CW-XMen's Stabilyx Joint Support 3/4 Compression Tight, Capri Pants for Running and Recovery

If I have knee pain, will these tights be enough to recover\prevent pain or do I also need knee braces?

I'm 5'7" & 250#s. No gut but not your traditional gym bod (26in thighs, 40in waist, 30in inseam, stocky endomorph). What size would be best?

Is there a Sizing chart ?

I have lymphodema. my pt has recommended tights with 20-30 mm hg compression. what is the compression on your tights?