How do they accomplish the “zombie walking with a broken ankle” effect?

Question

Zombies are often shown dragging one foot behind them. The clip below shows an example from Shaun of the Dead (2004). You can see the zombie dragging its foot at 2:06.

How is this practical effect accomplished?

Answer 1

The easiest way to achieve that is to use an amputee. And yes, zombie-type movies use a lot of amputees as extras. It's just easier and cheaper than green-screening something like that. Attach a prosthetic, and they can hobble, crawl, get their legs bitten off, whatever you want with a little practical special effects.

If it was a main character played by an actor that you know is not an amputee, then they will use a green sock and create the amputation effect in post processing.