Child & knee pain? Not broken!

[MsJemimaPuddleDuck]

My 9 year old woke up on Saturday with pain behind his knee, he was alright just hobbled about.
There is no redness, no heat coming off the knee and no swelling. Its not broken either. He was absolutely fine on Friday and went swimming etc.

It’s now Monday, i gave him today off school as it was sports day which obviously would of been pointless with a bad knee.
hes still not baring full weight on his leg, and keeps complaining.

He is a type one diabetic but his blood sugars are in range & no ketones if that makes a difference.
The only thing I can think of is that its been hot and hes dehydrated, hes been very awkward and refusing to drink anything other than milk. 🙄

Any ideas what it could be? I did wonder if its growing pains as hes going through a growth spurt but usually it lasts a few hours-day and its gone not 3 days! Hes rested it all day as well.

Does the pain increase if he tries to bend his ankle upwards? If so it could be a tight calf muscle.

Sometimes but then othertimes no! Hes got a GP appointment this afternoon to get him checked out but its driving me mad. He complained he was tired again this morning and gone back to sleep which isnt like him & still cant walk.

Could be so many things I had osgood schlatters growing up. Is he hitting a growth spurt?

yes, we had him measured last week and hes shot up 4 inches in 3 months. I was thinking it could just be pain from a rapid growth spurt but it would
of been both legs i thought.
i dont think its osgood schlatter as no inflammation. We have hypermobility EDS in the family me and his older brother have it but when they tested my son (just did his arms 🙄) they said no hypermobility.

Took him to be seen GP wasnt sure but said shed ring the fracture clinic incase they want to see him but said no obvious signs of a fracture? So not very helpful!
Hes done some walking today which has eased up his leg pain so maybe just a case of stiffness & dehydration. 🤦🏻‍♀️