My doctor said I have early arthritis in my knees. Doing any sort of squat hurts my knees. What exercises do you recommend to work out my legs?

I know it can be difficult to feel limited this way. There are still so many exercises that you can do to keep your legs strong and functional - finding the ones you can move through without pain, or minimal pain, is going to be the key. Deadlifts, sumo deadlifts, Romanian deadlifts, leg extensions, hamstring curls, kneeling squats are just a few that come to mind that doesn't involve a ton of knee activity. Definitely substitute any exercises that do not work for you for ones that do! You've got this!