Trust that dread you're feeling.
Moving around with a cane inside requires lots of concentration and focus and it can be easy to trip and fall. And the kinds of small but constant movements you'd be making as a host, such as turns, talking to this person and that, can easily make your hip angry. You'd probably do a lot of bending and lifting--even if you try not to. And when a recovery hip gets angry, it throws a real tantrum afterwards--can be pain for days.
Much better would be for you to try to attend such a gathering set up and run by other people. That's much more reasonable. And the truth is, you want your friends and family to be waiting on you for early weeks of recovery--not you putting on a show for them.
I say trust that dread or fear you're feeling right now--that's your body's alarm system giving you a clear answer. Once you notify people that you will not be hosting the dinner because of your surgery, they'll all understand. And you'll accomplish something else. You will have alerted these folks to the surgery and they are likely to offer to run errands or bring food for you. Suggestion: take them up on those offers.