Can you do cardio or any lower body moves without pain? SOunds like you should stay away from lower moves and make fixing the knee a priority.
Loads of tips in these, hopefully some will help
For training to lose fat the fastest pick one compound movement and do heavy like 5x5 60-90 secs rest then everything else supersetted or giant sets for high reps which will create a big metabolic effect as well as add a bit of muscle. Rotate through rep schemes each workout .
Eg bench 5x5
Machine row x15
hammer curl x15
dumbell shoulder press x15
x5 sets, each excercise back to back/no rest then 30 secs rest between giants sets
Alternate between 12, 15 and 20-25reps
As said above keep your calories up just from very clean food sources, like make 90% of your diet from these foods...