Garda Aaron Cawley, now based at Manorhamilton in Leitrim after a transfer from Donegal, said he was off work for nine months after a series of attacks by a man which started in the village of Loughanure and continued at Glenties Garda station.
Garda Cawley said his nightmare started when he was on checkpoint traffic duty in Loughanure village, and 44 year old Philip Moore of Cruckakeehan, Annagry failed a roadside breath-test while driving a camper-van.
He said Moore became extremely aggressive, and there was a struggle which lasted 20 minutes while he tried to restrain and handcuff him.
Moore continued to be aggressive in the patrol car and it took four gardai to place him in a cell at Glenties Garda station.
Moore pleaded guilty to the assault causing harm on Gda Cawley in June 2012.
He was remanded on continuing bail to July 14 for sentence.
Garda Cawley told the court he had surgery to his hip after tearing a muscle in the struggle with Moore and had suffered constant pain for nine or 10 months. He said he suffered nightmares and flashbacks and wouldn't go out in the patrol car on his own.