An orthopaedic surgical instrument includes a polymeric femoral trial component (14) for coupling to a surgically-prepared distal end of a patient's femur. The femoral trial component includes an articular side (62) having a posterior femoral condyle surface and a fixation side (64) that is opposite the articular side. The fixation side has a plurality of ribs (66) that extend in a direction away from the articular side so as to define a plurality of pockets (108) between them. Each rib has an outer surface (68), and the outer surfaces of the ribs define a posterior fixation surface (82) that extends generally in the superior/inferior direction and is configured to match the surgically-prepared distal end of the patient's femur. The femoral trial component also includes a plurality of teeth (110) extending from the posterior fixation surface in a direction away from the articular side. Each tooth of the plurality of teeth has a pointed tip (116) that defines a longitudinal axis (122) of the tooth extending in the medial/lateral direction.