It's not normal for an 8 year old to havebadly cracking knees which ar epainful is it?

[saltire]

I wonder if it's a leftover from the Slapped cheek, Ds2's knees crack very loudly and he creis as he says it's sore. he and I ahd slapped cheek really badly away back in February, swollen joints, painful joints and a red rash was the symptoms we both had