My grandmother recently had partial hip replacement. She is doing very well physically, however she is not recognizing her own home.

Anesthesia commonly effects cognition in the elderly. Sometimes they do not recover, in my mom's case she continued to decline. In her husband's case he was loopy for a couple of months and fully recovered.

Check out this article

https://www.agingcare.com/articles/how-general-anesthesia-affects-elders-mind-160100.htm

Katriggs, at 91 what can be happening is she is in cognitive decline. I strongly recommend she has all her legal ducks in a row, and it would be fantastic if you could find out if she does. If she has not assigned anyone as her durable PoA, it will make legally helping her needlessly more difficult. She needs to get this into place before she has an actual cognitive exam, before it gets into her medical records, if at all possible. A PoA signed after a dementia diagnosis can be contested.

Your husband's reality now is that gramma can't be alone. We were trying to care for my MIL in her home until we discovered she wasn't remembering to eat. Food was rotting in her fridge. She couldn't remember how to use the microwave. We'd call her every day and ask what she ate and she'd give us a detailed account, only to go to her house the next day and find no dirty dishes, no food containers in the trash. She had to go to AL to keep her protected and socially engaged.

Right now you and your husband only have seen the tip of her cognitive iceberg. You and he should make a trip up there to have a discussion with her. Start there and see where it goes. It needs to be gentle and compassionate. She may resist any change or help but this doesn't mean she is ok. You cannot be expected to keep making a 5-hr drive because she won't leave her house (you know, the one she no longer recognizes). Do not take her into your home to care for her (please read some of the thousands of posts on this forum under Caregiver Burnout). I wish you and your family great success in helping her in a compassionate, realistic way!

Your profile says grandmom has dementia. Then u say she hasn't been diagnosed. Did you see signs of decline before the surgery?

Breaking a hip is very serious in the elderly. The anesthesia can cause Dementia type symptoms. If you have Dementia, it can cause further decline. Being in the hospital and then rehab can cause some confusion. There's a name for it, just can't remember it.
It can tak the anesthesia a while to wear off. She could also have a UTI that causes confusion.You need to bring up this change to her PCP.

Delirium.

Here's one google definition but please get proper medical advice.

'Delirium is a term meaning “sudden confusion.” It refers to a sudden change in mental function. ... Post-operative delirium is delirium that happens after an older adult has an operation (surgery) and is the most commonpost-operative complication in older adults'.

After hip surgery in elderly patients it is VERY common. Your Grandmother will need supervision until it passes. Can last weeks & be off & on.
Sometimes if there was some mild cognitive decline, this may become the 'new normal'. Keep her supervised, either at your home or someone moves in to hers (if possible). She will be a huge falls risk among other dangers.

I'm glad she has recovered physically but you will have to watch & wait I'm afraid. Good luck.

Have her checked for Urinary Infection and rule that out first. Check meds for side effects. If nothing shows up with these, there is also a chance her body has not completely recovered from anesthesia -- however -- you said there were a couple of issues prior to surgery.
Maybe watch and wait. It may well be a true mental decline and important to watch for things such as leaving pots on stove to burn to identify if she needs additional help in the house or someone to be with her in the home.

How recent was the surgery? Many people even young people go through a period as long as a week after any surgery with a lot of anesthesia followed by narcotics in a serious brain fog. This usually gradually dissipates. However, in older people , if the narcotic is continued for about 2 weeks after surgery, they do not seem to fully recover mentally until the narcotic is ceased.Both anesthesia and or narcotics have a much stronger and longer lasting effect on an older person.Hopefully the pain will diminish so the narcotic can be stopped.Then, after no narcotic for about a week, a mentally normal state may return.If narcotics are continued even in small doses, the patient may never recover completely mentally. It is a difficult challenge controlling pain without doing mental damage.I was very blessed to have a wise, caring, and competent surgeon for my knee replacements at age 78. I was in a brain fog untill about 2 weeks after my surgery. I gradually recovered completely. However, I was able to quit vicodin onlt 6 days after surgery.I also was blessed with a wonderful therapist who guided me carefully throughcarefully planned and pain free activities every other day for 4 weekd.I am so very grateful to have been healed mentally and physically. We all need to stay away from vicodin and or any other brain altering substances. However,they are necessary for serious surgery.I am now 86, happy, healthy, pain free, and med free. i pray your loved one will recover completely.

My husband had lithotripsy in 2006 and again in 2007. He did not come out of the anesthesia "right" in either case. He was never the same again. I noticed it immediately, but thought time would take care of it. It didn't. Nobody seemed to notice but me. By 2008 he couldn't pass a simple memory test. He was 62 years old at the time. I took care of him until five months ago. He's now 73, in a memory facility, and is in acute end-stage Alzheimer's with a brain that swells. He is now aggressive, dangerous, and attacks the staff. There is no doubt in my mind the anesthesia caused it. Prior to the anesthesia, he had NO issues of any kind.

Imho, anesthesia COULD be the reason for her disorientation.

It could be that the stress of the surgery along with the anaesthesia has affected your grandmother's cognitive status. Plus she was moved to different locations along the way. I would give her a little time for her to adjust in her own home to see if the situation improves. If it does not improve, I would suggest a cognitive evaluation by a neuropsychologist or a geriatric psychiatrist. Good luck.

one month 2 weeks... and she is not normal... Get her back in and have a brain scan.. Seriously.. HAVE HER BRAIN CHECKED...
Did she have a stroke in that time frame? Seizure? or are there more signs of dementia from this operation?