The knee is a hinge joint that will never respond well to rotational forces. Gray Cook's joint-by-joint approach to training states that lack of stability in the knee is usually caused by lack of mobility in the ankle. Michael Boyle's 8 Essential Mobility Drills suggests placing your toe four inches from a wall, keeping your heel on the floor, and rocking your ankle by touching your knee to different places on the wall.
Myself, since it's dancing, I would suspect that you need to be moving your hips as well. Maybe training your hip rotators with clam shells and reverse clam shells. But that might not be how you get a high score.