|
Age / Sex : 3 / M
Age
/ Sex : 3/M
Chief
complaint : Right Forearm Supination Difficulty
1) What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of
this case.
* Send Application Answers to In Sook Lee, MD (lis@pusan.ac.kr)
Courtesy : Ik Yang, Kangnam Sacred Heart Hospital, Hallym University
Diagnosis: Proximal Radioulnar Synostosis
Discussion
Findings: Altered configuration of proximal radioulnar joint
No bony fusion
No posterior or anterior dislocation
Normal appearing radial head
Differential Diagnosis:
Diagnosis: Congenital
radioulnar synostosis
Discussion:
Natural
history, Etiology and Embryology
- First described by Sandifort in
1793
- Generally not discovered
until age 3-5
-
Usually sporadic, can be associated with family history, autosomal dominant
with variable expression
- Embryology : failure of longitudinal
segmentation(separation of distal radius and ulna, period of sharing common
perichondrium)
- 60%
bilateral
-
M=F
- Symptom : lack of pronation
and suppination in an infant
-
Associated skeletal anomalies : DDH, club feet, missing or diminutive thumb, coalescence
of carpal bones, symphalangism, dislocation of radius
-
Associated syndromes : Aperts, Williams, Klinefelter's, Nievergelt-Pearlman, acrocephalopolysyndactyly
Classification
- By Cleary and
Omer
1. Type I: synostosis does not involve
bone, associated with reduced, normal-appearing, radial head
2. Type II: visible osseous synostosis but
otherwise unremarkable findings
3. Type III: visible osseous synostosis
with a hypoplastic and posteriorly dislocated radial head
4. Type IV: short osseous synostosis with
an anteriorly dislocated radial head (mushroom shaped)
Radiologic
findings
- Spectrum
of anatomic variation
-
Range of synostosis from proximal fibrous union to total synostosis of radius
and ulna
-
Radial head dislocation
-
Forearm shortening
-
Varying continuity of cancellous bone throughout the coalition
-
Radial shaft bowing
Management
- Observation : no
functional deficits
- Surgical
correction : functional loss of forearm axial rotation
References:
1.
Alison
M. The developmental spectrum of proximal radioulnar synostosis. Skeletal
Radiol. 2010;39:49-54
2.
http://gait.aidi.udel.edu/educate/conrad.htm
|
