whether glucosamine and chondroitin (Osteo Bi-Flex, etc) are effective for arthritis

There's continued debate about whether glucosamine and chondroitin (Osteo Bi-Flex, etc) are effective for arthritis.

Some early studies suggested that glucosamine reduces knee pain and slows progression of osteoarthritis.

Now a large study says that glucosamine plus chondroitin is NOT very effective for knee pain...and it DOESN'T slow progression.