But you offered

[NOVA Lady]

I think a lot of people like to look and feel generous but when push comes to shove do not actually want to do anything for you.

I don't make an offer for help unless I can come through, but so many people will offhandly say "Oh let me know if there is anything I can do to help!" with no intention of doing anything and just banking on it being unlikely that you will take them off on it.

But whether they expect it or not...if someone offers their help it is not rude for you to take them up on it if you thought the offer was sincere.

[Lisbeth]

I have to say that it's entirely possible that it's just random chance rather than flakiness or favor-currying that led to this.  I've had to help someone move furniture at the last minute because six people had legitimate emergencies come up all at once, so although it's unlikely it's certainly possible.  Unless these friends have a history of flaking out (and from your description of them it seems like they've been reliable in the past as a help network), I'd just chalk it up to bad luck.  In answer to your question, you didn't commit any rudeness calling people in on their offers to help you as a backup when it became necessary to find a backup.

Virg

Pod.  By the way, good luck with your surgery-I'm glad you were able to find someone to help you.

[Itza]

I find myself in a fairly awkward situation.

I have to have a minor outpatient surgery that will require general anesthesia in a few weeks. I arranged the date after consulting with a friend who agreed to drive me to and from the procedure and keep an eye on me for the rest of the day. Several other friends offered to help in anyway possible, especially if plans fell through.

Well, original friend got a job offer. I shared my congrats, then started calling the other people who offered to help. People either haven't called back or said awkwardly that they already had plans for the day. One woman offered to take me back to her house, but I'd really rather be in my own home.

Is it weird or in any way rude to take people up on their offer to help? Or are my friends really flaky?

In my unfortunate experience, the offer is the help. You're not actually meant to take people up on it 

[Lynn2000]

I'm glad the OP found someone to help her. From what she's posted, it does sound like her friends were a little flaky--it sounds like they offered to help in that specific way on that specific day, in case the original plans fell through, and then when the original plans DID fall through only a couple days later, suddenly they were all busy. Which, on the surface, to me gives the impression that they weren't serious about their offers at all. 

When people make much more general offers of help, though, I don't think they can be expected to drop their plans and assist whenever, whatever. A couple years ago a friend of mine had major surgery and needed weeks of recuperation time, when she had trouble getting around on her own. A lot of her friends had said, "Just let me know if you need any help!" Then she would call someone at 2pm on a weekday and ask them to drive to her house right then, from their work, and help her get into and out of the shower. And they'd say no, and she'd be disgusted with them and think they weren't being good friends. Granted, this is kind of extreme, but I'd never seen the situation from the other side until that incident.

But just to reiterate, I don't think the OP did anything rude at all in this situation.

[sevenday]

I don't think the OP did anything rude either.  The friends do come off as a bit flaky, but I don't think they were necessarily rude either.  Disappointing, but not rude... and I'm very happy to hear the OP found someone who could help!  A good friend indeed to make such necessary arrangements to help out when needed.