gms | German Medical Science

54. Jahrestagung der Norddeutschen Orthopädenvereinigung e. V.

Norddeutsche Orthopädenvereinigung

16.06. bis 18.06.2005, Hamburg

CT-free Computer-assisted navigation in the implantation of total knee endoprostheses: Advantages, disadvantages, practicability?

Meeting Abstract

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  • corresponding author H. Schablowski - St. Anna-Hospital, Universität Witten-Herdecke, Klinik für Orthopädie, Herne
  • O. Meyer - Herne
  • G. Godolias - Herne

Norddeutsche Orthopädenvereinigung. 54. Jahrestagung der Norddeutschen Orthopädenvereinigung e.V.. Hamburg, 16.-18.06.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05novK4.05

The electronic version of this article is the complete one and can be found online at:

Published: June 13, 2005

© 2005 Schablowski et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.




Navigation is becoming increasingly important in knee-endoprostheses. The objective of this prospective study was to examine the results of a CT-free navigation system in arthroplasty of the knee joint. The possible advantages or disadvantages of this computer-assisted method were to be determined in comparison with conventional implantation. In addition, the practicability of the system in the operating theater was evaluated.


Between December 2002 and December 2003 implantation of the endoprosthesis was navigated in 80 patients and performed conventionally in another 80. The Natural-Knee-II-Prosthesis manufactured by Centerpulse was used as the prosthesis model in all cases. The Navitrack®-System manufactured by the same company was used for the navigation-assisted prosthesis implantation. The precision attained in component placement was checked by standardized X-ray images. The knee joint function, the activity level and the patient's quality of life were evaluated using the Knee Society Score. In addition, both procedures were compared with respect to time required, complications and clinical practicability.


Initial difficulties in using the navigation system were overcome during a short introductory period. The OP-times could be shortened, whereby however, two additional surgical steps (placement of the infrarot pins) result in a highly-significantly longer total operating time compared to conventional implantation. Analysis of the X-ray images revealed no significant difference between the groups with respect to the mechanical axis. However, the variance in the navigation group was significantly less. Analysis of other axis parameters revealed also considerably less scattering in the navigation group than in the conventional implantation group.


he Navitrack® is a relatively simple system, since no CT or MRT data are required and no preoperative planning phase is necessary. The disadvantage of the additional time required in the CT-free navigation of a knee endoprosthesis is offset by the safer and more exact placement of the components.