Christoph Kramer continued playing despite head injury
German midfielder took shoulder to head in World Cup final
Germany midfielder Christoph Kramer's head injury in the World Cup final has revived concern about the way football deals with concussion.
Kramer continued playing for 14 minutes Sunday after taking a heavy blow to the face in a collision with Argentina defender Ezequiel Garay.
The 23-year-old Kramer was replaced in the 31st minute after slumping to the ground.
He appeared to be disorientated when helped off the field by medical staff.
Argentina players Javier Mascherano and Pablo Zabaleta played on in the semifinal against the Netherlands after sustaining head injuries. Both players started in the final.
Questions about FIFA's concussion protocol were first raised in the group stage when Uruguay defender Alvaro Pereira refused to leave the field after being struck in the head by an England opponent's knee.