Nothing major. Just arthroscopic surgery to remove his ankle screws. He will be out for 4-6 weeks missing his country's World Cup fixture against Ukraine.
Eduardo has had a number of niggling injuries that have hampered his complete rehabilitation since his return.
It is tough to say this but I doubt he will ever be fully match fit. An ankle surgery of that magnitude works well when your occupation is sedentary or fairly sedentary. But when it comes to football with its shearing torques and loading of the ankle, a small compromise in the structural integrity of the bones and/or the supporting fascia, including muscles and ligaments can prove detrimental in the long term.