Mega os trigonum in progressive pseudorheumatoid dysplasia.
BACKGROUND
Progressive pseudorheumatoid dysplasia (PPRD), a noninflammatory condition, needs to be differentiated diagnostically from juvenile rheumatoid arthritis (JRA).


OBJECTIVE
Demonstration of an unusually large and often early-appearing os trigonum helps distinguish PPRD from JRA.


METHODS
Ankle images in four children with PPRD were reviewed.


RESULTS
The os trigonum was abnormally enlarged in all PPRD subjects and was shown to have appeared or fused earlier than normal in two subjects.


CONCLUSIONS
A large and early os trigonum ossification helps differentiate PPRD from JRA.
Oestreich
Alan E
AE
Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA. oestreich.ae@chmcc.org
D001171:Arthritis, Juvenile / Q000000981:diagnostic imaging*; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D010009:Osteochondrodysplasias / Q000000981:diagnostic imaging*; D011859:Radiography; D013628:Talus / Q000000981:diagnostic imaging* / Q000473:pathology*