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Advances in Orthopedics
Volume 2016 (2016), Article ID 2606453, 7 pages
Research Article

Reliable Alignment in Total Knee Arthroplasty by the Use of an iPod-Based Navigation System

1Department of Orthopaedics, Trauma Surgery and Sports Medicine, Cologne Merheim Medical Center, Witten/Herdecke University, 51109 Cologne, Germany
2Department of Orthopaedic Surgery, Schulthess Clinic, 8008 Zurich, Switzerland

Received 10 January 2016; Revised 9 May 2016; Accepted 10 May 2016

Academic Editor: Panagiotis Korovessis

Copyright © 2016 Paola Koenen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Axial alignment is one of the main objectives in total knee arthroplasty (TKA). Computer-assisted surgery (CAS) is more accurate regarding limb alignment reconstruction compared to the conventional technique. The aim of this study was to analyse the precision of the innovative navigation system DASH® by Brainlab and to evaluate the reliability of intraoperatively acquired data. A retrospective analysis of 40 patients was performed, who underwent CAS TKA using the iPod-based navigation system DASH. Pre- and postoperative axial alignment were measured on standardized radiographs by two independent observers. These data were compared with the navigation data. Furthermore, interobserver reliability was measured. The duration of surgery was monitored. The mean difference between the preoperative mechanical axis by X-ray and the first intraoperatively measured limb axis by the navigation system was 2.4°. The postoperative X-rays showed a mean difference of 1.3° compared to the final navigation measurement. According to radiographic measurements, 88% of arthroplasties had a postoperative limb axis within ±3°. The mean additional time needed for navigation was 5 minutes. We could prove very good precision for the DASH system, which is comparable to established navigation devices with only negligible expenditure of time compared to conventional TKA.