Getting up after a fall

Our user asked: "Hi, I have an elderly parent with both knees replaced who has fallen and cant get up off the floor by themselves. I have printed up a step by step of how to get up after a fall for them to practice. However, when they tell someone to roll over on all fours (hands and knees). My mom and dad both complained that it hurt too much to be on their knees in order to stand up. Whats another technique to have them stand up where it doesn't hurt their knees? Is it ok to go on the hands and knees when they have a total knee replacement (4 year old knees or older)? http://www.learnnottofall.com/content/what-if-i-fall/learn-to-get-up.jsp"