A man suffered a dislocated kneecap when he was attacked from behind in Aylesbury early on Saturday morning.
The 43-year-old victim was walking home along Buckingham Street, heading towards Sainsbury’s, when someone ran up behind him and pushed over.
His attacker ran off in the direction of Market Square but the victim did not see who it was.
The victim was taken to Stoke Mandeville Hospital for treatment.
The incident happened at about 2.30am.
Call police on 101 or Crimestoppers anonymously on 0800 555 111 with information.