After my mom’s hip surgery she is acting disoriented and confused. Should I be worried about her behavior?

I'm so sorry! It's unfortunate to say the least, but this is not uncommon. Some people get better, others do not.
My dad didn't have dementia when he went into the hospital for surgery, but came out with it. There are many theories about this situation that run from anesthetics being used to the trauma of hospitalization. Often, there is no way to tell, though research is being done.
A broken hip is also a major trauma to the body, and many people don't fully recover from that blow. You should stay in contact with her doctor in case more can be done, but be prepared for her to go in either direction. She may get better, or she may continue to get worse as time goes on. In other words, the trauma may have sent her "ahead" in her dementia journey. Again, I do know your pain. My condolences.
Take care,
Carol

The same happened to my mom. She broke her hip sweeping her porch. At the time she was independent & lived alone at 93! After recovery & rehab she went home and we had a sitter with her. She thought she could walk alone and got up to go to the bathroom, fell and broke her femur, same leg as the hip surgery 4 weeks earlier. She recovered from the surgery, quite frankly I did not think she would survive the second surgery! But she has gradually been more out of touch. She does not want to try to walk and the physical therapy seems too much for her. Maybe this is typical but now she has to have 24 hr care and even though she eats well, she is no longer "herself". She gets very confused and then will have lots of anxiety for which she has to take Xanax. It is very sad and difficult to see her go down so quickly. I have great empathy for anyone in this situation.

Unless your mom has had surgery in the last 24 hours the anesthesia has worn off. And like Carol said, breaking a hip at her age is catastrophic. Often it's the beginning of the end.

If your mom is still fuzzy and confused I'm not sure she'll bounce back at this point.

Yes, you should have been warned about the effects of anesthesia on elderly people.