The course of ultrasonographic abnormalities in knee osteoarthritis: 1 year follow up

Imaging of (peri)articular structures and inflammation with Ultrasonography (US) during the course of osteoarthritis (OA) might contribute to knowledge about early diagnosis of OA, prognosis and possibly the effect of disease modifying drugs. Our goal was to identify the prevalence of distinct patterns (stable vs fluctuating) in a set of US features in a cohort of patients receiving standard multimodal treatment for knee OA at T = 0, T = 3 months and T = 12 months.

This was a prospective, explorative study including 55 patients fulfilling the American College of Rheumatology clinical criteria for knee OA. Six US features were investigated including: effusion, synovial proliferation, infrapatellar bursitis, meniscal protrusion, Baker's cyst and cartilage thickness at three time points during 1 year. A composite inflammatory score was composed. Overall prevalence was assessed as well as individual patterns which were appointed as stable or unstable.

Inflammation like effusion and synovial hypertrophy does occur in over 40% of patients at some time in the year of follow up and shows a fluctuating pattern. Meniscal protrusion and Baker's cyst however are more stable features.

Our study gives insight in the prevalence and course of US abnormalities in patients with knee OA and contributes to the knowledge on the possible role of this imaging modality in research.