The 38-year-old revealed he has one leg shorter than the other.
Osman said, "At the time I felt like I was the only person in the world this had happened to, that I couldn't tell anybody because Everton wouldn't want to sign a player with one leg longer than the other!
“Further down the line though I found out it's not necessarily commonplace, but quite a number of people had it.
“But that was a mistake by me. Maybe if I'd told the club initially when I signed, we may have been able to give me something to adapt my body. All of my injuries came because I played my whole first season with that not being remedied."