Two charged after police officer assaulted

Two men have been charged after a police constable was knocked unconscious in an attack in Sydney's inner west.

The female officer fell to the ground, hit her head and was knocked unconscious during an altercation with a 38-year-old man, police say.

A bystander helped the woman until paramedics arrived and she was taken to Royal Prince Alfred Hospital where she remains in a stable condition.

Additional police attended the scene and arrested the 38-year-old man, while a second man, 47, was also arrested after allegedly taking police items including keys and a search glove.

Both men were taken to Newtown police station and charged.