WARSAW, Poland — The head of a Warsaw hospital said Friday that the leader of Poland's ruling party, Jaroslaw Kaczynski, has been discharged following treatment that has "stabilized his health condition."

The 68-year-old Kaczynski suffers from a knee problem and was seen limping and using crutches before he was admitted to the military hospital in Warsaw in early May.

His long hospitalization had raised questions about his health and control over Polish politics. His conservative Law and Justice party has a majority in parliament and single-handedly runs the government. Although he is only a lawmaker and keeps a low profile, Kaczynski is considered to be Poland's most powerful politician and the architect of its politics.

The head of the hospital, Grzegorz Gielerak, said in a statement that Kaczynski will continue his treatment as an outpatient.

The team that treated Kaczynski concluded that the hospitalization served to establish a diagnosis and for "conservative medical procedures that have brought an improvement and have stabilized his health condition," the statement said.

TV footage showed Kaczynski, with a brace on his right knee and with crutches, carefully getting into a limousine at the hospital door, and then getting out at the gate of his house.

"Thank you for your interest," he told waiting reporters, and walked toward the house.