What are the best therapies for a knee click when walking up stairs?

Find the cause 1st. A clicking sensation in the joint is due to something getting caught between the joint surfaces. The stair climbing puts extra pressure on the joint and exacerbates the clicking. It's usually due to a loose body of calcium like a bone spur from arthritis broken off in the joint or a torn piece of cartiladge like a torn meniscus getting caught in there. Start with an x-ray, then maybe an mri.