The main difference in Synvisc vs Supartz is that Synvisc is 20% synthetic. It adds to the molecular weight of the drug, however it has a side effect of severe pseudosepsis - basically painful inflamation of the knee. It is extremely painful and occurs in around 5% of the population in the first series, and then it jumps to 24.6% in the second series. This is widely known and is why they have been losing market share for 5 straight years. This is also documented in about 12-13 articles in bigtime medical journals, as well as in their own literature. The next time you get an injection ask to see the paperwork in the box, it's printed right there.
Supartz is the purest form of hyalurona available today with the mst active ingredient. It is also about half price and in over 155million injections there has never been one reported / documented case of severe pseudosepsis.
Just a little FYI.