Are ultrasonographic signs of inflammation predictors for response to intra-articular glucocorticoids in knee osteoarthritis?

OBJECTIVES

To investigate the predictive value of ultrasound (US) characteristics for the effect of intra-articular glucocorticoids in knee osteoarthritis (OA).

METHODS

In this prospective cohort study, 62 patients with symptomatic knee OA (clinical knee OA criteria, pain>4 on a Numerical Rating Scale (NRS; 0-10)) received an intra-articular glucocorticoid injection (40 mg triamcinolone acetonide). Patients with NRS pain ≤4 at 4 weeks were defined as responders. On inclusion, demographics, clinical data (body mass index, local swelling) knee x-rays and knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire were collected. Six US features were assessed including: effusion, synovial hypertrophy, Baker's cyst, infrapatellar bursitis, meniscal protrusion and cartilage thickness. Stepwise multiple logistic regression analyses with forward selection were conducted to identify possible predictors.

RESULTS

At 4 weeks, 42% of the study participants reached a NRS ≤4; an effect comparable to existing literature. Regression analyses showed that patients who used analgesics at baseline were less likely to have a good response. The small proportion of patients with infrapatellar bursitis was more likely to respond to the injection.

CONCLUSIONS

No patient, disease or US characteristic of inflammation, turned out to be a reliable and clinically meaningful predictor for the effect of intra-articular glucocorticoids after four weeks in knee OA.