Harrodsburg Police said a World War II veteran, thought to be suffering from a war flashback, held a nursing assistant at knife point at James B. Haggin Memorial Hospital in Harrodsburg.
The incident Thursday morning led to a brief standoff and lock down at the hospital.
Investigators said Dewitt Sims, 92, of Harrodsburg, was a patient at the hospital.
Police said apparently Sims thought he was being threatened by the enemy.
Investigators said when they arrived, Sims was holding a pocketknife to a nursing assistant's throat.
Investigators said Harrodsburg Police Chief Billy Whitenack began talking to Sims, slowly approached him and managed to get the knife away from him.
Police said the nursing assistant, whose name was not released, suffered minor injuries to her elbow.
Police arrested Sims and charged him with two counts of 1st Degree Wanton Endangerment.
Sims was held in the Boyle County Detention Center.