I had a lot of hip and back pain walking with a different gait after my first TKR. The hip pain gradually improved as I walked round the street, but because I have scoliosis the backache didn't until the second knee was done and now the hip is playing up again, but I knew it would and it's a different reason, nothing to do with the surgery and altered gait,
I try to do a short walk round the block every day, gradually increasing the distance. I started with 5 minutes and today I did 25 minutes. The new knee was fine, better than the first that can still feel a bit stiff sometimes and the hip kicked in after about 20 minutes. So take it easy if you do go out walking and build up gradually.