Patient report of both symptoms, or at least 1 positive exam finding and at least 1 symptom, could be used to identify knees at increased risk of effusion-synovitis (ES) in knees with early stage osteoarthritis (OA), either for screening purposes in clinical evaluation, or for study sample enrichment with an inflammatory phenotype. This according to a recent study that evaluated the diagnostic performance of knee physical exam findings and participant-reported symptoms for MRI-detected ES among knees with early and late-stage OA. Through the Osteoarthritis Initiative, researchers examined 344 knees with early OA (312 participants) and 216 with late-stage OA (186 participants). They found:

• For the early OA sample, the highest sensitivity for medium/large ES was achieved with a positive finding for any of the physical exam maneuvers and/or participant-reported symptoms (81.0).
• Both knee symptoms in combination had a prevalence of 11.7% and yielded the highest estimated positive predictive value (50.0) and likelihood ratio positive (5.2).
• In late-stage OA knees, exam findings and symptoms provided minimal information beyond the prevalence.