Depends on your age/weight and why it is sore, you bumped it, twisted it, arthritis ? an apple-cider-vinegar compress for 20min, may help, but maybe not. Believe it or not, I was told this by a certified nutritionist , large amounts of vit-C , 3-5 grams a week, can help rebuild cartilege in knee, so-called experts say no....my neighbor had many surgeries which can't be undone. But we still don't know how you injured it ? Eh?