N° 003 - September / October 2019
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Adjusted mechanical alignment to achieve a well-balanced knee with less soft tissue releases: Surgical tips and tricks for a modified “extension gap first technique” in TKA
By Hagen Hommel (1,2), Peter Fennema (3) in category
(1). KH-MOL GmbH Sonnenburger Weg 3, 16269 Wriezen, Germany (2). Medizinische Hochschule Brandenburg (MHB), Theodor Fontane, Fehrbelliner Straße 38, 16816 Neuruppin, Germany - (3). AMR Advanced Medical Research GmbH, Hofenstrasse 89b, 8708 Männedorf, Switzerland / Email: [email protected]
In total knee arthroplasty (TKA), one of the primary goals has been a well-balanced stable knee with a neutrally aligned lower limb because this has been considered to be necessary for positive clinical outcomes and implant survivorship . Mechanical alignment (MA) technique for TKA aims to systematically create a “biomechanically friendly prosthetic knee” rather than restore the constitutional patient-specific anatomy [1,2]. MA technique has three aims. The first aim is to create a neutral frontal limb mechanical axis with the femorotibial joint line perpendicular to this mechanical axis. The second aim is to align the femoral component parallel to the trans-epicondylar axis (TEA) in the axial plane. Third, the MA technique aims to align the extensor mechanism to the components in all three planes . It has been recommended that this implant positioning prevents patella instability and maltracking, early implant loosening and accelerated polyethylene wear because it generates less and more-evenly-distributed stress inside the joint and at the bony interfaces . This concept aims for a “systematic target” rather than a restoration of the patient anatomy, and it can therefore be defined as the “systematic approach for TKA implantation” .
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