To investigate associations between engagement in knee bending (stair climbing, kneeling, squatting, heavy lifting, getting in/out of a squatting position) and synovitis prevalence on noncontrast magnetic resonance imaging (MRI) in individuals at risk of and with knee osteoarthritis.
We included baseline data from 594 participants (mean ± SD age 61.5 ± 8.9 years, 61% had Kellgren/Lawrence grade ≥2; 59% were female; mean ± SD body mass index was 30.7 ± 4.8 kg/m
The prevalence of grade ≥1 Hoffa synovitis and effusion synovitis equaled 59% (n = 353) and 62% (n = 366), respectively. Adjusted for confounders, kneeling for ≥30 minutes during a single day was associated with grade ≥1 Hoffa synovitis prevalence (odds ratio [OR] 1.65 [95% confidence interval (95% CI) 1.11-2.47]). Participants engaging in this activity ≤1 day per week had greater odds for prevalent Hoffa synovitis than those who did not perform the activity (OR 1.88 [95% CI 1.11-3.18]). No other significant associations were found. Sensitivity analyses yielded similar findings.
In this selected sample with a preponderance of grade ≥1 Hoffa and/or effusion synovitis on noncontrast MRI, only prolonged kneeling was associated with Hoffa synovitis prevalence. Replication in other samples is warranted.