When I couldn’t sleep I would often get up in the middle of the night and go on my stationary exercise bike for 5 mins (no tension). This would help with circulation and make the knee less agitated
I think the lack of movement when we are in bed causes a lot of problems.
You might also try taking a magnesium supplement during the day and at bed time. Melatonin helps too
Also, Lyrica (prescription) was a game changer for helping me with restless legs and the nerve pain I was having which in turn really helped with sleeping.