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What is An 18-yr-old boy was playing football when he suddenly twisted his knee on the ankle and he fell down. He got up after 10 minutes and again started playing, but the next day his knee was swollen and he could not move it. The most probable cause is - and explain in detail?
This boy has : -


History of twisting injury to the knee
Swelling appearing next day.


This is classical to the medial meniscal injury.
In ACL injury swelling appears immediately due to hemarthrosis.