Sylvester Stallone says he 'never fully recovered' from the injuries he sustained on the set of the first 'Expendables' movie: 'It did such a number on my body'

Stallone broke his neck while shooting a fight scene with "Stone Cold" Steve Austin in "The Expendables." It left him requiring an operation and a permanent metal plate.

• Sylvester Stallone said he is still affected by injuries he sustained on "The Expendables."
• He broke his neck on the set of the 2010 film, and needed a metal plate inserted.
• "Truthfully, I never fully recovered," Stallone said in the Netflix documentary "Sly."

In the new Netflix documentary, "Sly," Sylvester Stallone reflects on his over 50-year Hollywood career.

Though the actor is perhaps best known for his roles in the "Rocky" and "Rambo" films, in 2010, he launched yet another action franchise: "The Expendables," which he directed and co-wrote.

Stallone has said that it was on the set of that movie — which has since spawned three sequels — that he sustained his most serious and long-term injuries, which still affect him to this day.

Stallone, who is known for performing his own stunts, was 62 in 2009 when he broke his neck shooting a fight scene with the wrestling star "Stone Cold" Steve Austin. It left Stallone requiring an operation for a hairline fracture and a permanent metal plate inserted in his neck.

"Truthfully, I never fully recovered," the now 77-year-old Stallone said, reflecting on the injury in an interview for "Sly."

"It did such a number on my body, I've never been the same. Never."

With the distance of nearly 14 years, he said he's asked himself, "Was it really worth it?"

He mused: "Are you doing this for people's approval? Really, that's almost like a child needing a pat on their head by their father. That's constant encouragement. But it's true."

Stallone's rival-turned-friend and "Expendables" costar Arnold Schwarzenegger also weighed in on the accident.

"It's not uncommon for an action hero to get injured on set, but I think it is clear that Sly drove it to the extreme," Schwarzenegger said. "I thought it was too much."

The news of Stallone's injury was not made public until after filming had concluded and the actor began promoting the movie in 2010.

He told FHM magazine (via The Guardian): "Man, it was seven guys, kicking each other's ass, one guy tougher than the next. No joke, our stunt guys were begging for mercy."

"Actually, my fight with Stone Cold Steve Austin was so vicious that I ended up getting a hairline fracture in my neck. I'm not joking,' he continued.

"I haven't told anyone this, but I had to have a very serious operation afterwards. I now have a metal plate in my neck."

Stallone's Barney Ross was billed as the main character in the first three "Expendables" films, but had significantly less screentime in "Expend4bles," which was released this summer, owing to the fact that the actor officially walked away from the franchise with a $20 million payday in March 2017.