Swollen knee in child

[Doors247]

I know I should post in childs health but I don't seem to get any replies.

A couple of months ago my 8 year old dd started complaining of a bad leg.
I had a look and one of her knees was a lot more swollen then the other.
No trauma or no injuries just out of the blue.
We were advised by 111 to take her to the walk in which while there they did a xray and checked it ou, they wasn't sure what was wrong but to keep an eye etc.
Then knee went down after a week until now.

Out of the blue the same exact same thing has happened.
Lots of pain and very swollen knee, I will get a GP appointment now but while I'm waiting I just thought I'd ask if anyone had any ideas of what could be causing it?

Looks like my youngests did when she had septic arthritis. Has your DD had a temperature at all?

Mine ended up having it drained under a general and then an inpatient stay for 5 days of IV antibiotics. This was at the height of covid too.

No lasting effects other than a less than 1cm surgical scar on her knee.

osgood schlatter? She's about the right age.

JIA? (Juvenile idiopathic arthritis)

I did look at that, her pain is more in her upper leg and not so much in her knee.
She doesn’t do any sport or anything like that either.
But hopefully (compared to a lot of other things it could be) it is this.

No temp and she didn't have a temp last time.