Patent ID: 8361160

Claim:
A method for assessing the positioning of a patella implant for a knee joint of a patient during a navigated knee surgical procedure, the knee joint having a femoral part, a tibial part and a patella, the method comprising: attaching a first component of a trial patella implant to the posterior of the patella, the trial patella implant having a second component that translates relative to the first component in the medial-lateral direction when the first component is attached to the patella, wherein at least one of the first component and the second component comprises a marker; tracking the location of the trial implant patella as the knee joint is articulated while the second component is free to translate relative to the first component by communicating tracking data transmitted by the marker during the articulation of the knee joint to a computer; tracking the location of the trial implant patella as the knee joint is articulated while the second component is fixed in the medial-lateral direction relative to the first component by communicating tracking data transmitted by the marker during the articulation of the knee joint to a computer; and determining (i) a first trajectory of the trial implant patella based on the tracking data communicated to the computer while the second component is free to translate relative to the first component using the computer and (ii) a second trajectory of the trial implant patella based on the tracking data communicated to the computer while the second component is fixed in the medial-lateral direction relative to the first component using the computer; and determining the medial-lateral displacement of the second component relative to the patella over at least a part of the first trajectory or the second trajectory using the computer.