Hi Loesje Shema. Whenever feeling pain while doing an exercise, please stop that exercise. Pain is not a good sign. I would suggest you consult with your doctor as to what moves are good for you and what moves you need to avoid.

Many of Sarah Kusch's videos are HIIT (high impact interval training). These types of workouts, especially with the impact, can be hard on knees if you already have bad knees. If in general you like her workouts, my recommendation is to try lower impact things during the moves that bother you. For example, can you substitute jumping jacks, skaters, lunges, or squats during her high impact moves? If you're keeping your heartrate elevated, you'll still be getting in a good workout.

Have you ever done any workouts by Kelly Lee? While still getting in a great workout, I find these routines to be a little easier on my body. I've attached a couple that I really like.

You may also consider some of Samantha Matthews's knee therapeutic videos.