Article

Identification of the center of the femoral head in the
coronal plane is essential during total knee arthroplasty. We evaluated a new
method for localization of the center of the hip, thereby detecting the neutral
mechanical axis using inter-femoral head center distances (X) measured from a
radiograph. Our proposed method was compared with 3 commonly used methods using
landmarks that are estimated to be 2 finger-breaths medial to the anterosuperior
iliac spine (method A), 2.5 cm perpendicular to the mid-inguinal point (method
I), and 1.5 cm lateral to the femoral artery (method F). METHODS: 114 patients
undergoing total knee arthroplasty were prospectively enrolled in the study. Four
landmarks were marked and conventional anterior-posterior pelvic radiographs were
taken. On the radiograph, the distance between the estimated FHC and the neutral
mechanical axis was measured. RESULTS: The median value (mm) of the measured
distance was 9 in A, 7 in I, 8.5 in F, and 5 in X. When an error of more than 3
degrees from neutral alignment was defined as an outlier, 15% of measurements in
A, 6% of measurements in I, 14% in F, and 2% in X would fall in the outlier zone.
INTERPRETATION: The method detecting the neutral mechanical axis using
inter-femoral head center distances (X) showed the least variability and the
lowest percentage of outliers.

Langue : ANGLAIS