Navigated unicompartmental knee replacement.

Computer-aided systems have been developed recently to improve the precision of implantation of unicompartmental knee replacement (UKR) or total knee replacement. Minimal invasive techniques have been developed to decrease the surgical trauma related to the prosthesis implantation. However, there might be a concern about the potential of minimal invasive techniques for a loss of accuracy. Navigation systems might address this issue. We are currently using routinely a nonimage-based navigation for total knee replacement. We developed a modified system for UKR, suitable for either a conventional or a mini-invasive approach. Navigated implantation of a UKR allowed improving the accuracy of the radiologic implantation. Mini-invasive implantation was effective, but the accuracy may not reach that of the conventional navigated technique and should be still improved. Minimal invasive techniques have to be validated because a loss of accuracy will negatively influence long-term outcomes.