What causes knee problems in adolescents?

Answer 1

A child may have knee pain from hyper-flexive joints (double jointed). The knees don't lock in place and hyper-extend, especially when the childs lays on their back. Putting a pillow under the knees when lieing down may help. And they shouldn't sit with their legs criss crossed.

Answer 2

if your meniscus gets broken or cracked. If your meniscus is too large or too small.