genALIGN^M - Implementation and Evaluation of a novel Instrument for minimal-invasive Total Knee Arthroplasty

Objectives

Determination of the mechanical femoral axis for prosthesis alignment in Total Knee Arthroplasty (TKA) based on purely mechanical force-torque-measurement.
Less invasive and more accurate than intramedullary alignment guides and lower-cost than computer assisted navigation systems.
Compared to the electronic system currently developed in the OrthoMIT project, no additional peripheral devices such as evaluation electronics, PC and monitor, reduced costs and simplified sterilization process.
Optimization of the system with regard to usability and risk management.

The surgeon applies a compressive force to the knee using the genALIGN device.
Resulting shear forces and torques are directly displayed to the surgeon by mechanical means.
When these forces and torques become zero, the device is aligned with the mechanical femur axis.

The Project genALIGN^M is funded by the European Union as part of the European Regional Development Fund.
(Project term: 4/2009-6/2011)

F. Zimmermann, C. Schwenninger, U. Nolten, F.P. Firmbach, R. Elfring & K. Radermacher: A new approach to implant alignment and ligament balancing in total knee arthroplasty focussing on joint loads. Biomed Tech (Berl), 2012, 57(4), pp. 283-291
F. Zimmermann: Implantatpositionierung und Weichteilbalancing der Knieprothese unter Fokussierung auf die Gelenkbelastung, Deutscher Kongress für Orthopädie und Unfallchirurgie, 23.-26. Oktober, 2012, eingeladener Vortrag
F. Zimmermann, M. Asseln, B. Rath & K. Radermacher: Three challenges of TKA – one force-torque-based solution: the genALIGN system. 13th Annual Meeting of the International Society for Computer Assisted Orthopaedic Surgery, 2013, pp. 192-193
US Patent No. 8308730 erteilt – Method of and apparatus for determining the mechanical axis of a femur – Nov 2012