Association between ultrasound-detected synovitis and knee pain: a population-based case–control study with both cross-sectional and follow-up data

Abstract

BackgroundAn important role for synovial pathology in the initiation and progression of knee osteoarthritis has been emphasised recently. This study aimed to examine whether ultrasonography-detected synovial changes associate with knee pain (KP) in a community population.MethodsA case–control study was conducted to compare people with early KP (n = 298), established KP (n = 100) or no KP (n = 94) at baseline. Multinomial logistic regression was used to estimate the odds ratio (OR) and 95% confidence interval (CI) between groups adjusted for radiographic osteoarthritis (ROA) severity and other confounding factors. After 1 year, 255 participants with early and established KP completed the follow-up questionnaire for changes in KP. Logistic regression with adjustment was used to determine predictors of KP worsening.ResultsAt baseline, effusion was associated with early KP (OR 2.64, 95% CI 1.57–4.45) and established KP (OR 5.07, 95% CI 2.74–9.38). Synovial hypertrophy was also associated with early KP (OR 5.43, 95% CI 2.12–13.92) and established KP (OR 13.27, 95% CI 4.97–35.43). The association with effusion diminished when adjusted for ROA. Power Doppler signal was uncommon (early KP 3%, established KP 2%, controls 0%). Baseline effusion predicted worsening of KP at 1 year (OR 1.95, 95% CI 1.05–3.64). However, after adjusting for ROA, the prediction was insignificant (adjusted OR 0.95, 95% CI 0.44–2.02).ConclusionsUltrasound effusion and synovial hypertrophy are associated with KP, but only effusion predicts KP worsening. However, the association/prediction is not independent from ROA. Power Doppler signal is uncommon in people with KP. Further study is needed to understand whether synovitis is directly involved in different types of KP.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-017-1486-7) contains supplementary material, which is available to authorized users.

Effects of carrageenan induced synovitis on joint damage and pain in a rat model of knee osteoarthritis

“…Synovitis might also be detected by Magnetic Resonance Imaging 32 or ultrasound 6 in asymptomatic human knees, and the potential contribution of subclinical synovitis to ongoing joint damage in human OA deserves further study. More sensitive measures of synovitis might be developed for serial use in rats, for example using radioisotopes and imaging, in order to help elucidate more precisely the time course of carrageenan-induced synovitis in arthritic and non-arthritic knees, and possible effects of subclinical synovitis on joint damage.…”

Associations of Symptomatic Knee Osteoarthritis With Histopathologic Features in Subchondral Bone

“…However, the mechanisms by which subchondral pathology contributes to OA pain are incompletely understood. Synovitis has also been associated with OA pain . Synovial and subchondral pathology can occur together within the same joint, but it is unknown whether these represent discrete painful pathologies that could be separate targets for therapeutic intervention.…”

Baseline self-report ‘central mechanisms’ trait predicts persistent knee pain in the Knee Pain in the Community (KPIC) cohort

“…Joint line PPTs may be influenced both by peripheral and by central sensitisation, whereas PPT at sites away from the affected joint is more likely to reflect central than peripheral sensitisation 5 . That peripheral sensitisation may contribute to poor pain prognosis is also suggested by pain prediction by radiographic OA classification, and by ultrasound evidence of synovitis 41 . Future studies should explore whether treatments to reduce peripheral sensitisation (e.g., by inhibiting inflammation or blocking nerve growth factor) can reduce knee Variables employ data from individuals reporting knee pain at baseline and responding at 1 year follow-up who also underwent clinical assessment at baseline (n ¼ 204).…”