Building it up!

Hello I am wondering if any of you with knee OA have been able to build up to 15k steps a day without flaring? The first time I had a flare I recovered so well that I could do 6 miles hikes with zero pain. The most recent flare has been more troublesome and I seem to be stuck at about 5 - 6k steps a day and two swims per day for almost 3 months now. My ortho says I likely did not make it worse as there was no palpable swelling. Every time I bump things up or try something new my knees get hot and stiff. No pain beyond minor soreness and at time non palpable swelling. Recently I have been able to handle hills well at the last! Thanks for listening!