Abstract: A surgical cement cartridge, for loading with surgical cement and for ejecting surgical cement at a surgical site, comprises a substantially tubular casing comprising a peripheral wall surrounding a longitudinal passage, the passage having an open front end and a remote rear end. A first piston unit is located in the passage for free sliding movement from the front end towards the rear end in response to input of surgical cement into the front end of the casing. A second piston unit is located in the passage adjacent the rear end for forcible driving forward along the passage to cause the first piston unit to eject cement from the first casing end toward a surgical site, the second piston unit having seal mechanism for positively blocking flow of surgical cement axially therepast.