It’s called a CPM (continuous passive motion) machine. It’s pretty standard at the hospital I work
If you’ve got options on where you have the procedure done I’d advise checking out facilities as much as mds. A hospital or branch of a hospital that is dedicated to orthopedic surgeries can often provide more consistent care than somewhere where you’ll be placed with more varied surgeries. Also, they often have lower incidences of infection which is a big deal if it occurs in a joint or bone postoperatively. The other posters are right on with the physical therapy. It should not be excruciating but will require some self will to participate fully (plus narcotics for most people).
You should get organized & comprehensive preoperative teaching, either from the hospital or MD. We’ve got an actual class that patients are expected to go to previous to surgery. How to prepare, what to expect before & after surgery & when you go home.