Weekly Case

Title : case 220

Age / Sex : 3 / M




Age
/ Sex : 3/M



Chief
complaint : R
ight 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 ([email protected])



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





Correct Answer
Name Institution
total applicants 8
correct answer 6
정진영 삼성서울병원
김혜린 삼성서울병원
박희진 강북삼성병원
윤민아 서울대병원
김건우 (전공의) 강동경희대학교병원
최희석 부평세림병원

Comment