Bone marrow lesions on magnetic resonance imaging in hand osteoarthritis are associated with pain and interact with synovitis

Summary Objective To determine the association between bone marrow lesions (BMLs) and (teno)synovitis as assessed on magnetic resonance (MR) imaging in patients with pain in hand osteoarthritis (OA). Methods In 105 consecutive primary hand OA patients (83% women, mean age 59 years), who were diagnosed by rheumatologists and included in the HOSTAS (Hand OSTeoArthritis in Secondary care) cohort, contrast-enhanced MR imaging of right distal and proximal interphalangeal joints were obtained. In 92 patients joint site specific pain upon palpation was assessed within 3 weeks of MRI examination. MR features were scored (0-3) following the Oslo hand OA score: BMLs, synovitis, cysts, flexor tenosynovitis (FTS). Additionally, extensor tendon inflammation (ETI)(0-3) was scored. Odds ratios (OR, 95%CI) were calculated using generalised estimating equations for MR features with joint pain, adjusted for putative confounders. Stratified analyses were performed to investigate interaction. Results BMLs, synovitis, cysts, FTS and ETI were demonstrated in 56%, 90%, 22%, 16% and 30% of patients, respectively. BMLs (grade 2/3 vs 0: 3.5 (1.6-7.7)) and synovitis (3 vs 0: OR 3.6 (95%CI 1.9-6.6)) were severity-dependent associated with joint pain, but FTS and ETI were not. Stratified analyses showed that BMLs did not associate with pain in the absence of synovitis, whereas synovitis was associated with pain in the absence of BMLs. Interaction was seen between BMLs and synovitis grade 2 or 3. Conclusion In hand OA patients severe synovitis is associated with joint pain, which is worsened when BMLs co-occur, suggesting synovitis as primary target of treatment.