Measurement of femoral axial offset

Abstract

Purpose to examine the accuracy and reproducibility of the femoral axial offset measured from the retrocondylar plane by computed tomography (CT). Bone specimens of the femur of 15 males and 15 females were analyzed. CT imaging was performed and data of the coordinates were collected (center of femoral head, center of an ellipse around greater trochanter, center of an ellipse around the base of femoral neck, posterior edge of great trochanter, and both posterior condyles). The angle between the line connecting center of the femoral head and center of an ellipse around greater trochanter and the line connecting both posterior condyles was set as anteversion 1. The angle between the line connecting the center of femoral head and center of an ellipse around base of the femoral neck and the line connecting both posterior condyles was set as anteversion 2. The femoral axial offset was measured from the retrocondylar plane. Measurements were performed three times on the same subject, and intrarater reliability (ICC) was determined. In addition, interrater reliability (ICC) was determined by comparing data from three raters. The mean value for anteversion 1 was 20.1° for males and 22.7° for females. The values for anteversion 2 were 16.0° and 19.9° for males and females, respectively. Offset was 34.0 and 33.4 mm in males and females, respectively. Intrarater ICC and interrater ICC exceeded 0.81 for both methods, suggesting that the method of measurement was reliable. Accuracy and reproducibility of the measurement of femoral axial offset from the retrocondylar plane were high.

The Sum of the Leg Length Discrepancy and the Difference in Global Femoral Offset Is Equal to That of the Contralateral Intact Side and Improves Postoperative Outcomes after Total Hip Arthroplasty: A Three-Dimensional Analysis

“…It was placed using a mechanical guide [ 18 ] or CT-based navigation [ 19 ], according to the pre-operative planning; the accuracy of the implantation was described within 3° in both devices [ 18 , 19 ]. The stem was inserted at an angle of 20–25° at the anteversion relative to the posterior condylar plane, containing the most posterior ends of the bilateral femoral condyles and greater trochanter [ 20 ]. It was applied to the shape of the femoral shaft’s medullary canal to fit the medial and lateral femoral shafts aimed to restore the offset and LLD and adjusted using the combined anteversion theory [ 21 , 22 ].…”

The association of postoperative global femoral offset with total hip arthroplasty outcomes

“…This preserves the individual sagittal inclination of the anterior pelvic plane (APP), the plane including the most anterior point of the pubic symphysis and bilateral anterior superior iliac spine in the supine position. The stem was placed at 20°–25° anteversion relative to the retrocondylar plane (the plane including the most posterior points of the greater trochanter and bilateral femoral condyles) 10 and was adjusted to the shape of the medullary canal of the femoral shaft using the combined anteversion theory 11 , 12 . This study was approved by the Institutional Review Board of Niigata University Graduate School of Medical and Dental Sciences (2019-0051).…”