Objectives To explore whether changes of MRI-defined synovitis and bone marrow lesions (BMLs) are related to changes in joint tenderness in a 5-year longitudinal study of the Oslo hand osteoarthritis (OA) cohort.

Methods We included 70 patients (63 women, mean (SD) age 67.9 (5.5) years). BMLs and contrast-enhanced synovitis in the distal and proximal interphalangeal joints were evaluated on 0–3 scales in n=69 and n=48 patients, respectively. Among joints without tenderness at baseline, we explored whether increasing/incident synovitis and BMLs were associated with incident joint tenderness using generalised estimating equations. Among joints with tenderness at baseline, we explored whether decreasing or resolution of synovitis and BMLs were associated with loss of joint tenderness. We adjusted for age, sex, body mass index, follow-up time and changes in radiographic OA.

Results Among joints without tenderness at baseline, increasing/incident synovitis and BMLs were seen in 45 of 220 (20.5%) and 47 of 312 (15.1%) joints, respectively. Statistically significant associations to incident joint tenderness were found for increasing/incident synovitis (OR=2.66, 95% CI 1.38 to 5.11) and BMLs (OR=2.85, 95% CI 1.23 to 6.58) independent of structural progression. We found a trend that resolution of synovitis (OR=1.72, 95% CI 0.80 to 3.68) and moderate/large decreases of BMLs (OR=1.90, 95% CI 0.57 to 6.33) were associated with loss of joint tenderness, but these associations were non-significant.

Conclusions The Oslo hand OA cohort is the first study with longitudinal hand MRIs. Increasing synovitis and BMLs were significantly associated with incident joint tenderness, whereas no significant associations were found for decreasing or loss of synovitis and BMLs.