It was the hit felt by Houston Texans fans everywhere. Star linebacker Brian Cushing taken down by what some are calling a dirty hit by New York Jets guard Matt Slauson.
A day later, the worst fear confirmed: A torn left anterior cruciate ligament (ACL).
Orthopedic surgeon Dr. Alfred Mansour with the Memorial Hermann Ironman Sports medicine Institute told Local 2, "If you do sports, if you do anything that involves cutting and pivoting, then you're putting yourself at risk for getting an ACL tear."
Mansour added that ACL repairs are the second most common procedures done by orthopedic specialists. A foot plant with a sudden knee twist can cause the ligament to hyper-extend and "snap."
He explained, "(With) a normal knee ... when you pull forward, (the ACL) gets tight. Whenever this ligament is ruptured and you pull forward, there's no stop."
Mansour said more than 90 percent of the time arthroscopic surgery is the best option, no sooner than 10 days or even three weeks after the injury to allow the swelling to go down.
It's a season-ender for Cushing, but not necessarily a career-ender.
Mansour explained, "I've seen several players that are back and have had phenomenal careers post ACL (repair) and some guys just can't get over the hump of that exposure. They see a blocker coming at them and it's just a millisecond hesitation before they change direction or it just doesn't feel quite normal, so it's hard to predict."
For most people, it's about six months after ACL surgery before you can return to normal activity, but Mansour said for high level athletes, it's more like nine months.