The first focus of rehab is preventing stiffness

The end result of failed rehabilitation is knee stiffness - either a limitation of flexion (bending) or a limitation of extension (straightening) or both. This is what good rehabilitation tries to avoid and why so much of the focus is on range of motion (ROM).

A Primer is an ABC

ABC icon with book

Rehabilitation is a process

If you can understand what the process is all about, then you are halfway there.