Abstract
Aims: The purpose of this study was to þnd out if an open navigation system is useful in early revision cases of TKA. We used an open navigation device which was developed in our hospital. The question was to þnd out if the mal positioning of the implants can be analyzed by the navigation device. Methods: 41 early revision cases were performed with the support of our navigation device. All these cases came to the hospital because of pain or swelling, there was now infection and now loosening in this group. We analyzed the positioning of the implant by cinematic navigation that means pre-operative CT and other preparations were not necessary. We measured the position of the implants and compared it to the ideal position which was calculated by the navigation device. Results: The need of early revision in total knee arthroplasty is caused by mal-positioning of the implants. The mal-positioning leads to a mal alignment and to a soft tissue imbalance. The most common failure in Germany is a wrong internal rotation of the femur component. This is causing overload of the medium side of the polyethylene and an instability of the lateral side. Often mal tracking of the patella is caused by mal rotation of the femur component. In all these cases the navigation device could lead the surgeon to the right position of the implant in revision surgery. Conclusions: A development of open navigation systems is necessary for the use of these systems in revision surgery. Revision surgery needs from time to time the intraoperative calculation of the positioning because early revisions are always caused by mal alignments. Therefore the use of a navigation device can improve the knowledge of the surgeon and help to perform the revision surgery in an excellent way.
Theses abstracts were prepared by Professor Dr. Frantz Langlais. Correspondence should be addressed to him at EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
