North Charleston Mayor Keith Summey underwent surgery to repair an existing knee replacement today, his office said.

The procedure went as expected, said spokesman Ryan Johnson. Summey is alert and resting comfortably with his family. He is expected to return to duties at City Hall early next week.

Summey, 64, had double- knee replacement surgery in 2001. The fix was to his left knee.

Summey won a sixth term as mayor last week.