My mom is refusing to update her knee surgeon that she will have dental surgery next week. What are the dangers of withholding this info?

I as an RN don't see a problem here.
What concerns you specifically?

Unless your mom has underlying conditions there should not be a problem. If it were the other way around and she had a knee replacement and she refused to tell her oral surgeon that might present a problem.
I hate to jump on the bandwagon here but your mom is 69, in good general health and decisional. This is her choice to make. I am sure she is aware that there ight be complications. and if there are complications any travel plans will be postponed.

I don't get all the people who say to inform the surgeon, I can't imagine any of you would feel the same way if it was your kids interfering in your life. The woman is 69 and in good physical and mental health plus her dentist doesn't see this as a problem, I think this is her choice to make.

If its a tooth that is not seen like it the back, I would not do the root canal just have it pulled.

If she does not tell the surgeon, I would.

Appreciate all the feedback. Her initial total knee replacement surgery was postponed from December. Her dentist approved her for the knee replacement based on her assessment prior to December. The root canal issue just occurred after her tooth cracked this week. I don’t believe she’s giving me all the details. I try to ask clarifying questions because things don’t seem to add up. She was advised by a friend to take the delay(root canal) as a warning not to have the knee replacement surgery in February and is choosing to ignore it.

From everyones response 3 weeks seems to be the magic number but still risky. I pray for the best outcome for her. That’s really all I can do.

Thank you all for responding.

Other then alerting both doctors yourself about what mom is doing you may have to step back and let what happens, happen. Mom is making a choice that could have worse consequences than not going on her trip in June. And death is not the worse option here for her. There are things far worse than death resulting from infections and complications etc. She's an adult though so what else can you do?

The rule of thumb is that any dental work including root canal(which really isn't surgery by the way)should be done at least 3 weeks prior to any surgery, to reduce any risk of infections.
I guess if your mom is willing to take that risk then she will have to live with the consequences of her choices if God forbid something bad happens.

The American Dental Association and the American Association of orthopedic surgeons have differing views and the use of antibiotics and prosthetic body parts--at least they did several years ago.

My understanding is the danger exists--this was the prior orthopedic view not sure how up-to-date it is now-- if for instance, one has a knee replacement and then has dental surgery that results in an infection that can travel to the prosthetic body part.

From your post, it's not clear whether your mom is going to have knee replacement surgery or just knee surgery. In any case, yes she is cutting it close and an ongoing infection precludes any kind of surgery.

She's cutting it close... she should have the root canal no closer than 3 weeks before her knee surgery (is it a total knee replacement?) I had a total knee replacement this past August and from what I can remember and research 3 weeks seems to be the magic number. If she develops an infection, abscess or other problem from the dental work she really needs to disclose this to her surgeon. It's not worth the risks.

Dentist cleared her for what?

On antibiotics NOW for root canal?

Usually you need to take prophylactic antibiotics before knee surgery.