Ultrasound-Guided Aspiration of Symptomatic Baker’s Cysts Reduces Pain

Aspiration of Baker’s cysts under ultrasound and fluoroscopic guidance followed by a therapeutic injection of methylprednisolone and bupivacaine reduces symptoms in most patients, according to a study presented here at the 2017 Annual European Congress of Radiology (ECR).

Judita Laurinkiene, MD, University Hospital, Waterford, Ireland, and colleagues reviewed outcomes in 14 consecutive patients who underwent 17 procedures followed by therapeutic injection over a recent 35-month period following referral from the orthopaedic service.

All patients had presented with knee pain, and some had complained of a sensation of “fullness” behind their knee. Swelling was palpable in most of them.

The presence of a Baker’s cyst was demonstrated on magnetic resonance imaging (MRI) performed to further investigate their knee pain.

Puncture and aspiration was performed with a 10-cm 5 Fr sheathed needle in all patients, yielding an average volume of 16.07 mls. Communication with the knee joint was demonstrated in only 3 of 17 procedures, despite the characteristic “tail” being visible on ultrasound in most of them.

At a mean follow-up of 11.7 months, Visual Analogue Scale scores had decreased from 5.7 to 0 for a mean duration of 5.96 months. After this period, patients reported a gradual return of an ache. However, the ache was not as severe as it was before treatment which, in some cases, had caused sleep disruption.

Two patients remained off all pain medications for 12 months. The swelling remained resolved in 11 patients overall.

Two of the 3 patients with complex cysts had prolonged, complete relief of the pain at the cyst site, with some ongoing knee joint pain in 1 and with return of slight swelling in the other. The third patient experienced 1 month of relief followed by a return of less severe pain compared with pre-procedure; this patient had ongoing issues with patellar maltracking.

Dr. Laurinkiene cautioned that the study was retrospective and had no comparison group. Additional limitations include the small number of patients and procedures and limited follow-up.

Despite these limitations, the findings show that the treatment had a durable effect on symptoms, with “the combination of decompression via aspiration and the anti-inflammatory effect of steroids working synergistically.”

The European Congress of Radiology is sponsored by the European Society for Radiology.