Efficacy and Safety of Musculoskeletal Ultrasound Guided Aspiration and Intra-Lesional Corticosteroids Injection of Ruptured Baker's Cyst: A Retrospective Observational Study

Ultrasound for suspected Baker's cyst: A test of limited clinical value?

Introduction

Patients with posterior knee swellings are commonly encountered in clinical practice with the vast majority referred for an ultrasound scan to assess for a clinically suspected Baker's cyst.

Aims

Our aim was to determine the incidence of different pathologies in patients investigated for a posterior knee swelling of a clinically suspected Baker's cyst using ultrasound. We also wanted to investigate the incidence of significant pathologies in the popliteal fossa to assess whether the ultrasound scan findings influenced patient management.

Methodology

Retrospective analysis was performed on all patients who underwent an ultrasound scan for a suspected Baker's cyst or posterior knee swelling at our institution, between January 2017 and December 2018. Patient demographics, ultrasound findings, further imaging investigations and histopathology were recorded. Patient records were followed up for a minimum period of 3 years after ultrasound.

Results

A total of 680 patients had a posterior knee ultrasound scan. Of that, 51% (347/680) had a Baker's cyst and 40% (273/680) had a normal ultrasound scan. Sixty (9%) patients had other abnormalities identified within the popliteal fossa. Four patients had significant findings on ultrasound that required a change of management. No malignancies identified.

Conclusion

This study confirms the high incidence of Baker's cysts in patients presenting with a posterior knee swelling. In the absence of red flag symptoms, ultrasound of the posterior knee for a clinically suspected Baker's cyst is of limited clinical value.

Baker's Cyst

The authors present a case of a Baker's cyst in the right leg of an 86-year-old woman, whose presentation was more typical for a deep venous thrombosis. Both conditions have inflammation and acute calf pain. The clinical manifestations, imaging findings, and treatment of this common emergency department presentation are discussed.

Ruptured Baker's Cyst: A Diagnostic Dilemma

A ruptured Baker's cyst is a rare presentation and may mimic deep vein thrombosis (DVT) or acute thrombophlebitis. In rare cases, it may present with infection or compartment syndrome. We present our experience related to a case of a ruptured Baker's cyst and its management. A 54-year-old female presented to us with knee pain, which was initially managed conservatively. After six weeks, she came to us with severe pain and swelling in her left calf and foot. It was an acute presentation and DVT was suspected initially. Ultrasound color Doppler showed no DVT and then MRI revealed it to be a ruptured Baker's cyst. The patient was subsequently managed conservatively and her condition improved in 12 weeks of follow-up. A high index of suspicion and knowledge is required to diagnose a ruptured Baker's cyst, and most of the patients respond well to conservative management.