Many of us older pickleballers have fragile knees, or knees that are prone to pain. There are some strategies for you.
It is not necessary to run to the non-volley line after receiving the serve or return-of-serve. As soon as you can, start a steady walk up to the kitchen line. Start right away, and don’t stop to smell the flowers along the way. Unless you are in top-level play, you’ll get there in plenty of time.
Practice your underhand strokes. While forehands and even backhands are easier for most players to control than underhands, you can still do a fine job. Underhands work best if executed at your side, not directly in front of your body, so you have room to swing, and so your arm is mostly straight, and therefore easier to control.
Watch your opponents. By noticing their eyes and postures, you can predict where they’ll send the ball, start walking over, and be there on time.
Try to get your opponents out of position. When they struggle to get the ball back, they are much more likely to place it right to you, rather than make you run.
Assuming your health practitioners agree, work on regaining your knee flexibility. Eat well, avoid risky moves, such as lifting furniture, and play pickleball moderately, not all day long, until you recover. Focus on exercises designed to help your knees. Wear knee braces if appropriate for your condition.
Know that it is possible to have a gread deal of fun, even if you can’t be super-competitive. Enjoy playing with lesser players. Maybe even look into the joys of coaching, rather than so much competitive play.