A 48-year-old male with left knee pain lasting for 9 months and swelling behind the knee was admitted to the orthopedics clinic. He stated that he had increased pain with standing and limited knee flexion. He had been receiving IV methotrexate (20 mg/2 mL 1 × 1 per week) and oral sulfasalazine (500 Mg 2 × 2 per day) for 3 months for the RA. During the physical examination, a large mass was observed behind the left knee, expanding to the proximal calf. The mass was immobile and soft when palpated. The range of motion (ROM) of the left knee was Fl/Ext 120/−10 degree.
McMurray and Patellar Ballottement tests were positive. Neurovascular examination of the left lower extremity was normal. Laboratory studies showed the following: ESR, 18 mm/h; CRP, 5 mm/dL; and WBC, 10.000. Minimal degenerative changes were observed at the medial plateau based on plain radiographs. Based on magnetic…
