Zac Efron wrecked his left knee while snowboarding.
He tweeted from the hospital , (quote) “I tore my ACL shredding the gnar -- but all is good. I opted for surgery so I can come back stronger than ever.”
“Shredding the gnar” is slang for epic and gnarly conditions. Snowboarding in deep powder at high speeds and extreme downhill inclines.
ACL is a medical abbreviation for a vital ligament that stabilizes the knee. Most pro athletes are out of the game for an entire year after tearing an ACL. ( Entertainment Tonight )