An orthopaedic surgical instrument system for use during a surgical procedure to implant an orthopaedic knee prosthesis, comprising: a tibial base trial component including (i) a superior surface, (ii) an inferior surface positioned opposite the superior surface that is adapted to be positioned on a surgically-prepared proximal end of a patient's tibia, (iii) an opening being defined by an inner wall extending inwardly from the superior surface to a shelf surface positioned between the superior surface and the inferior surface, (iv) a pair of posterior fixation pinholes extending through a posterior section of the shelf surface and the inferior surface of the tibial base trial component, and (v) a pair of anterior fixation pinholes a fixation pin (250, 252, 254) including a head and a shaft extending inferiorly from the head that is sized to be received one of the fixation pinholes of the tibial base trial component, an insert component shaped to be received in the opening defined in the tibial base trial component, and a tibial bearing trial component adapted to be positioned on the insert component, wherein the head of the fixation pin is sized to be at or below the superior surface of the tibial base trial component when the head is engaged with the shelf surface, and optionally the system further comprises a pin extraction tool including a pair of jaws configured to selectively engage the head of the fixation pin, the pair of jaws comprising a first jaw including a semi-circular flange and a second jaw including an arced flange extending less than 180 degrees, characterised in that each anterior fixation pinhole of the pair has a diameter that is greater than each of the posterior fixation pinholes. a tibial base trial component including (i) a superior surface, (ii) an inferior surface positioned opposite the superior surface that is adapted to be positioned on a surgically-prepared proximal end of a patient's tibia, (iii) an opening being defined by an inner wall extending inwardly from the superior surface to a shelf surface positioned between the superior surface and the inferior surface, (iv) a pair of posterior fixation pinholes extending through a posterior section of the shelf surface and the inferior surface of the tibial base trial component, and (v) a pair of anterior fixation pinholes a fixation pin (250, 252, 254) including a head and a shaft extending inferiorly from the head that is sized to be received one of the fixation pinholes of the tibial base trial component, an insert component shaped to be received in the opening defined in the tibial base trial component, and a tibial bearing trial component adapted to be positioned on the insert component, wherein the head of the fixation pin is sized to be at or below the superior surface of the tibial base trial component when the head is engaged with the shelf surface, and optionally the system further comprises a pin extraction tool including a pair of jaws configured to selectively engage the head of the fixation pin, the pair of jaws comprising a first jaw including a semi-circular flange and a second jaw including an arced flange extending less than 180 degrees, characterised in that each anterior fixation pinhole of the pair has a diameter that is greater than each of the posterior fixation pinholes.