You can't "just walk", you need to retrain and build up her confidence. Itis going to take time and consistency in training. Start by putting her leash on her and playing in the front yard. After she is comfortable with that use treat6s to coax her out on the side walk. After she is comfortable with that use the treats to get her to the corner. And then after she is comfortable with that the next block, and so forth.
My dog got hit by a car 2 years ago when she was a puppy, now she won't go for walks in my neighborhood, how can I just walk out of the house and take her for a walk again?
When she wants to go for a walk she will if she doesn't take just means she might be scared or she just doesn't want to.
It's going to take some time and a lot of patience. Go slow and easy, never push her into something she doesn't want to do. That will just cause more stress for her. If you don't have any luck doing it yourself then try an animal behaviorist. Sometimes trauma like that requires a professional.
Have you talken to your Vet here about this as there may be a medical reason for this like severe arthritis has set in or maybe something didn't heal as it was suppose to. Your Vet may have some ideas to help here so start there first. Good luck