Our Challenger is a US Army Infantry veteran who has gout in both knees that gets severe at times. When it flares up he cannot walk and has been on crutches a month now. He states that a hot shower makes his knees feel better and when the hot water is on the joint, the pain goes away. 

There are knee braces on the market that heat up the knee with electricity or infrared technology, but they are not water-based.  He has tried hot pads on his knees, but that does not work for him.