Can Knee Be Moved Freely While On Knee Brace For Tibial Fracture?

I have a hairline fracture of the tibial plateau. Fell a week ago. I OS said no surgery, put me in a bending knee brace and said crutches and no weight bearing for 6 weeks. My leg feels great and most swelling has gone down, My question is: can I move knee in any way that feels comfortable as long as I put no weight on it and can I do some simple leg excercises like leg lifts just to keep it moving? Or what other excercises can I do on that leg that would help?