Objective To evaluate if two different measures of synovial activation, baseline Hoffa synovitis and effusion synovitis, assessed by MRI, predict cartilage loss in the tibiofemoral joint at 30 months follow-up in subjects with neither cartilage damage nor tibiofemoral radiographic osteoarthritis of the knee.
Methods Non-contrast-enhanced MRI was performed using proton density-weighted fat-suppressed sequences in the axial and sagittal planes and a short tau inversion recovery sequence in the coronal plane. Hoffa synovitis, effusion synovitis and cartilage status were assessed semiquantitatively according to the WORMS scoring system. Included were knees that had neither radiographic osteoarthritis nor MRI-detected tibiofemoral cartilage damage at the baseline visit. The presence of Hoffa synovitis was defined as any grade ≥2 (range 0–3) and effusion synovitis as any grade ≥2 (range 0–3). Logistic regression was performed to examine the relation of the presence of either measure to the risk of cartilage loss at 30 months adjusting for other potential confounders.
Results Of 514 knees included in the analysis, the prevalence of Hoffa synovitis and effusion synovitis at the baseline visit was 8.4% and 10.3%, respectively. In the multivariable analysis, baseline effusion synovitis was associated with an increased risk of cartilage loss. No such association was observed for baseline Hoffa synovitis.
Conclusions Baseline effusion synovitis, but not Hoffa synovitis, predicted cartilage loss. The findings suggest that effusion synovitis, a reflection of inflammatory activity including joint effusion and synovitic thickening, may play a role in the future development of cartilage lesions in knees without osteoarthritis.
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Funding This study was supported by NIH grants from the National Institute of Aging to CEL (U01-AG-18947), JT (U01-AG-18832), MCN (U01-AG-19069) and DTF (U01-AG-18820) and NIH AR47785.
Competing interests AG has received consultancies, speaking fees and/or honoraria (less than US$10 000 each) from Facet Solutions, Genzyme and Stryker, and (more than US$10 000) from Merck Serono, and is the President of Boston Imaging Core Lab (BICL). He receives research grants from General Electric Healthcare. FWR is vice president and a shareholder of BICL. MDC is a shareholder of BICL. None of the other authors have declared any possible conflict of interest.
Patient consent Obtained.
Ethics approval This study was conducted with the approval of the University of Iowa, University of Alabama, Birmingham, University of California, San Francisco and Boston University Medical Campus.
Provenance and peer review Not commissioned; externally peer reviewed.