Is there a natural cure/remedy for osteoarthritis that works?

ie one can tell within a week of starting the treatment that their condition is improving?

There is not a cure, but there is a natural protocol which will help:

Nutrients:
Boron - 3 mg daily (required for healthy bones)
Bromelain - as directed 3x daily (prostaglandin production)
Garlic - 2 capsules 3x daily (anti inflammatory)
Glucosamine sulfate - as directed (for bones, tendons, joint fluid)
Pantothenic acid (B-5) - 500-1000 mg daily (vital for adrenal gland)
Primrose oil or Salmon oil - as directed (anti inflammatory)
Sea cucumber - as directed (for joints and joint fluid)
Silica - as directed (for rebuilding of connective tissues)
Superoxide dimutase - as directed (antioxidant, protects joint fluid from free radicals.)
Vitamin C - 1000-3000 mg 3x daily with meals. (destroys free radicals)

Herbs:
Alfalfa, cat's claw, feverfew, ginger, cayenne, burdock root, devil's claw, nettle and yucca may all be helpful.

Dietary:
Consume foods containing sulfur -asparagus, eggs, garlic and onions.
Other good foods include green leafy vegetables, fresh vegetables, non-acidic fresh fruits,whole grains, oatmeal and brown rice.
Eat fresh pineapple daily. Bromelain is great at reducing inflammation.
Eat lots of fiber: flaxseeds, bran, and raw vegetables like celery and carrots.
Reduce the amount of fat in your diet. Do not consume dairy products or red meat. Avoid caffeine, citrus, paprika, salt, tobacco and sugar.
Avoid nightshade vegetables (peppers, eggplants, tomatoes, potatoes)
Do not take iron supplements, or multivitamins with iron. This has been linked to pain, swelling and joint destruction.

Get regular, moderate exercise.

There is no cure for osteoarthritis (OA), it represents the wear and tear of joints. The cartilage gets thinner and moth eaten, in worst case you have bone rubbing on bone.

Glucosamine and chondroiton have been shown definitively to have no effect at all on the progression of arthritis.

MSM is basically an organic solvent that has been reported to be helpful for the pain of OA, and touted by celebrities. Personally, I don't get my health information from celebrities. The evidence that it helps with pain is fairly weak. I'm not saying it doesn't work, but the studies done so far have been too small to make any conclusions. More study is needed. Whether or not MSM may help with the pain, it is NOT a cure. Plain acetominophen works quite well, and is safer.

MSM works fairly quickly.

It worked for Robert Culp and James Coburn. Coburn was at a point in which he could barely stand up. That's the reason we didn't see him in the movies for about 10 years. The MSM helped him in less than a week.