MRI-Assessed Subchondral Cysts and Incident Knee Pain and Knee Osteoarthritis: data from the Multicentre Osteoarthritis Study.
OBJECTIVE
Our aim was to examine whether knee subchondral cysts, measured on magnetic resonance imaging (MRI), were associated with incident knee OA outcomes.


METHODS
We used longitudinal data from the Multicentre Osteoarthritis Study (MOST), a community-based cohort of risk factors for knee OA. Participants without a history of knee surgery and/or inflammatory arthritis (i.e., rheumatoid arthritis and gout) were followed for 84-months for incident outcomes; i) radiographic knee OA (RKOA) (Kellgren-Lawrence (KL) ≥2), ii) symptomatic RKOA (RKOA and frequent knee pain) and iii) frequent knee pain (in participants with/without RKOA). Subchondral cysts were scored on baseline MRIs of one knee in a subset of participants. Multiple logistic regression, with adjustment for participant characteristics and other baseline knee MRI findings, was used to assess whether subchondral cysts were predictive of incident outcomes.


RESULTS
Incident RKOA, symptomatic RKOA and frequent knee pain occurred in 22.8%, 17.0% and 28.8% (no RKOA) / 43.7% (with RKOA) of participants eligible for each outcome, respectively. Adjusting for age, sex and BMI, the presence of subchondral cysts was not associated with incident RKOA, but was associated with increased odds of incident symptomatic RKOA (OR: 1.92 (95% CI: 1.16 to 3.19) and knee pain in those with baseline RKOA (2.11 (0.87 to 5.12). Stronger and significant associations were observed for outcomes based on consistent reports of frequent pain within approximately one month.


CONCLUSIONS
Subchondral cysts are likely to be a secondary phenomenon, rather than a primary trigger, of RKOA, and may predict symptoms in knees with existing disease.
['Perry|Thomas A|TA|https://orcid.org/0000-0002-0499-3033', "O'Neill|Terence W|TW|", 'Tolstykh|Irina|I|', 'Lynch|John|J|', 'Felson|David T|DT|https://orcid.org/0000-0002-2668-2447', 'Arden|Nigel K|NK|', 'Nevitt|Michael C|MC|']
Subchondral cysts Incident knee OA Osteoarthritis (OA)