Do you know the device name of your root partition? If so, just use it as the target of fsck, e.g:
If not, it's probably easier to boot your installation image and fsck the all hard drive partitions from there until you find the root partition that needs fixing.
Code:
fsck /dev/sda1
fsck /dev/sda2
fsck /dev/sda3
...
As long as partitions aren't mounted, an unnecessary fsck won't do them any harm at all.
An initramfs btw is just a little temporary root filesystem in ram with basic software that the kernel mounts and then uses to find and load the drivers for the real root partition on the hard drive.