A commonly encountered referral in many Physiotherapy clinics is 'OA knee...do the needful This was one such referral. An elderly patient with a longstanding history of bilateral knee pain, but a recent exacerbation in her left knee. This was causing significant discomfort and functional limitations. On examination there was a marked effusion , which was noticeably tender proximal to the knee. The effusion also felt slightly firmer than normal. Here is one of the images demonstrating the area of calcification within the effusion.