Knee pain and radiographic osteoarthritis interact in the prediction of levels of self-reported disability.
OBJECTIVE
To determine predictors of disability depending on whether joint deformity and pain reporting exist independently or concurrently.


METHODS
Subjects were 154 volunteers for an osteoarthritis screening examination. Eligible subjects completed questionnaires for physical function, pain, and depressive symptoms; underwent evoked pain testing for tenderness assessment; and had anteroposterior and lateral radiographs taken of both knees. Two blinded rheumatologists scored the images using Kellgren-Lawrence criteria to determine presence of deformity.


RESULTS
Subjects were divided into 3 subgroups based on radiographic evidence of deformity and self-reported pain. Disability was greatest when pain and deformity occurred together (F[2,151] = 18.8, P < 0.0001). Self-reported disability in the absence of deformity was predicted by body mass index, pain threshold, and anxiety symptoms; disability was predicted by the number of osteophytes and depressive symptoms when pain and deformity occurred together.


CONCLUSIONS
Self-reported disability in osteoarthritis of the knee is greatest with concurrent pain and joint deformity. When pain and deformity do not cooccur, disability appears to be related to separate factors, including anxiety and pain threshold (e.g., tenderness).
Williams
David A
DA
The University of Michigan, Ann Arbor, MI 48106, USA. daveawms@med.umich.edu
Farrell
Michael J
MJ
Cunningham
Jill
J
Gracely
Richard H
RH
Ambrose
Kirsten
K
Cupps
Thomas
T
Mohan
Niveditha
N
Clauw
Daniel J
DJ
D000368:Aged; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D010146:Pain / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011859:Radiography; D012044:Regression Analysis; D011795:Surveys and Questionnaires