My first knee seemed to suffer from this stiffness more than my second. Anytime I sat at the desk in our den even if I propped it up on a footstool. Sitting in the car for anything longer than 10 min also. I remember with that first knee that it took 5-6 months for that stiffness to ease. Hopefully yours won't last as long but just know that it's totally normal.
United States
