Dx psoriatic arthritis (knee) but now have constantly sore feet and big toe joint? same condition? or just consequence of limping?

See your doctor: Psoriatic arthritis can affect the small joints of the hands and feet so you will probably need an xray to take a closer looks at the joints.

Might be: It's a stretch to say a big toe joint is painful because you're walking funny. Given your history of psoriatic arthritis, i would rule that out before anything else.

Both possible: See podiatrist for evaluation, x-rays and diagnosis. Then proper treatment can be initiated.