Method of surgically preparing a patient's tibia

A method of surgically preparing a patient's tibia, the method comprising:

• positioning a guide tower on a surgically-prepared proximal surface above an opening of a medullary canal of the patient's tibia, the guide tower defining a first axis,
• attaching a stem trial to a lower end of an offset tool that is sized to be received in the guide tower,
• advancing the stem trial through the guide tower and the surgically-prepared proximal surface into the medullary canal, the stem trial defining a second axis parallel to the first axis,
• rotating the offset tool in the guide tower to move the guide tower on the surgically-prepared proximal surface such that the first axis is moved in a circular path about the second axis,
• identifying a desired offset orientation of the guide tower,
• adjusting a stem adaptor based on the desired offset orientation,
• securing the stem trial to the stem adaptor,
• inserting the stem adaptor and the stem trial into the medullary canal, and
• engaging the surgically-prepared proximal surface with a tibial base trial secured to the stem adaptor.

A method of performing an orthopaedic surgical procedure on a patient's tibia, the method comprising:

• securing a stem trial to a stem adaptor,
• advancing a fastener secured to a tibial base trial into a threaded aperture of the stem adaptor such that the stem adaptor is secured to the tibial base trial,
• rotating a first adaptor body of the stem adaptor relative to a second adaptor body of the stem adaptor to position the stem adaptor in a desired offset orientation,
• advancing the fastener deeper into the threaded aperture to lock the first adaptor body and the second adaptor body in the desired offset orientation,
• inserting the stem adaptor and the stem trial through a surgically-prepared proximal surface of the patient's tibia into a medullary canal of the patient's tibia, and
• engaging the tibial base trial with the surgically-prepared proximal surface.