What has the physio said about the pain?
You're very soon after major invasive surgery where bone has been cut, drilled etc (cutting through the periosteum on the outside of the bone is super painful)
If you've got a lot of swelling which is likely, the pain might be partly due to the swelling shifting due to gravity and blood draining down the leg as well as from the surgical trauma to the bones and structures in the knee
Try and ice before you get up so pain is reduced, see if that helps
Before you travel to your appointment, load up on pain meds, lie on the back seat of the car with your leg elevated on pillows with calf and ankle well supported. Does the hospital not have an elevator which seems astonishing? Contact them in advance and ask for someone to meet you with a wheelchair
Good luck, you need to think about recovery from such major surgery in terms of weeks if not months and not days and it won't be linear either, you'll have ups and downs along the journey. It's a marathon not a sprint
