You can do literally anything lol. Go out and groom your horse, sit in the grass with them and read a book, do some liberty. Anything you want. Just spend time with them.
I agree with what Zoe and Brittany have said! Lunging or free lunging is a good way to keep your horse active. You could get a stool to put in the middle and just sit as they go around if you couldn’t stand for that long either. Best of luck with your recovery!
I rode without stirrups when I injured my ankle. Or bareback. But that might not be the best idea, depends on what you did to it. Free lunge, chute jump, lunge or ground drive if you are allowed to walk. Liberty and trick training, obstacles, desensitive with tarps and pool noodles and whatnot, get creative!
Lunging your horse , walk him / her , feed them , talk with them , let them out in the area and free jump them or do flat work and liberty work