I am lucky enough not to need this type of surgery, but my wife has had both a total hip replacement ,and a total Knee replacement ,and she says the hip is a walk in the park compared to the knee. You must start moving the knee as soon as possible after surgery,and you may need to put the leg in a machine that moves the leg for you at the start. This machine can be adjusted from slight movement to extreme ,as one gets better. The machine can be rented ,or in her case was prescribed by the surgeon. In any case its a tough road and only you will know when your ready to drive again!. My wife was 70 at the time of her knee replacement. It was a must and after all the pain ,she says it was well worth it, although in your case your having both done at the same time, that will be tough!!!! Good luck to you ,and don't try and rush the healing to much!!! Stu.