A case of ruptured infrapatellar bursa sac with Baker's cyst

A 40-year-old female arrived with persistent posterior right knee pain, swelling in the popliteal, infrapatellar, anterior calf areas and difficulty walking due to joint stiffness. Multiple hypoechoic collections with internal echoes and debris were discovered in the anterior calf region using ultrasound imaging, which extended from a thick-walled infrapatellar hypoechoic collection with peripheral vascularity. A significant popliteal fossa cyst of comparable appearance was also observed. The results were consistent with a ruptured infrapatellar bursa sac and a popliteal fossa (Baker's cyst). The patient received conservative treatment with anti-inflammatory drugs, leading to the resolution of symptoms after a period of 6 weeks. For patients with more complex cysts, procedures like aspiration and corticosteroid injections under ultrasound guidance may be necessary. Recognizing the condition and using ultrasound for diagnosis and management can lead to successful outcomes.