seen in association with:
      • Apert syndrome, arthrogryposis, carpal coalition, radial dysplasia 
 
Clinical Evaluation:
  • History / Exam Findings
    • some cases inherited, most sporadic
    • 60% are bilateral
    • on exam there is loss of forearm rotation
    • elbow usually has mild flexion contracture
    • hypermobility of wrist
  • Imaging / Lab Studies
    • x-rays
      • commonly see bone ‘bridging’ (synostosis) between the proximal radius and ulna
      • radial head dislocation, radial shaft bowing
    • CT scan
      • occasionally done to determine if the bridging is completely bony or if it has fibrous elements as well
  • Classification Schemes (Cleary et al., JBJS, 67-A: 4, 1985)
    • Type I: fibrous (no obvious bone) connection, associated with reduced radial head
    • Type II: visible osseous synostosis, associated with normal reduced radial head
    • Type III: visible osseous synostosis with a hypoplastic and posteriorly dislocated radial head
    • Type IV: short osseous synostosis with an anteriorly dislocated mushroom shaped radial head
Treatment:
  • Conservative
    • preferred if no functional deficits
  • Surgical
    • derotational osteotomy through the synostosis
      • most reliable method
      • may need to achieve rotational correction in stages
        • over-correction can cause vascular compromise
    • derotational osteotomy distal to the synostosis
      • difficult to achieve much correction due to tight interosseous membrane
    • osteotomy of synostosis and soft tissue interposition
      • associated with loss of correction
    • osteotomy with insertion of swivel
      • potential complication is loosening or failure of swivel
Outcomes:
  • Prognosis
    • most patients with unilateral deformity compensate well unless forearm is in hyper-pronation or hyper-supination
  • Potential Complications
    • post-surgical
      • loss of rotation correction
      • vascular compromise
      • compartment syndrome (in immediate post-operative period)
 
 
Recommended Readings
  • Cleary et al., "Congenital Proximal Radio-Ulnar Synostosis." JBJS, 67-A: 4, 1985
  • Rubin G, Rozen N, Bor N. Gradual Correction of Congenital Radioulnar Synostosis by an Osteotomy and Ilizarov External Fixation. J Hand Surg 2013;38A:447–452
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