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

UNLABELLED: 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.