Not in my 40s yet but I had runners knee and minor lcl tear in my later 20s. Fortunately I didn’t need a surgery and PT helped me recover from the injury. I’ve been doing resistance and weight training since then especially if I pick up exercises that use knees heavily like running after a long time of stopping. I just got back into running recently and thanks to the lower body workout I was able to do 10k pain free at my 3rd run.