Complications of fixed infrared emitters in computer-assisted total knee arthroplasties.
BACKGROUND
The first stage in the implant of a total knee arthroplasty with computer-assisted surgery is to fasten the emitters to the femur and the tibia. These trackers must be hard-fixed to the bone. The objectives of our study are to evaluate the technical problems and complications of these tracker-pins, the necessary time to fix them to the bone and the possible advantages of a new femoral-fixed tracker-pin.


METHODS
Three hundred and sixty seven tracker-pins were used in one hundred and fifty one computer-assisted total knee replacements. A bicortical screw was used to fix the tracker to the tibia in all cases; in the femur, however, a bicortical tracker was used in 112 cases, while a new device (OrthoLock) with percutaneous fixation pins was employed in the remaining 39.


RESULTS
Technical problems related to the fixing of the trackers appeared in nine cases (2.5%). The mean surgery time to fix the tracker pin to the tibia was 3 minutes (range 2-7), and 5 minutes in the case of the femoral pin (range: 4-11), although with the new tool it was only three minutes (range 2-4) (p < 0.001). No complications were observed with this new device.


CONCLUSIONS
The incidence of problems and complications with the fixing systems used in knee navigation is very small. The use of a new device with percutaneous pins facilitates the fixing of femoral trackers and decreases the time needed to place them.
Hernández-Vaquero
Daniel
D
Department of Orthopaedic Surgery, Hospital San Agustin, Avilés School of Medicine, University of Oviedo, Spain. dhernandezv@meditex.es
Suárez-Vázquez
Abelardo
A
D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods; D001863:Bone Screws / Q000592:standards*; D006801:Humans; D007259:Infrared Rays; D007431:Intraoperative Complications / Q000453:epidemiology* / Q000517:prevention & control; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods