Since what seems like forever, (at least twenty years) my knees have been a burden. Twelve years ago I had bakers cysts in each of them, and had an atheroscopy on both which helped the twanging of a muscle over the lump each time I took a step, but never really fixed the pains I was having, and still have. A couple of months ago I reduced my intake of protein right down which helped no end in the sharp glass shards in the joint type pain I was having, but alas I feel the damage has already been done, and the knees are shot, though I must say there is no swelling at all on the one that is most painful and only a little 'puffiness' over the knee cap on the least painful knee, unless I kneel when it hurts more. So back to my question, How bad should it be before a replacement is warranted? I would love to be able to run again, but haven't for over twenty years. (I am 59 tall and slim) and I am sure the Doctors do not realise how much pain I am in, just because I look like I am fit and well!!