Interindividuelle Streuung der femoralen Rotationsachsen am Kniegelenk - eine Achsvermessung anhand von Dünnschicht-Computertomographien

Abstract

Title: The rotational alignment of the femoral component in TKA - a comparison of bone based alignment methods by doing measurements with help of computed tomographies. Subject: Aim of the study has been the measurement of the spreading of the different axes to each other, which are used to determine the rotational alignment of the femoral component in TKA. Methodology: In 95 long leg computed tomography scans digital multi-dimensional controlled marking of anatomic landmarks is performed. Out of these markings the ap axis, the epicondylar axis, the posterior condylar axis and the correlating angles are measured and visualized by a calculating software. Results: The maximum range between the epicondylar axis und the posterior condyle axis is between 0,7° / 19,8° (min / max), average 6,3° and SD ± 2,7°. The maximum range between the the epicondylar axis and ap axis is between 78,3° / 101,2° (min / max), average value of 87,6° and SD ± 4,6°. The maximum range between the ap axis and posterior condylar axis is between 76,6° / 93,6° (min / max), average value of 83,4° and SD ± 3,7°. In varus axes the ranges are higher as in comparison to normal or valgus axes. A gender specific difference concerning the range of the axes to each other couldn´t be pointed out. Conclusion: Regarding the immense ranges, also considering the deviation of leg axes and gender it is obvious that no recommendation can be given concerning to one specific alignment method. All alignment methods using bony landmarks serve in many patients the possibility to give satisfying femoral rotational results. The remarkable inter individual range of values requires high experience in orientating the femoral component in correct rotation.