A spiked head assembly for a tibial jig for use during an orthopaedic surgical procedure, includes a body and a mount for mounting the spiked head assembly on the tibial jig. The spiked head assembly comprises an elongate member having a central longitudinal axis, a first end and a second end and superior and inferior surfaces. The elongate member also has least one securing spike provided on the inferior surface towards the second end of the elongate member and configured to engage with a bone mass and arms extending from the elongate member in a direction perpendicular to the inferior surface. The arms are spaced apart from a plane that includes the central longitudinal axis and extends substantially perpendicularly to the inferior surface, so that the arms and the inferior surface define an access space for the surgical procedure.