El Chapo: Erectile Dysfunction Surgery On the Run

El Chapo came down from the mountains during his time as a fugitive to undergo erectile dysfunction surgery in Tijuana ... according to a Mexican newspaper.

Reforma claims sources close to the investigation told its reporter, Chapo received a testicular implant to improve blood flow ... just a stone's throw from the U.S. border.

The paper claims the surgery required anesthesia and an operating room and involved planting a prosthesis.