i bought the good heel cups in a hospital pharmacy and they made my feet worse. anything that seems to change the pronation of my foot makes my feet unhappy.
i've been able to avoid cortisone injections in my feet, but i've had 3 cortisone injections elsewhere and they've been nothing short of miraculous.
so if it comes to that, they should help, i'd imagine.
have you had cortisone injections elsewhere? did they help you?
as for the second kind of injection, haven't heard of that.....
i've heard of prolotherapy where they inject saline solution,
and the solution is supposed to allow the tendons to heal themselves
and get stronger:
http://www.prolotherapy.com/but i have no idea if its scientifically well founded or pseudoscience......
no idea if it works or is quackery.
to avoid any kind of injection to my feet, when they've been really bad, i do a lot of contrast baths for the feet (alternating hot and cold water, very helpful), use a heavy dose of epsom salt (magnesium salt, don't know if that is helpful), try to stay off my feet as much as possible, wear the "boots" to bed to keep my feet from relaxing (don't know how helpful that's been to me, but others find that very helpful), stretch my calves a lot (very helpful), and strengthen my feet with excercise (also very helpful, but i must do it carefully or i can pull the tendon-ligament Plantar Fascia or tendon-ligament on the top of the foot if not careful). hope this helps.
sue
