Sydney man falls off roof, impales knee

A man has fallen from a roof and impaled his knee on a fence in inner Sydney.

Paramedics rushed to Alexandria at 9am Thursday to find the 68-year-old with injuries to his right knee, NSW Ambulance said.

He's been taken to Royal Prince Alfred Hospital in a stable condition, police say.

Unconfirmed reports say the man was on a worksite when he slipped and fell.