Quantitative assessment of knee effusion-synovitis assessment in older adults: Associations with knee structural abnormalities

Objective: To describe the natural history of quantitatively measured knee effusion-synovitis and the longitudinal associations between effusion-synovitis and knee structural factors including cartilage defects, cartilage volume, subchondral bone marrow lesions and meniscal pathology in older adults.

Methods: A total of 406 subjects were randomly selected (mean 62 years, 50% females) at baseline and followed up 2.7 years later. T2 or T1-weighted fat saturation magnetic resonance imaging (MRI) was used to assess knee effusion-synovitis maximal area, cartilage defects, cartilage volume, bone marrow lesions (BMLs) and meniscal pathology at baseline and follow-up. Multivariable generalized linear regressions were performed to analyze the associations between maximal area of effusion-synovitis and other joint structural factors after adjustment for age, gender, BMI, tibial bone area and/or radiographic osteoarthritis.

Results: Over 2.7 years of follow-up, the size of effusion-synovitis increased in 29%, remained stable in 50% and decreased in 22% of the participants. Baseline effusion-synovitis maximal area was significantly associated with changes in knee cartilage defects (β: 0.18, 95%CI: 0.07, 0.29), BMLs (β: 0.17, 95%CI: 0.05, 0.30), and cartilage volume (β: -0.40, 95%CI: -0.71, -0.09) but not with change in meniscal pathology. In contrast, baseline structural measures were not associated with change or increase in effusion-synovitis maximal area.

Conclusion: Knee effusion-synovitis was not static in older adults. It was predictive of, but not predicted by, other structural abnormalities suggesting a potential role in knee early osteoarthritic changes. This article is protected by copyright. All rights reserved.