Ideas for leg extension training at home?

[FreeLitres]

I am just recovering from a leg operation and my physio said I will soon need access to a gym to use a leg extension machine for my quads.

Getting to a gym will be difficult as I can't drive yet.

Without investing in a full on multigym, does anyone have any ideas for doing this kind of excercise motion at home? He said squats are not a good idea as I need to really isolate the quads. I'm ideally looking for something that doesnt take much room, would ideally be folded/dismantled out of the way when not in use. The weights will have to start very light at first but it would be handy to increase the resistance as I get stronger.

Any ideas?

[Fas1975]

Fitness bands. You can get them in varying resistance settings. Sit down, wrap the bands around both ankles or at least to something static, whilst one foot on the floor, extend other leg, swap as needed.

Something like this motion