Abstract
Objective To investigate the associations of Outcome Measures in Rheumatology (OMERACT) ultrasound scores for knee osteoarthritis (OA) with pain severity, other symptoms, and OA severity on radiographs and magnetic resonance imaging (MRI).
Methods Participants with symptomatic and mild-moderate radiographic knee OA underwent baseline dynamic ultrasound assessment according to standardized OMERACT scanning protocol. Using the published ultrasound image atlas, a physician operator obtained semi-quantitative or binary scores for ultrasound pathologies. Clinical severity was measured on Numerical Rating Score (NRS) and Knee Injury and Osteoarthritis Outcome Score (KOOS) symptoms and pain sub-scores. OA severity was assessed using the Kellgren-Lawrence grade (KLG) on X-rays and MRI osteoarthritis knee score (MOAKS) on non-contrast-enhanced MRI. Separate linear regression models were used to determine associations of ultrasound OA pathologies with pain and KOOS sub-scores, and Spearman’s correlations were used for ultrasound scores with KLG and MOAKS.
Results Eighty-nine participants were included. Greater synovial hypertrophy, power Doppler (PD) and meniscal extrusion scores were associated with worse NRS pain (B=0.92,95% confidence interval CI 0.25,1.58); B=0.73(95% CI 0.11,1.35) and B=1.01(95% CI 0.22,1.80). All greater ultrasound scores except for cartilage grade demonstrated significant associations with worse KOOS symptoms while only PD and meniscal extrusion were associated with worse KOOS pain. All ultrasound scores except for PD were significantly correlated with KLG. Ultrasound pathologies except for cartilage revealed moderate to good correlation with their MOAKS counterparts with ultrasound synovitis having the greatest correlation {0.69(95% CI 0.60, 0.78}.
Conclusion OMERACT ultrasound scores revealed significant associations with pain severity, KLG and MOAKS.