Computed Tomography in the Measurement of Femoral Anteversion

Weiner, Dennis S.; Cook, Albert J.; Hoyt, Walter A.; Oravec, C. E.; Kuhns, Lawrence R.

doi:10.1097/00004728-197904000-00050

Cited by 66 publications

(113 citation statements)

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“…Later, Weiner et al described a method for measuring total femoral torsion in CT [17]. Currently, in clinical practice total femoral torsion is determined in the transverse plane between the femoral neck (proximal femur) and the posterior condylar line (distal femur) [18].…”

Section: Discussionmentioning

confidence: 99%

Segmental torsion assessment is a reliable method for in-depth analysis of femoral alignment in Computer Tomography

Ferlic

Runer

Seeber

et al. 2017

International Orthopaedics (SICOT)

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Purpose De-rotational osteotomies are indicated in patients with pathologic femoral torsion. However, there is disagreement whether an osteotomy should be performed proximally or distally. Conventionally only the total torsion is measured, which does not allow differentiation between a torsional deformity located in the proximal or distal metaphysis or the diaphysis. The aim of this study is to validate a new multilevel measurement protocol for evaluation of the magnitude of torsion of the respective femoral segments in CT. Patients and methods The torsional profile of 30 femora was evaluated in CT scans. For separate measurements of the torsion of the metaphysis and the diaphysis, four axes where determined: one through the femoral neck, a second determined by the midpoint of the femoral shaft and the lesser trochanter, a third determined by a tangent dorsal to the popliteal surface, and a fourth axis posterior to the condyles. The total femoral torsion was measured between the first and the fourth axis, proximal torsion between the first and the second, mid torsion between the second and the third, and distal torsion between the third and the fourth axis. Four investigators performed all measurements independently and intraclass correlation coefficients (ICC) were calculated to evaluate intra-and inter-rater reliability. Results Average total femoral torsion was 22.6 ± 8.7°, proximal torsion 47.7 ± 10.6°, mid torsion −33.4 ± 9.9°, and distal torsion 8.3 ± 3.2°. Intra-rater ICC ranged between 0.504 and 0.957 and inter-rater ICC between 0.643 and 0.992. The majority of the ICC were graded as Balmost perfect^and some as Bsubstantial^agreement. Conclusion Evaluation of the segmental torsion of the femur allows in-depth analysis of femoral alignment. High reliability was shown for this measuring method in computed tomography, which can be deployed when studying interdependencies between joint pathologies and torsional deformities or when planning the site for an osteotomy. Level of evidence Level III.

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Section: Discussionmentioning

confidence: 99%

Segmental torsion assessment is a reliable method for in-depth analysis of femoral alignment in Computer Tomography

Ferlic

Runer

Seeber

et al. 2017

International Orthopaedics (SICOT)

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“…Before the advent of CT, both direct [5] and indirect [2, 11-13, 15, 17] plain radiographic techniques were used to characterize femoral rotation. CT allowed for direct superimposition of a single neck and condylar axis, which remains the basis for most measurements to this day [18]. However, the femoral neck is neither uniplanar nor cylindrical and can be best approximated by a series of ellipses that create a unique composite neck axis, which deviates from the shaft axis by an average 5 mm and the center of the femoral head by 2.5 mm [3].…”

Section: Discussionmentioning

confidence: 99%

“…The ''traditional'' method described by Weiner et al [18] incorporated the femoral neck axis from a single axial image and a single posterior condylar axis. The posterior condylar axis provides the most accurate and reproducible distal reference point [10].…”

Section: Methodsmentioning

confidence: 99%

Can Femoral Rotation Be Localized and Quantified Using Standard CT Measures?

Georgiadis

Siegal

Scher

et al. 2015

Clinical Orthopaedics &Amp; Related Research

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Background The terms ''femoral anteversion'' and ''femoral torsion'' have often been used interchangeably in the orthopaedic literature, yet they represent distinct anatomical entities. Anteversion refers to anterior tilt of the femoral neck, whereas torsion describes rotation of the femoral shaft. Together, these and other transverse plane differences describe what may be considered rotational deformities of the femur. Assessment of femoral rotation is now routinely measured by multiple axial CT methods. The most widely used radiographic technique (in which only two CT-derived axes are made, one through the femoral neck and one at the distal femoral condyles) may not accurately quantify proximal femoral anatomy nor allow identification of the anatomic locus of rotation. Questions/purposes (1) What CT methodology (a twoaxis CT-derived technique, a three-axis technique adding an intertrochanteric axis-the ''Kim method,'' or a volumetric three-dimensional reconstruction of the proximal femur) most accurately quantifies transverse plane femoral morphology; (2) localizes those deformities; and (3) is most reproducible across different observers? Methods We constructed a high-definition femoral sawbones model in which osteotomies were performed at either the intertrochanteric region or femoral shaft. Transverse plane deformity was randomly introduced and CTderived rotational profiles were constructed using three different CT methods. Accuracy and consistency of measurements of femoral rotation were calculated using p values and Fisher's exact test and intraclass correlation coefficients (ICCs). Results All three CT methodologies accurately quantified overall transverse plane rotation (mean differences 0.69°± 3.88°, 0.69°± 3.88°, and À1.09°± 4.44°for the two-plane, Kim, and volumetric methods, respectively). However, use of a single neck and single distal femoral axis does not reliably identify the anatomic locus of rotation, whereas the Kim and volumetric methods do (p \ 0.0001). All three methods were highly reproducible between observers (ICCs of 0.9569, 0.9569, and 0.9359 for the traditional two-plane, Kim, and volumetric methods, respectively). Conclusions Only the Kim and volumetric methods can identify the anatomic location of transverse plane rotation and we recommend using one of the two techniques. Accurate anatomic localization of transverse plane rotation

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“…Accurate measurement of the AV angle can be obtained by computed tomography (CT) (Weiner et al 1978, Peterson et al 1981. However, exposure to radiation is a disadvantage associated with all radiographic methods, including CT.…”

Section: Femoral Anteversion In Children Measured By Ultrasound Terjementioning

confidence: 99%