I take a lot of weight through one arm when going down the stairs (usually my right as my right knee's worse than my left). The sequence is bend a bit -> reach forward -> grab handrail -> grip it and lock elbow -> swing left leg -> step with right leg: it means you're not taking all your weight through that knee and hip. Maybe something to try? (gently!) You can always alternate if both legs are bad...
I've given up on the stairs at work, the main stairwell is quite a tight spiral up the centre of the atrium - looks pretty but you can see the ground through the steps/handrail and it makes my balance go funny
Worst is when you meet people coming the other way - it's only wide enough for two people but the awkward shuffling as you both decide which side to take gets me in a flap!