The punch-up happened outside the Brave Old Oak in Watling Street between 11.30pm on Saturday, October 19 and 1am on Sunday, October 20.
But detectives today circulated a new appeal for witnesses to the incident.
A Northamptonshire Police spokesman said: "A woman was outside the pub talking to a group of people when she was approached by another woman.
"After a few minutes, a man who was with the second woman shouted at the victim and attempted to hit her. two men stepped in to protect her which sparked a mass brawl.
"Anyone with information or who may have seen this incident can call us on 101 quoting reference number 20000021711."