Arthritic knee with shooting pain only at night

There is a proven link between knee pain and muscle deterioration and exercise should help. When I injured my knee a few years ago I read a book called "Treat your own knees" It gives details of exercises that can help. The simplest one that can be done even when you have weight bearing problems is simply putting a cushion behind your leg as you stretch it out in front of you on a bed or couch and contracting the muscle to push down into the cushion, holding it there, then relaxing, and repeating, building up the repetitions. It's one you can do watching TV or reading or even typing on GN!!!

Is that using your thigh muscle, calf muscle, or both, Glorianny?

Think it is both MaizieD but the important one is the thigh muscle which helps stabilise the knee. According to the book people with good muscle development report less pain although sometimes their joint deterioration is the same or even worse.
It's basically just pushing down into the cushion holding then releasing. It helped me when I had a knee injury.

It is one of the exercises I have been advised to do for my arthritic knees.