To investigate the two-year course of pain and osteoarthritic features on magnetic resonance imaging (MRI) in the thumb base.
Patients in the Hand Osteoarthritis in Secondary Care (HOSTAS) cohort who had received radiographic examination, MRI, and clinical examination of the right thumb base at baseline and who had a 2-year follow-up period were studied. Pain on palpation of the thumb base was assessed on a 0-3 scale. MRIs were analyzed with the Outcome Measures in Rheumatology (OMERACT) thumb base osteoarthritis MRI scoring system for synovitis, bone marrow lesions (BMLs), subchondral bone defects, cartilage space loss, osteophytes, and subluxation. Radiographs were assessed for osteophytes and joint space narrowing. We studied the associations of changes in synovitis and BMLs with changes in pain using a logistic regression model adjusted for radiographic damage, with values expressed as odds ratios (ORs) and 95% confidence intervals (95% CIs).
Of 165 patients, 83% were women and the mean age was 60.7 years. At baseline, 65 patients had thumb base pain. At 2-year follow-up, pain had decreased in 32 patients and increased in 33 patients. MRI features remained stable in most patients. Structural MRI features generally deteriorated, while synovitis and BMLs improved in some individuals and deteriorated in others. Change in radiographic osteophytes rarely occurred (n = 10). Increased synovitis (odds ratio [OR] 3.4 [95% CI 1.3-9.3]) and increased BMLs (OR 5.1 [95% CI 2.1-12.6]) were associated with increased pain. Decreased BMLs appeared to be associated with decreased pain (OR 2.7 [95% CI 0.8-8.9]), and reductions in synovitis occurred too infrequently to calculate associations.
Over 2 years, thumb base pain fluctuated, while MRI features changed in a minority of patients with hand osteoarthritis. Changes in synovitis and BMLs were associated with changes in pain on palpation, even after adjustment for radiographic damage.