Ten-year follow-up of SpA-related oligoarthritis involving the knee: the presence of psoriasis but not HLA-B27 or baseline MRI bone oedema predicts outcome.
OBJECTIVE
Bone marrow oedema (BMO) and HLA-B27 are poor prognostic factors in axial SpA, and psoriasis is a poor prognostic factor in small-joint polyarthropathy. The aim of this study was to investigate the influence of HLA-B27, MRI BMO and psoriasis on long-term outcomes in early SpA-related knee joint oligoarthritis.


METHODS
Patients with SpA-related oligoarthritis with knee involvement were recruited. Baseline assessment included ESSG criteria, RF, HLA-B27 and MRI. The degree of MRI BMO was determined on fat-suppression sequences and scored using the whole-organ magnetic resonance imaging score (WORMS) (range 0-45). Patients were treated at the discretion of their rheumatologist and followed up for 10 years. Outcome assessments included joint counts, functional and symptomatic questionnaire, CRP and radiographic assessment for OA.


RESULTS
Forty-four patients were recruited [mean age 32 years (range 15-59 years), 70% male] with a mean disease duration at baseline of 9.75 months (1-48 months). Twenty-six (59%) patients (mean age 43 years, 65% male) returned for follow-up after a mean of 10 years (range 8.4-12.6 years). Ten (38%) patients had persistent clinical synovitis and 31% of knees had secondary radiographic OA. Global outcome was poor/very poor in 69% of cases. The only factor predicting outcome at 10 years was psoriasis, but neither HLA-B27 nor BMO. PsA patients had significantly worse global outcome compared with ReA (P = 0.036), and significantly worse symptomatic (P = 0.001) and functional (P = 0.001) outcome compared with other subtypes.


CONCLUSIONS
SpA-related knee joint oligoarthritis has significant long-term clinical and radiological morbidity despite standard treatments. HLA-B27 and MRI BMO were not predictors of poor outcome as they are in axial SpA; however, the presence of psoriasis predicted significantly worse outcome.
Academic Section of Musculoskeletal Disease, Leeds Institute of Molecular Medicine, Chapel Allerton Hospital, Chapeltown Road, Leeds LS7 4SA, UK.
Alexander N
AN
Bennett
Helena
H
Marzo-Ortega
Ai Lyn
AL
Tan
Elizabeth M A
EM
Hensor
Mike
M
Green
Paul
P
Emery
Dennis
D
McGonagle
D000293:Adolescent; D000328:Adult; D001168:Arthritis / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology*; D001175:Arthrography / Q000706:statistics & numerical data; D004487:Edema / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D015796:HLA-B27 Antigen / Q000235:genetics*; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D011379:Prognosis; D000091402:Prohibitins; D011446:Prospective Studies; D011565:Psoriasis / Q000235:genetics / Q000473:pathology*; D025241:Spondylarthritis / Q000000981:diagnostic imaging / Q000235:genetics / Q000473:pathology*; D055815:Young Adult
D015796:HLA-B27 Antigen; C000717331:PHB2 protein, human; D000091402:Prohibitins