Associations between MRI-detected early osteophytes and knee structure in older adults: a population-based cohort study

Objectives: To describe prevalence of osteophytes (OPs) detected only by magnetic resonance imaging (MRI) but not by standard X-ray in older adults and to evaluate longitudinal associations with knee structural changes. Methods: 837 participants were randomly selected from the local community and had MRI scans to assess knee OPs and other structures. OPs detected only by MRI but not by standard X-ray were defined as MRI-detected early OPs (MRI-OPs for short). OPs detected by both MRI and X-ray were defined as established-OPs. Results: The prevalence of MRI-OPs was 50% while the prevalence of established-OPs was 10% and no-OPs was 40% at total tibiofemoral (TF) compartment at baseline. Compared with no-OPs, participants with MRI-OPs had greater risks of increased cartilage defects in all TF compartments (RR 1.37, 95% CI 1.07 -1.74) and bone marrow lesions (BMLs) only in medial TF compartment (RR 1.49, 95% CI 1.06-2.11), after adjustment for age, sex, BMI, cartilage defects, BMLs and/or joint space narrowing; participants with established-OPs had greater cartilage volume loss at total (beta - 2.02, 95% CI - 3.86, - 0.17) and lateral tibial sites (beta - 5.63, 95% CI - 9.93, - 1.32), greater risks of increased cartilage defects in total (RR 1.66, 95% CI 1.15 -2.40) and medial TF compartments (RR 1.49, 95% CI 1.20-1.69) and BMLs in all TF compartments (RR 1.88, 95% CI 1.22-2.89), after adjustment for covariates. Conclusion: MRI-OPs were associated with changes in knee structures, and the associations were similar but not as prominent as those for established-OPs. These suggest MRI-OPs may have a role to play in knee early-stage osteoarthritic progression. (C) 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.