If you cannot bend your knee after a fracture, you must get regular treatment for the fracture and make sure there is bone scab growth before you can do functional exercises for bending your knee. If you have the conditions, you can also go to the rehabilitation medicine department of the hospital, after giving physical therapy, the rehabilitation therapist will give joint loosening to help it recover faster. If the knee joint is not fully 90 degrees, you can use the healthy foot to sit on a stool or sit on a higher bed to give passive bending, and if the bending is more than 90 degrees, you can use squatting to bend the knee joint.