Hi Josephine,
Be patient. I'm quite sure your knee pain will resolve over time. I had knee pain prior to surgery and I was very disappointed to find that it returned after surgery. I also had some inward rotation of my leg, particularly my knee, while walking. All of this was caused by some very specific weaknesses that had developed prior to surgery as I had compensated for my painful hip for a long time. Those weaknesses became temporarily more severe after the surgery due to the muscles that were affected by the surgery. I started doing physical therapy at about 10 weeks post-op to help correct the muscle weaknesses. I'm now almost 4 months post-op and my knee pain has been gone for many weeks and my inward rotation has improved greatly, almost to complete resolution. I still have a little bit of inward rotation when walking up a steep hill. My hip feels great and is now stronger that pre-surgery. The only issue that I have is some tightness of the muscles in my groin. These muscles have been tight for many years. So, I probably shouldn't expect them to loosen overnight. But, at this point, I'm pretty confident that they will over time.
Be patient. Give your body time to heal and time to undo all of the habits that develop when we compensate for our pain prior to surgery.