And the 68-year-old action man joked that the severity of the injuries was related to the quality of his films. Stallone sustained a back injury - one of a number of mishaps for the stars of the new movie.
He said: "I grade the quality of a film by the intensity of the injuries. When I shot 'Stop! Or My Mom Will Shoot', I never got hurt. Through 'Rambo' and 'The Expendables', I break my neck and my spine and I dislocate both shoulders.
"In this one here, I end up really taking a fall on my back and had some metal put in there, so if you hear any squeaking, it's not my shoes but my back. But I'm getting better."
Stallone was joined by co-stars including Jason Statham, Wesley Snipes, Antonio Banderas and Kellan Lutz ahead of the film's world premiere in London last night.