Woofgang "I would be amazed (and a little worried) if any kind of potion applied to the skin could not only make its way into the blood stream, but also through the muscles and connective tissue, then through the joint"
Locally acting non-steroidal anti-inflammatory (NSAIDS) gels and creams can do just that, they penetrate to a limited degree into the skin and joints (without taking bacteria with them). Depending on the formulation reasonable levels of the drug can be found in the joints, and much lower levels in the bloodstream. They are only of use when the joint is near the surface - knee or wrist for example - and would not be of use where there is generalised osteoarthritis.
The most recent Cochrane database analysis 34 studies 7,688 patients, suggest for osteoarthritis of the hand or knee they are effective.
http://summaries.cochrane.org/CD007400/topical-non-steroidal-anti-inflammatory-drugs-for-chronic-musculoskeletal-pain-in-adults
To get back to Flexiseq, it does not contain a drug but uses much the same delivery system to penetrate the skin, so again would only be useful for joints such as knee and hand. In trials it seems to go under the name of TDT 064 so is hard to find on Google
http://www.ncbi.nlm.nih.gov/pubmed/24164189
Arthritis UK is generally a very good site, it gives details of the trial, and suggests it is early days yet for Flexiseq. There is as yet only one major trial, so I agree perhaps a little early to be selling it.