In terms of the Deca joints issue, Deca is actually anti-inflammatory via it's effects on the cellular arm of the immune system. It's not the water retention, as plenty of other steroids such as Anadrol have much higher water retention. If you want more info, check out this thread:
http://www.cuttingedgemuscle.com/For...?s=&threadid=8
In terms of tendon support, some steroids like Deca will make them stronger but more brittle. I believe Winstrol helps flexibility as well, but i'd have to do further research. Equipoise has a good reputation for tendons, as it boosts collagen synthesis, which in turn helps build up tendons and connective tissue.