Performance of hands and feet radiographs in differentiation of psoriatic arthritis from rheumatoid arthritis.
OBJECTIVE
The purpose of this study was to determine useful radiographic findings for differentiating psoriatic arthritis (PsA) from rheumatoid factor (RF)-positive or -negative rheumatoid arthritis (RA) in Japanese patients.


METHODS
We accrued 85 patients with PsA. Controls included 135 patients with RA (85 RF-positive, 50 RF-negative) matched for gender and disease duration with PsA patients. Radiographs of hands and feet were obtained, and distal interphalangeal (DIP) erosive disease, joint osteolysis, tuft osteolysis, juxta-articular bony proliferation (JBP), periosteal new bone formation and bony ankylosis, which were identified using the definitions developed by an earlier study, were compared between the PsA and RA groups.


RESULTS
For radiographic features of hands, the frequencies of JBP, periosteal new bone, and diffuse soft tissue swelling of the fingers were significantly higher in PsA patients than in RF-positive RA patients. However, only the frequency of JBP significantly differed between PsA and RF-negative RA patients. In feet, the frequencies of DIP erosive disease, tuft osteolysis, JBP, and diffuse soft tissue swelling of the toes were significantly higher in PsA patients than in RF-positive RA patients. However, only the frequency of JBP significantly differed between PsA and RF-negative RA patients.


CONCLUSIONS
JBP was the most important radiographic feature for discriminating PsA from both RF-positive and -negative RA, confirming the study by the CASPAR group that showed that JBP is the only radiologic feature that can discriminate PsA from other inflammatory arthritides. This study showed the utility of plain radiographs for diagnosis of PsA.
Institute of Rheumatology, Department of Dermatology, Tokyo Women's Medical University, Tokyo, Japan. naomi@ior.twmu.ac.jp
Naomi
N
Ichikawa
Atsuo
A
Taniguchi
Satomi
S
Kobayashi
Hisashi
H
Yamanaka
D000328:Adult; D000368:Aged; D015535:Arthritis, Psoriatic / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000473:pathology; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000473:pathology; D001842:Bone and Bones / Q000473:pathology; D016022:Case-Control Studies; D049109:Cell Proliferation; D003937:Diagnosis, Differential; D005260:Female; D005528:Foot / Q000000981:diagnostic imaging*; D006225:Hand / Q000000981:diagnostic imaging*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D010012:Osteogenesis; D010014:Osteolysis / Q000000981:diagnostic imaging; D011859:Radiography; D012217:Rheumatoid Factor / Q000097:blood
D012217:Rheumatoid Factor