Finland's President Sauli Niinistö will have a hip operation on Wednesday, according to the president's office.
Despite the surgery, Niinistö is expected to be able to perform his duties as usual during his recuperation, according to his office.
However, the president will not be able to travel by air for at least a month.
The president's office announced last May that Niinistö suffers from osteoarthritis, a degenerative condition which - in this case - can wear away cartilage in the hip joint.
According to information from the American Academy of Orthopaedic Surgeons, cartilage affected by osteoarthritis becomes frayed and rough, sometimes causing damaged bones to form bone spurs. The condition - and resulting pain - develops slowly.
Niinistö's office said last spring the president was closely monitoring the progress of his osteoarthritis. However, his medical condition did not prevent him from participating in an informal ice hockey game in Helsinki earlier this month.
Story continues after photo.
Vanhanen out of hospital
Former Prime Minister, and current MP, Matti Vanhanen was sent to a hospital emergency room after feeling dizzy and faint during a campaign event in Espoo on Sunday afternoon.
On Monday it was reported that Vanhanen had left hospital and was planning to take part in parliament's plenary vote this week. However, he remained on sick leave on Tuesday, according to news outlet STT.
Vanhanen attributed his dizzy symptoms to a prolonged bout of the flu, and said he plans to continue campaigning in the city of Hyvinkää on Thursday.