Hello @ladybug4joints, Welcome to Connect. It sounds like you are doing all the right things to help with Osteoarthritis. I have degenerative arthritis and osteopenia which wasn't on my radar for taking any actions to improve my health until the past few years. The CDC has some info on the risks that might give you a partial answer as to the why.

"What are the risk factors for OA?
Joint injury or overuse—Injury or overuse, such as knee bending and repetitive stress on a joint, can damage a joint and increase the risk of OA in that joint.
Age—The risk of developing OA increases with age.
Gender—Women are more likely to develop OA than men, especially after age 50.
Obesity—Extra weight puts more stress on joints, particularly weight-bearing joints like the hips and knees. This stress increases the risk of OA in that joint. Obesity may also have metabolic effects that increase the risk of OA.
Genetics—People who have family members with OA are more likely to develop OA. People who have hand OA are more likely to develop knee OA.
Race— Some Asian populations have lower risk for OA."
-- Osteoarthritis (OA): https://www.cdc.gov/arthritis/basics/osteoarthritis.htm

Hi ladybug4joints, I had my right knee replaced two years ago and just feeling back to normal with it. My left knee is bad but because of the rough surgery with the right one, along with the recuperation, etc, I don’t think that I will put myself through the left knee surgery unless is it *absolutely necessary*!!! After the right knee surgery, my right hip began to bother me so I went back to the surgeon for X-rays to my hip. He told me that both hips were “shot” and had a lot of arthritis. I asked him if people have all four joints replaced and he said that they do. However, I now do hip exercises, along with knee exercises almost every day and I am noticing a little bit of improvement. I have always been “a walker” but have slacked off and I can feel the difference. Your post encouraged me to get back to walking, so thank you!!! Like you, I am thin and pretty fit and I have no family history of replacements. Wishing you complete healing and all the best with your knee replacement in January!

Hi ladybug, and John,

Adding to your 2022 posts.
Regarding why multiple joints wear down, genetics versus wear and tear from an active life, I imagine that is hard to sort out, and I believe most agree being active is consistent with health as we age. As for walking a certain number of miles, perhaps that is variable, and hours per week might be considered alternatively, reference https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/walking
Before hip surgery I enjoyed a 3 mile hike over boulder fields, but flat trails may be safer now. 1 to 2 miles may be enough, plus I don't want to wear out the hip replacement components and need revision surgery in 10 years!

With your 4 joints replaced, have you been given any lifetime things to avoid? Have you been advised not to bend at the waist to touch the ground (i.e., greater than 120 degrees), avoid kneeling for more than 15 minutes, avoid low chairs, tennis or basketball? I have an acquaintance with multiple joints replaced who plays occasional tennis which I am surprised at. If I anticipate 20 or 30 years life expectancy I'd rather not wear out replacement components.

Best wishes, hope all is well in 2025!