hi Katharine,
you may find some information about glucosamine from the journal, Physical Medicine and Rehabilitation- Clinics of North America, August 1999, The topic is complementary therapies in physical medicneand rehabilitation.
there are charts for placebo controlled clinical trials for glucosamine and condroidin and 2 pages of brief info
i hope it works or can be a start for some more things which u can find from the refrences...
good luck