World Rugby has intervened in the latest concussion case involving George North, questioning why established protocols weren't followed and the reasons behind a review panel's decision not to sanction his English club Northampton.
North was allowed to return to the field of play by Northampton's medical staff, despite appearing to lose consciousness after he landed on his head following a tackle in the air during a match against Leicester on December 3.
Northampton said its doctors did not have access to full television footage that suggested North had been knocked out, and were happy for him to continue playing.
The Concussion Management Review Group, set up by England's Rugby Football Union, assessed the case and said on Wednesday that Northampton would not be punished, despite saying North should not have returned to the field.
After looking at the case, World Rugby said on Friday it was "disappointing that apparent non-compliance with the sport's elite head-injury protocols led to George remaining on the field of play when he should have been immediately and permanently removed".
The governing body raised concerns that there was a "failure in the identification and management of the injury," especially considering North's history of concussions.
The winger suffered three concussions on club and international duty between November 2014 and March 2015, forcing him to spend time away from the game on two separate occasions.group.
North hasn't played again since the match.
World Rugby has made the handling of concussions a priority in recent years.