Study of Nonsteroidal Anti-inflammatory Drugs in People With Painful Knee Osteoarthritis

Once screened and found eligible, participants will be entered into an initial blinded 2-week treatment period of either naproxen or placebo and then entered into an open washout period of 2 weeks. At the end of this washout, participants will then receive either naproxen or placebo for a further 2 week period followed again by a 2 week washout. This sequence will then be repeated (total of 4 treatment periods) such that all participants receive naproxen for 2 treatment periods and placebo for 2 treatment periods. The order of treatment will be randomized.