The functional knee joint axis - a reproducible femoral rotation landmark in navigated knee arthroplasty

摘要

Introduction: The correct rotation of the femoral component is of crucial importance to the functional outcome [Romero]. Several landmarks are currently considered to determine the rotational alignment of the femoral component (epicondylar axis, Whiteside Line, dorsal condylar axis). However, these landmarks are determined with only limited accuracy and reproducibility [Fuiko / Eckhoff / Enrike / Jenny]. In minimally invasive surgical approaches it is impossible to palpate both epicondyles simultaneously, so that landmarks leading to a less accurate determination of femoral rotation have to be used. Navigation provides the ability to directly and intraoperatively determine the knee kinematics and use the information to establish the rotation of the femoral component, without taking a detour via the rather error-prone bony landmarks. The objective of the study is to compare the functional knee axis data to the current gold standard, and determine the applicability of a new knee axis algorithm.