“I’ve got bad knees. My mom had bad knees. Her mom had bad knees.”
I hear some version of this most weeks, and it’s usually said with a shrug, because the person has already decided the matter is settled. It generally isn’t.
There are inherited conditions that genuinely affect joints and connective tissue, and they’re real and they matter. But a family in which everyone’s knees hurt is more often a family that moves the same way, wears similar shoes, works similar jobs, and shares a belief about what happens to knees after forty. Those things travel through households just as reliably as genes do, and they’re considerably easier to change.
My own version of this
The women in my family have long toes, and my mother grew up expecting hammer toes because her mother had them. I inherited that expectation along with the feet, and for a while I could see the curling beginning.
Then I went to chiropractic school and learned how a foot actually works — which structures do what, which can be isolated, and how to strengthen and mobilize them. I reversed the curling. I also have naturally flat arches, and by working on the strength of my feet I improved the arch that’s there.
I’m not describing a miracle. I’m describing what happens when someone stops treating a body part as a fixed inheritance and starts training it.
Why the belief itself does damage
Expectation shapes attention, and attention shapes behavior. If you’ve decided your knees are bad, you move to protect them, you stop doing the things that would load them usefully, and the surrounding muscle gets weaker — which produces exactly the knees you were expecting.
The same pattern shows up with hips, shoulders, and with the very large number of people convinced they have sciatica who don’t.
What I’d actually look at
Whether the joint has the range it should. Which muscles around it are tight, which have gone quiet, and what that combination is doing to how the joint tracks. What your feet are doing, since a knee sits between a hip and an ankle and takes instructions from both. And what your day asks of you, because eight hours of one position is a training program whether you intended it to be or not.
None of that is genetic. All of it is workable.