@hellothere If you have access to a treadmill that is better than walking outdoors on pavement because there is less impact on your knee. If you are walking on pavement make sure then that you have very good cushioning walking shoes/sneakers to absorb the impact. Initially, I definitely found that using a treadmill vs walking outdoors made a big difference, but now I am fine walking outdoors. My orthro most highly recommended water jogging, and pedaling on the recumbent bike -- both are very low impact.
I personally found the memory foam in Sketchers sneakers to be excellent. I actually purchased mine in Marshall's, on sale, for somewhere in the $35 price range, so you don't have to go into a shoe that costs upwards of $100. I did that and found when I wore them my shins hurt more than they did in the reasonably priced Sketchers.
JK