Ryan Crotty in action at Sydney's Olympic Stadium on Saturday. Photo: David Gray/Reuters

SYDNEY – The All Blacks return to New Zealand triumphant after another Rugby Championship demolition of the Wallabies, but with concerns over the long-term health of Ryan Crotty.

The inside centre was knocked out in a clash of heads with new midfield partner Jack Goodhue in the first half of the 38-13 rout at Sydney's Olympic stadium and played no further part in the match.

The 29-year-old has suffered a litany of head knocks over the past two seasons, missing games for the Crusaders in Super Rugby earlier this year, and will be sidelined for Saturday's return match at Eden Park. His sister Shea Crotty, who has played basketball for New Zealand, aired her concerns on social media.

“Know how frustrated he will be but for selfish reasons I want to see my brother grow old and able, not battling the brain forever,” she wrote on Twitter.

All Blacks coach Steve Hansen lamented Crotty's “bad luck” to be hit by friendly fire and said a specialist had already given the midfielder the “all-clear”.
Flank Sam Cane, however, was circumspect about the “fickle” nature of head injuries.

“Everything else has a timeframe but there's just so much unknown with head knocks and it seems like you can be only one away, if it's the wrong one, from it being then end of it,” Cane said yesterday.

With Sonny Bill Williams already ruled out with injury, the All Blacks will have to dig deep into their midfield stocks.

Anton Lienert-Brown, who replaced Crotty on Saturday, or Ngani Laumape are likely to start at inside centre, with the uncapped Vince Aso a chance to be called up as injury cover.

The All Blacks will also be without wing Rieko Ioane, who suffered a hamstring strain, which opens the door for a recall to Nehe Milner-Skudder.

Injuries aside, Hansen would have been immensely pleased with the performance of the champions, who notched their 13th successive win in the tournament after going undefeated in the last two campaigns.

Captain Kieran Read made a solid return to the side after a long lay-off from back surgery while lock Brodie Retallick was brilliant in his first Test for nearly a year, scoring a second-half try and adding huge drive to the All Blacks' scrum.