Surveying tibial trials for knee arthroplasty

A tibial trial system comprising:

• a base component having an upper surface and a lower surface;
• an articulating component having a superior surface and an inferior surface;
• a rotary joint extending from the upper surface of the base;
• at least one rotation sensor positioned on the upper surface, said rotary joint engaged with the inferior surface of said articulating component so that said articulating component can rotate relative to the base component;
• and
• an aperture on at least one of said superior surface or a front face of said articulating component and a corresponding groove on said base component, said groove having a semi-circular or circular design to correspond with a rotation of said aperture as said articulating component rotates relative to said base component.

A tibial trial system comprising:

• a base component having an upper surface and a lower surface;
• an articulating component having a superior surface and an inferior surface;
• a rotary joint extending from the upper surface of the base;
• at least one rotation sensor positioned on the upper surface, said rotary joint engaged with the inferior surface of said articulating component so that said articulating component can rotate relative to the base component;
• and
• a rotary joint that allows for incremental changes in the amount of tibial posterior slope between said base component and said articulating component.

A method of using a tibial trial system comprising a base component having an upper surface and a lower surface;

• an articulating component having a superior surface and an inferior surface;
• a rotary joint extending from the upper surface of the base;
• and at least one rotation sensor positioned on the upper surface, said rotary joint engaged with the inferior surface of said articulating component so that said articulating component can rotate relative to the base component, said method comprising:
• using a set of position marks generated by a computer assisted device to determine a placement position for said tibial trial system in a patient's knee joint;
• inserting said tibial trial system in the determined placement position;
• registering a rotational position of said articulating component to said base component;
• articulating the knee joint through flexion-extension, where said articulating component rotates with a femoral component and a series of measurements are made by the computer assisted device, where the computer assisted device records and determines an optimum internal-external rotation relative to said base component;
• and
• removing said tibial trial component to allow the computer assisted device to mill a keel hole or mark a position for the keel hole for a final tibial component placement in the determined optimum internal-external orientation.