Intraoperative navigation of patient-specific instrumentation does not predict final implant position

The purpose of this study was to determine if intraoperative navigation predicted final implant position of total knee arthroplasties (TKAs) performed with patient-specific instrumentation (PSI). We retrospectively reviewed 60 TKAs performed with PSI and imageless navigation. These values were compared to postoperative coronal alignment based on long-leg radiographs, as well as rotation and tibial slope based on CT scans. The intraoperative coronal position of the tibia as measured by the intraoperative navigation indicated a significantly higher deviation from the neutral mechanical axis than the actual final position (P= 0.03). Similarly, tibial slope and femoral component rotation measured by intraoperative navigation significantly deviated from the final slope and femoral component rotation (P < 0.0001). In conclusion, intraoperative navigation of PSI position showed a significantly high deviation from the true final implant position. Level of Evidence: Level III, therapeutic. See Instructions to Authors for a complete description of levels of evidence.