BRASILIA (Reuters) -Brazilian President Luiz Inacio Lula da Silva was admitted to hospital on Friday to undergo surgery for hip arthrosis caused by wear and tear of the cartilage on the head of the femur that has caused him much pain in recent months.

Lula has said he has been in constant pain for more than a year, though this has not stopped him from traveling to dozens of countries since he took office in January.

The two-hour surgery with general anesthetic is aimed at restoring the function of his right hip by arthroplasty, which involves removing the head of the femur to implant a prosthesis.

While the surgery is not risky, 77-year-old Lula will remain in hospital until Tuesday and then spend three weeks at the presidential residence recovering.

"I have to be a little careful because the operation seems simple, but physiotherapy and dedicated treatment are essential for a recovery," he said on Tuesday in a television interview. "I will take great care of myself. I'm very optimistic."

Lula said he will only be able to resume his presidential trips abroad at the end of November, when he will travel to the United Arab Emirates to attend the COP28 global climate meeting.

"Until then, I will stay here in Brasilia. I won't be able to catch a plane," he told the government TV channel.

Vice President Geraldo Alckmin will take in some of Lula's duties and public appearances, but there are no plans for him to become acting president at any time, government officials said.

Lula said he put off the surgery because he wanted to take office first and lead the country back to normality after political turmoil under his predecessor, and recover Brazil's international standing.

"I wanted to tell the whole world that Brazil is back."

(Reporting by Anthony Boadle; Editing by Steven Grattan and Christina Fincher)