Effects of Sono-feedback during aspiration of Baker’s cysts: A controlled clinical trial

Objective: To determine whether (diagnostic and interventional) ultrasound imaging can be used to provide visual feedback affecting treatment outcome (pain and disability). Design: Controlled clinical trial. Subjects: A total of 52 patients with (ultrasonographically confirmed) symptomatic Baker’s cysts were enrolled. Methods: The cysts were drained under ultrasound guidance and, if necessary, corticosteroid injections were given on the follow-up visit. In group I (n = 26) the patients did not observe the procedures on the ultrasound (US) screen. In group II (n = 26) the US images/videos were shown and explained to the patients. The patients were included in one of the groups consecutively, unless they refused the protocol of that group. Treatment outcome was assessed via US measurements, aspirate volumes, visual analogue scale (VAS) (knee pain, procedure discomfort), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Rauschning-Lindgren Classification (RLC), Kellgren–Lawrence grading scale, Hospital Anxiety and Depression Scale, and paracetamol intake. Results: The 2 groups were similar regarding US measurements, aspirate volume and paracetamol use (p-values > 0.05). In both groups all VAS (p < 0.001) and WOMAC (p < 0.05) scores decreased after treatment. Although initial VAS and WOMAC scores were similar between the groups, all VAS/WOMAC scores, except VAS-2, WOMAC-2 pain, and WOMAC-3 stiffness, were significantly lower in group II (all p < 0.05). Initial RLC scores were similar between the groups; however, group II had significantly lower scores at visits 2 and 3. Conclusion: In patients with Baker’s cysts (diagnostic/interventional) US imaging can be used as a simple means of visual biofeedback, favourably affecting the treatment outcome (pain and disability).