I agree with Karen, once the meds kick in she is going to feel better physically and you need to go back to potty training 101 to help her through this.

For constipation, you can add a spoonful of canned pumpkin to her food -- make sure you buy canned pumpkin, NOT pumpkin pie filling. The pie filling includes spices, some of which are toxic to dogs.

The meds for the UTI should help in about 3 days she will be feeling better. Make sure you keep up with the course of meds to the end, though, as the bacteria will still be present until she finishes those. She may be holding it in because with a UTI it hurts to 'go,' so the meds will address this.

Did the vet take any xrays for her back or hips? Or do you think that is going to just need some time to heal?

Once she is feeling well, prepare and keep a baggie of high value treats in the fridge, ready to go. I use cut up hot dog, cut up cracker barrel extra sharp cheddar cheese, and boiled boneless skinless chicken breast. These are SMALL; one hot dog makes about 80 treats. Keep a baggie of each in the fridge, and take one when you take her outside for walkies. Get excited about going out! Walk her (no standing still, no sitting in a chair) and only stop when she has to go. Once she finishes, have a PAWTY! Jump up and down, clap, dance, smile, sing, PRAISE HER, and treat, treat, TREAT! The treats are small, so you can give her 3 or more. If your dog and your neighbors are looking at you like you are nuts, you are doing it right; nothing else counts, lol.

You will be reconditioning her, desensitizing her, letting her learn that being outside, doing her business outside, is FUN!

Let us know your progress!