CARDIFF have lodged an official complaint with the United Rugby Championship after an incident that has left Dragons scrum-half Gonzalo Bertranou needing surgery.

The Argentina international is spending the rest of the season on loan at the Arms Park before leaving the Rodney Parade club this summer.

Bertranou started for the Blue and Blacks in last week’s game against the Lions but came off in the 19th minute of the 34-13 defeat in Johannesburg.

Cardiff confirmed that the Pumas international suffered a concussion and a fractured cheekbone, leading to an early flight home for an operation.

"I don't usually say this but I wasn't very happy with the action that led to the injury," said head coach Matt Sherratt.

"It looked like a swinging arm [and] we've gone through the right channels with it.”

The incident, which involved Lions lock Willem Alberts, has left Cardiff down to Ellis Bevan as their only specialist scrum-half for Saturday’s game with the Sharks.

Fly-half Tinus De Beer will cover but he is the only specialist 10, with centre Ben Thomas ready to pull the strings if needed.

Bertranou has made three appearances for Cardiff and hasn’t been ruled out of the Judgement Day clash with the Ospreys on Saturday, June 1 yet.

The 30-year-old is leaving the Dragons but is yet to sign an extended contract with the Blue and Blacks despite catching the eye.

"He's made a great impression at Cardiff and is one of the top professionals I have worked with, he maximises every ounce of talent" said Sherratt.

"We still haven't got absolute clarity on our budget, so we are holding off.”

The Dragons will go into next season with Rhodri Williams and Dane Blacker as their senior 9s, pushed by the promising pair of Che Hope and Morgan Lloyd after impressive campaigns with Newport and Pontypool.