Review Question - QID 219475

A 58-year-old female presents to your office with complaints of knee pain for 6 weeks after an a fall while hiking. She reports the pain is localized to her medial joint line and is worse with twisting and pivoting activities. She also experiences symptoms of locking and catching at times. Radiographs demonstrate no significant joint space narrowing. MRI shows a complex posterior horn medial meniscus tear. Unfortunately she fails to improve with physical therapy and opts to undergo partial medial meniscectomy. She is doing well at her initial 2-week post-op visit but presents at 6-weeks with increasing pain over her medial joint line. She is not improving with physical therapy and a new MRI is ordered (Figures A & B). What is the most likely diagnosis?