Ultrasound-Guided Aspiration and Corticosteroid Injection of Baker's Cysts in Knee Osteoarthritis A Prospective Observational Study

Objective: To determine the effect on pain, function, and ultrasonographic findings of ultrasonography-guided Baker's cyst aspiration followed by corticosteroid injection in a group of patients with Baker's cyst secondary to knee osteoarthritis. Design: Prospective observational study. Results: Twenty-six subjects participated in this study. Clinical and instrumental evaluations were performed at baseline (T0), 1 wk (T1), and 4 wks (T2) after procedure. Mean Visual Analog Scale scores significantly dropped after the procedure (T0 = 6.2 [1.2]; T1 = 4.48 [1.5]; T2 = 4.32 [1.3]; T0 vs. T1 and P < 0.0001). A significant difference between preprocedure and postprocedure Western Ontario and McMaster Universities scores was found for pain (P < 0.0001) but not for joint stiffness (P = 0.7239) and disability (P = 0.6318). Ultrasonographic evaluation showed a significant reduction for both axial (P = 0.006) and sagittal (P = 0.01) areas of Baker's cyst, but no correlation was found between pain relief and Baker's cyst volume reduction. Conclusions: Cyst aspiration with corticosteroid injection give pain relief and cyst volume reduction in patients with Baker's cyst and concomitant knee osteoarthritis. However, when compared with current literature, our results are similar to those obtained with intra-articular knee corticosteroid injection.