9/18/2017 | BY Scott Riley, MD-Shriners Hospital for Children, Lexington, KY

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