Can you please tell me about a supartz (hyaluronic acid) injection treatment?

Supartz (hyaluronic acid): This a gel type injection for arthritis either in 3 or 5 weekly treatments. It is supposed to boost the normal fluid content in the knee to help with pain. There is anecdotal evidence that it helps. It is not covered by all insurances and may require preauthorization for treatment. It is certainly an option if nothing else has helped like exercises, nsaids or cortisone injection.