scholarly journals Femoral Torsion in CT: Why We Should Add Some Trigonometry

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Magerkurth O ◽  
◽  
Konig F ◽  
Rutz E ◽  
Falkowski AL ◽  
...  
Keyword(s):  
Femoral Neck ◽  
Femoral Anteversion ◽  
Femoral Torsion ◽  
Final Formula ◽  
Accuracy Of Measurements ◽  
Correct Alignment ◽  
Magnetic Resonance Imaging Mri ◽  
Oblique Images ◽  
Precise Assessment ◽  
Initial Measurement

Purpose: In our department, we routinely perform Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) of the lower extremity to assess femoral torsion for preoperative planning prior correcting osteotomies. It might be difficult to assess the FA, because on axial images the depicted part of the femoral neck is too short to allow correct alignment of the axis of the femoral neck. Measurements can also be performed on oblique axial images with improvement of depiction of the femoral neck but are smaller than those of measurements on axial images, due to the fact that images depend on rules of trigonometry. The aim is to provide a trigonometrical formula to calculate the value for FA, allowing precise assessment of femoral anteversion on oblique axial images similar to those on axial images. Materials and Methods: Trigonometrical transformation is performed in three steps. Initial measurement of femoral anteversion on oblique images is transformed via a corresponding rectangular triangle from coronal images to calculated femoral anteversion on axial images. Results: The first triangle is labelled with a1, b1, c1 for the sides and alpha1, beta1for the angles. Second and third triangle is labelled correspondingly. Length of both cathetus a1 and b1 are calculated as follows: cathetus a1=sin alpha1*c1 and cathetus b1=cos alpha 1*c1. Cathetus b2 is calculated as follows: b2=cos alpha2*c2. alpha3=tan-1 (a3/b3). Initial calculation of angle alpha3=tan-1 (a3/b3)=tan-1 (a1/b2), with a3=a1=sin alpha1*c1 and b3=b2=cos alpha2*b1*c, with b1=cos alpha1*c1 and b3=cos alpha2*cos alpha1*c1². The final formula is then: alpha3=tan-1 ((sin alpha1*c1)/(cos alpha²*cos alpha1*c12)) = tan-1 ((sin alpha1/(alpha2*cos alpha1*c1)) Conclusion: In this study we can provide a formula: alpha3=tan-1 ((sin alpha1/(cos alpha2*cos alpha1*c1)), which allows to calculate the femoral anteversion for true axial reconstructed images with the increased accuracy of measurements on oblique images and the ability to use the already known reference values from the literature.

The walls of the femoral neck as an auxiliary tool for femoral stem positioning

2021 ◽  
pp. 112070002110407
Author(s):  
Samuel Morgan ◽  
Ofer Sadovnic ◽  
Moshe Iluz ◽  
Simon Garceau ◽  
Nisan Amzallag ◽  
...  
Keyword(s):  
Femoral Neck ◽  
Accurate Determination ◽  
Femoral Stem ◽  
Posterior Wall ◽  
Anterior Wall ◽  
Femoral Anteversion ◽  
Lower Limbs ◽  
Imaging Analysis ◽  
Femoral Condyles

Background: Femoral anteversion is a major contributor to functionality of the hip joint and is implicated in many joint pathologies. Accurate determination of component version intraoperatively is a technically challenging process that relies on the visual estimation of the surgeon. The following study aimed to examine whether the walls of the femoral neck can be used as appropriate landmarks to ensure appropriate femoral prosthesis version intraoperatively. Methods: We conducted a retrospective study based on 32 patients (64 hips) admitted to our centre between July and September 2020 who had undergone a CT scan of their lower limbs. Through radiological imaging analysis, the following measurements were performed bilaterally for each patient: anterior wall version, posterior wall version, and mid-neck femoral version. Anterior and posterior wall version were compared and evaluated relative to mid-neck version, which represented the true version value. Results: Mean anterior wall anteversion was 20° (95% CI, 17.6–22.8°) and mean posterior wall anteversion was −12° (95% CI, −15 to −9.7°). The anterior walls of the femoral neck had a constant of −7 and a coefficient of 0.9 (95% CI, −9.8 to −4.2; p  < 0.0001; R2 0.77). The posterior walls of the femoral neck had a constant of 20 and a coefficient of 0.7 (95% CI, 17.8–22.5; p  < 0.0001; R2 0.60). Conclusions: Surgeons can accurately obtain femoral anteversion by subtracting 7° from the angle taken between the anterior wall and the posterior femoral condyles or by adding 20° to the angle taken between the posterior wall and the posterior femoral condyles.

scholarly journals Sex Difference in Hip Adduction during Running: Influence of Hip Abductor Strength, Activation, and Pelvis & Femur Morphology

2021 ◽  
Author(s):  
Jia Liu ◽  
Kristi L. Lewton ◽  
Patrick M. Colletti ◽  
Christopher M. Powers
Keyword(s):  
Sex Differences ◽  
Femoral Neck ◽  
Muscle Activation ◽  
Femoral Anteversion ◽  
Femur Length ◽  
Computed Tomography Scanning ◽  
Hip Abductor ◽  
Independent Variable ◽  
Tomography Scanning ◽  
Abductor Strength

Purpose: To examine the influence of hip abductor strength, neuromuscular activation, and pelvis &amp; femur morphology in contributing to sex differences in hip adduction during running.Methods: Fifteen female and 14 male runners underwent strength testing, instrumented overground running (e.g., kinematics and muscle activation), and computed tomography scanning of pelvis and femur. Morphologic measurements included bilateral hip width to femur length ratio, acetabulum abduction, acetabulum anteversion, femoral anteversion, and femoral neck-shaft angles. Sex differences for all variables were examined using independent t-tests. Linear regression was used to assess the ability of each independent variable of interest to predict peak hip adduction during the late swing and stance phase of running. Results: Compared to males, females exhibited significantly greater peak hip adduction during both late swing (8.5 ± 2.6° vs 6.2 ± 2.8°, p = 0.04) and stance phases of running (13.4 ± 4.2° vs 10.0 ± 3.2°, p = 0.02). In addition, females exhibited significantly lower hip abductor strength (1.8 ± 0.3 vs 2.0 ± 0.3 Nm/kg, p=0.04), greater femoral neck-shaft angles (134.1 ± 5.0° vs 129.9 ± 4.1°, p=0.01), and greater hip width to femur length ratios than males (0.44 ± 0.02 vs 0.42 ± 0.03, p=0.03). Femoral anteversion was the only significant predictor of peak hip adduction during late swing (r=0.36, p=0.05) and stance (r=0.41, p=0.03).Conclusion: Our findings highlight the contribution of femur morphology as opposed to hip abductor strength and activation in contributing to hip adduction during running.

scholarly journals Complications of hip preserving surgery

2021 ◽  
Vol 6 (6) ◽  
pp. 472-486
Author(s):  
Markus S. Hanke ◽  
Till D. Lerch ◽  
Florian Schmaranzer ◽  
Malin K. Meier ◽  
Simon D. Steppacher ◽  
...  
Keyword(s):  
Treatment Plan ◽  
Periacetabular Osteotomy ◽  
Preoperative Evaluation ◽  
Femoral Torsion ◽  
Labral Tears ◽  
Hip Preserving Surgery ◽  
Technical Advances ◽  
Additional Imaging ◽  
Magnetic Resonance Imaging Mri ◽  
The Individual

Preoperative evaluation of the pathomorphology is crucial for surgical planning, including radiographs as the basic modality and magnetic resonance imaging (MRI) and case-based additional imaging (e.g. 3D-CT, abduction views). Hip arthroscopy (HAS) has undergone tremendous technical advances, an immense increase in use and the indications are getting wider. The most common indications for revision arthroscopy are labral tears and residual femoroacetabular impingement (FAI). Treatment of borderline developmental dysplastic hip is currently a subject of controversy. It is paramount to understand the underlining problem of the individual hip and distinguish instability (dysplasia) from FAI, as the appropriate treatment for unstable hips is periacetabular osteotomy (PAO) and for FAI arthroscopic impingement surgery. PAO with a concomitant cam resection is associated with a higher survival rate compared to PAO alone for the treatment of hip dysplasia. Further, the challenge for the surgeon is the balance between over- and undercorrection. Femoral torsion abnormalities should be evaluated and evaluation of femoral rotational osteotomy for these patients should be incorporated to the treatment plan. Cite this article: EFORT Open Rev 2021;6:472-486. DOI: 10.1302/2058-5241.6.210019

Distal femoral morphological dysplasia is correlated with increased femoral torsion in patients with trochlear dysplasia and patellar instability

2020 ◽  
Vol 102-B (7) ◽  
pp. 868-873
Author(s):  
Guangmin Yang ◽  
Yike Dai ◽  
Conglei Dong ◽  
Huijun Kang ◽  
Jinghui Niu ◽  
...  
Keyword(s):  
Patellar Instability ◽  
Trochlear Dysplasia ◽  
Femoral Condyle ◽  
Pearson Correlation ◽  
Femoral Anteversion ◽  
Lateral Condyle ◽  
Anteversion Angle ◽  
Medial Condyle ◽  
Femoral Torsion ◽  
Condylar Morphology

Aims The purpose of this study was to explore the correlation between femoral torsion and morphology of the distal femoral condyle in patients with trochlear dysplasia and lateral patellar instability. Methods A total of 90 patients (64 female, 26 male; mean age 22.1 years (SD 7.2)) with lateral patellar dislocation and trochlear dysplasia who were awaiting surgical treatment between January 2015 and June 2019 were retrospectively analyzed. All patients underwent CT scans of the lower limb to assess the femoral torsion and morphology of the distal femur. The femoral torsion at various levels was assessed using the a) femoral anteversion angle (FAA), b) proximal and distal anteversion angle, c) angle of the proximal femoral axis-anatomical epicondylar axis (PFA-AEA), and d) angle of the AEA–posterior condylar line (AEA-PCL). Representative measurements of distal condylar length were taken and parameters using the ratios of the bianterior condyle, biposterior condyle, bicondyle, anterolateral condyle, and anteromedial condyle were calculated and correlated with reference to the AEA, using the Pearson Correlation coefficient. Results The femoral torsion had a strong correlation with distal condylar morphology. The FAA was significantly correlated with the ratio of the bianterior condyle (r = 0.355; p = 0.009), the AEA-PCL angle (r = 0.340; p = 0.001) and the ratio of the anterolateral condyle and lateral condyle (ALC-LC) (r = 0.309; p = 0.014). The PFA-AEA angle was also significantly correlated with the ratio of the bianterior condyle (r = 0.319; p = 0.008), the AEA-PCL angle (r = 0.231; p = 0.031), and the ratio of ALC-LC (r = 0.261; p = 0.034). In addition, the bianterior condyle ratio showed a significant correlation with the biposterior condyle ratio (r = -0.324; p = 0.027) and the AEA-PCL angle (r = 0.342; p = 0.021). Conclusion Increased femoral torsion correlated with a prominent anterolateral condyle and a shorter posterolateral condyle compared with the medial condyle. The deformities of the anterior and posterior condyles are combined deformities rather than being isolated and individual deformities in patients with trochlear dysplasia and patella instability. Cite this article: Bone Joint J 2020;102-B(7):868–873.

CT Measurement of Anteversion in the Femoral Neck

1997 ◽  
Vol 38 (4) ◽  
pp. 527-532 ◽  
Author(s):  
K. L. Hermann ◽  
N. Egund
Keyword(s):  
Clinical Practice ◽  
Femoral Neck ◽  
Measurement Accuracy ◽  
Femoral Shaft ◽  
Femoral Anteversion ◽  
Intraobserver Variability ◽  
Actual Position ◽  
Measurement Concept ◽  
The Mean ◽  
Ct Measurement

Purpose: To evaluate CT methods of measuring anteversion in the femoral neck with respect to measurement accuracy and with respect to the influence exerted by different femoral shaft positions; and to describe a new CT measurement concept that introduces a mathematical adjustment for different femoral shaft positions. The new technique facilitates the taking of measurements in patients who cannot be correctly positioned in traditional methods. Material and Methods: CT examinations of previously measured anteversions in the femoral neck were reviewed in retrospect in 30 patients with fractures of the femoral neck. The position of the femoral shaft was assessed. A reference angle was compared with direct traditional measurements and with measurements adjusted for the actual position of the femoral shaft by means of a 3D mathematical reconstruction. Reproducibility and inter— and intraobserver variability were assessed in 10 cases. Results: All femurs varied in position within the gantry. The mean difference between the direct CT measurement and the adjusted CT measurement compared to the reference angle were -8.8° (range -35.0-16.3°) and -0.1° (range -1.4-1.4°), respectively. For the adjusted CT method, reproducibility and inter- and intraobserver variability were 1.4 intraobserver variability were 1.4, 1.6 intraobserver variability were 1.4 and 1.4° (SD of difference), respectively. Conclusion: CT measurement of femoral anteversion in clinical practice can only be accurate when corrected for variation in the position of the femoral shaft.

scholarly journals Locating the Origin of Femoral Maltorsion Using 3D Volumetric Technology—The Hockey Stick Theory

2020 ◽  
Vol 9 (12) ◽  
pp. 3835
Author(s):  
Joan Ferràs-Tarragó ◽  
Vicente Sanchis-Alfonso ◽  
Cristina Ramírez-Fuentes ◽  
Alejandro Roselló-Añón ◽  
Francisco Baixauli-García
Keyword(s):  
Femoral Neck ◽  
Longitudinal Axis ◽  
Femoral Anteversion ◽  
Mirror Image ◽  
Femoral Diaphysis ◽  
P Value ◽  
Rotational Axis ◽  
Atypical Case ◽  
Derotational Osteotomy ◽  
Lineal Regression

Background: The origin of femoral maltorsion is often unknown. However, defining the origin of the rotation of the femoral maltorsion can be useful for establishing the most suitable point to do an external derotational osteotomy. Previous studies have not considered the femoral diaphysis in their investigations of the origin of the deformity. The study of the whole morphology of the femur with 3D volumetric tools, including the femoral diaphysis can contribute to a better understanding of the behavior of femoral maltorsion. Methods: An atypical case of unilateral femoral anteversion was selected. Both femurs were used to obtain 3D bio-models. The mirror image of the asymptomatic side was obtained and overlapped with the symptomatic femur. The Hausdorff–Besicovitch method was used to evaluate the morphologic discrepancies (in mm) between the two femurs in three zones: (1) the femoral neck, (2) the proximal diaphysis, and (3) the distal diaphysis. The differences between the two femurs were analyzed and its correlation was statistically defined using a lineal regression model. Results: The deformity in the distal diaphysis increased from the supracondylar area until the apex of the antecurvatum angle (R2 = 0.91) and then decreased until the base of the femoral neck (R2 = (−0.83)), to finally increase significantly in the femoral neck area (R2 = 0.87). All of the correlations were statistically significant (p-value ˂ 0.001). Conclusion: The femoral maltorsion originates in the supracondylar area and its rotational axis is the longitudinal axis of the femoral diaphysis. Even though the deformity affects the femoral diaphysis, its clinical relevance is much higher in the femoral neck since the rotational axis passes through its base. Thus, the osteotomy can be conducted along all of the femoral diaphysis as long as it is done perpendicular to it.

Ultrasonographic Assessment of Femoral Torsion Angle Based on Tilting Angles of Femoral Neck and Condylar Axis

2019 ◽  
Vol 45 (8) ◽  
pp. 1970-1976
Author(s):  
Satoshi Takeuchi ◽  
Hideyuki Goto ◽  
Hirotaka Iguchi ◽  
Nobuyuki Watanabe ◽  
Satoshi Osaga ◽  
...  
Keyword(s):  
Femoral Neck ◽  
Torsion Angle ◽  
Femoral Torsion ◽  
Ultrasonographic Assessment

Intra-articular Lesions: Imaging and Surgical Correlation

2017 ◽  
Vol 21 (05) ◽  
pp. 487-506 ◽  
Author(s):  
Inga Todorski ◽  
Till Lerch ◽  
Joseph Schwab ◽  
Jennifer Cullmann-Bastian ◽  
Moritz Tannast ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Cartilage Damage ◽  
Preoperative Assessment ◽  
Pattern Size ◽  
Tear Pattern ◽  
Magnetic Resonance Imaging Mri ◽  
Direct Magnetic Resonance Arthrography ◽  
Oblique Images ◽  
Small Field Of View

AbstractThe past 2 decades have seen a substantial increase in hip joint preserving procedures, primarily secondary to not only hip dysplasia, but the recognition and description of femoroacetabular impingement (FAI), and its association with chondral lesions, as a potentially pre-arthritic condition. Morphological magnetic resonance imaging (MRI) plays an essential role in the preoperative assessment of osseous deformities and in particular of the resulting joint degeneration. An accurate descriptive report of chondrolabral lesions is warranted describing the tear pattern, size, localization, and extension of the lesions. This is important because different damage patterns and localization of the lesions may determine the surgical approach. The current imaging standard is direct magnetic resonance arthrography (MRA) with a small field of view, with acquisition of radial images in addition to the classic coronal, sagittal, and axial-oblique images. Early cartilage damage detected on direct MRA obtained with or without traction can predict long-term failure after FAI surgery.

The accuracy of measurements of femoral neck fractures

1992 ◽  
Vol 63 (2) ◽  
pp. 152-156 ◽  
Author(s):  
JÓN I. Ragnarsson ◽  
Paul Eliasson ◽  
Johan Kärrholm ◽  
Bo Lundström
Keyword(s):  
Femoral Neck ◽  
Femoral Neck Fractures ◽  
Accuracy Of Measurements
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