Experience using the latest OrthoPilot TKA software: a comparative study.

The OrthoPilot (Aesculap, Tuttlingen, Germany) Knee Navigation System represents a computed tomography (CT)-free system. In older software versions, a rigid-body at the iliac crest was necessary to calculate the centre of the hip. The latest software versions, 3.0 and 4.0, use a new mathematical algorithm to reconstruct the mechanical axis. Using the OrthoPilot system, an intraoperative cinematic study can be done that results in calculation of the mechanical axis and navigation of resection cuts. According to flexion- and extension-gap balancing, the anterior/posterior (a.p.) position and rotation of the femoral component also are navigated. Thirty navigated SEARCH (Aesculap, Tuttlingen, Germany) total knee arthroplasties (TKA) using the software version 3.0 of an uninterrupted series were evaluated, versus 30 navigated knees using older software and a manual group. Results concerning alignment were determined to be superior to the older navigation and manual groups. The number of cases with a good mechanical axis, 0; low; or 2 of deviation from optimum, was reached in 17 of the manual, 19 of the older-version, and 27 of the newer-version navigation cases. More features were solved in a convincing manner. The numbers of ouliers were diminished. Navigation in TKA using the OrthoPilot has become more safe and effective.