Question category: Rheumatology
A 50 year old gentleman with a history of type 2 Diabetes Mellitus and hypertension and who is obese presents with a painful, swollen knee. An X-ray reveals chondrocalcinosis and a joint aspiration is performed and it reveals on microscopy numerous neutrophils and rhomboid-shaped crystals, which are weakly positive birefringent. Which of the following is the most likely diagnosis?