Dislocated kneecap

This morning I was able to sleep in.  I stayed up waiting for Robert to get home from his swim meet last night, so he got up this morning to get Catherine to the bus for her meet, and for Robert to get off to his Navy event.  I hadn't slept well all week, so I really allowed myself to sleep.  By the time I got up, Robert had already returned from his Navy commitment.  He was in our living room as I was walking out of our bedroom hall, and as I saw him beginning to sit down on the couch, I heard a "pop".  Robert instantly grabbed his leg, and then said, "My knee is gone".  Sure enough, even through denim jeans, I could tell his knee cap had moved.  I yelled for Andrew, and by this point Robert was in tears.  He has a really high pain tolerance, so I knew he was in a lot of pain.  I also knew that he was thinking this could hurt his Navy career and was scared.  Robert couldn't walk and Andrew wanted to call an ambulance.  I didn't think that was necessary, but we did need help.  Andrew first called our doctor, who of course was not in on a Saturday morning.  He then called our school's athletic trainer.  Greg was wonderfully helpful.  Not only was he able to talk Andrew through relocating it, he spoke to Robert and told him that he needed to trust his dad and try to relax.  Fortunately, the pain and swelling have been minimal.  He had no where he needed to be today so he has been able to stay off of it for the most part.  It was so odd...all he did was try to sit down on the couch (although he did kind of plop onto our nice piece of furniture...maybe it was karma?) and the knee went out.  Certainly an interesting beginning to our day!