I would think your urologist would have had some suggestions for you.

I know one person who had his prostate removed a few years ago and got a pump.

Both he and his wife seem pretty pleased with it.

Best source I've seen for post op ED info.  

http://www.franktalk.org/Enter.php?redirect=/index.php

We aren't going to care if you're ONLY 50 something and I'm pretty sure you might get some recommendations there too.

Hi TomDoc69.  I also had this surgery about 6 months ago and have had problems.  None of the oral medications were doing the trick and my Dr. suggested injection therapy which I've been using for a few months.  This works well.  It's a bit freaky putting a needle in your johnson but it's very thin and I would call it discomfort not pain.  It takes some experiemntation to dial in the dosage.  It is very possible to have a raging hard on that just won't go down.  Depending on your partner that could be good or bad.  Either way, if untreated it causes permanent damage but sudafed works great, I've had no problems.  I say give this a go before you resort to the pump.  I'm happy with it.  Of course, I'd be happier if I was 25 and my dick got hard when the wind blew but that won't happen.  Hang in there, you're among friends.

Try something new like...

Have you ever explored tantra?
there are many techniques that help to intensify and deep the energetic exchange that occurs during an erotic experience...sometimes we must alter our perspective to experience something new and greater than ever before

A friend was active in the hobby before getting prostate cancer.  Now he can get horny but not erect and wants to see a provider.  Should he tell the provider about his problem before seeing her?  It seems like a difficult topic to approach since many providers don't want to discuss details before the session, especially if you have not seen them before.  My instinct tells me that older providers may be better to help him sine they have the experience.