She was fine prior to surgery.Since surgery she has quickly developed dementia which is advancing quickly. Will her mental capacity improve over a period of time? It has been 3 months since surgery.
The rule of thumb I've heard is that for every hour a person is "under", count on a month of recovery time needed. Has she been seen by a neurologist? Do her docs feel that there was some dementia prior to surgery that was worsened? Have they checked for stroke?
I agree with Babalou regarding the recovery time for every hour someone is "under". One can be in a fog for a month or more, plus add advance age and it could take longer.
Rehab recovery is very painful, thus pain meds could also mess with one's thinking. I remember last year taking a morphine type pain pill for a broken bone and never took a second pill, I rather had dealt with the pain than deal with the mental capacity side effects.
My FIL had gallbladder surgery when he was 89 and immediately after surgery he lost his mind. I'm talking thinking balloons were people staring at him, not knowing relatives (it didn't help that we wore yellow hazmat suits because he also developed C. diff.) and not even remembering he'd just had surgery or why. The doctors explained that with elderly patients, particularly if they already have early dementia, which FIL did have, it's not uncommon for surgery/anesthesia to cause this kind of extreme confusion. FIL was like this throughout his two week hospital stay and, to a lesser degree, for two months at home where we were taking care of him. He did get better, but had good and bad days for quite a while. We were afraid he would never get his wits back. He mostly did. That his dementia has since gotten worse, we're not blaming on the surgery. As I said, he had it to begin with, just not like that! If your mother doesn't have dementia, she will still have lingering effects from anesthesia for a couple of months, plus the effects of any pain meds. Surgery is tougher on older bodies. Prayers that she has excellent new knees and will enjoy getting around better.
So sorry to hear about your MIL. My Dad had quadruple bypass surgery and suffered cognitive impairment as a result. Apparently this is not uncommon in elderly and sometimes people not too old. After a long recovery in ICU and a few weeks in Rehab we were told he would not regain his lost cognitive skills. I have seen this called Pump Brain, it is not something the doctors every mentioned. Unfortunately my Dad passed 2 months after the surgery. I know of another woman who had the same surgery and was fine after it. Hopefully your MIL will recover . Good luck.
Rehab recovery is very painful, thus pain meds could also mess with one's thinking. I remember last year taking a morphine type pain pill for a broken bone and never took a second pill, I rather had dealt with the pain than deal with the mental capacity side effects.