A 45-Degree Radiographic Method for Measuring the Neck Shaft Angle and Anteversion of the Femur: A Pilot Study

Abstract

ABSTRACTpurpose. To propose a novel method to measure the neck shaft angle and anteversion of the femur using anteroposterior and 45º oblique radiographs. Methods. Three human subjects were used to verify the 45º oblique method. The true neck shaft angle and anteversion of the femur were determined using computed tomography. The true values were compared with the values derived by the 45º oblique method after correcting the distortion using a formula. results. With the true values based on computed tomography as references, the neck shaft angle and anteversion of the 3 subjects deviated +0.82º to +4.66º and -2.14º to +2.55º in lateral 45º oblique radiographs, respectively, whereas the corresponding values in medial 45º oblique radiographs were +0.98º to +5.93º and -10.09º to +1.58º. The lateral 45º oblique method resulted in smaller range of deviation and were more accurate. conclusion. This 45º oblique method is useful in surgical planning, especially for femoral derotational A 45-degree radiographic method for measuring the neck shaft angle and anteversion of the femur: a pilot study

Validity and reliability of different techniques of neck–shaft angle measurement

“…The neckeshaft angle (NSA), also known as the caputecollumediaphyseal angle, is the angle formed by the intersection of a line passing through the femoral shaft and a line passing through the femoral head and neck. It is an important parameter to assess the geometry of the proximal femur, 1 as well as pathologies in adult and paediatric patients, such as hip dysplasia, 2 osteoarthritis, 3 and the risk of femoral neck fracture. 3,4 NSA is also related to other hip parameters, including femoral head offset, femoral neck length, 5 and acetabular version, 6 and is commonly used in pre-surgical planning of the proximal femur.…”

Measuring femoral neck torsion angle using femoral neck oblique axial computed tomography reconstruction

“…Methods for measuring femoral anteversion include biplanar [4,5], Dunn axial roentgenography [6], 45-degree radiographic method [3], sinus wave method [7], ultrasound [8], magnetic resonance imaging (MRI) [9], and computed tomography (CT) [1]. It is widely agreed that CT provides the most accurate measurement of femoral torsion angle [10], but any evaluation of the FNTA depends on the accurate determination of the location of the femoral neck axis.…”

“…FNTA is commonly measured when studying development dysplasia of the hip [2], LeggCalvé-Perthes disease, slipped capital femoral epiphysis, risk of osteoarthritis, femoral neck fracture, hip instability, and cerebral palsy. It is also used for diagnosing pediatric in-toeing or out-toeing gait as well as for surgical planning for derotation osteotomy of the femur and total hip replacement [3]. Accurate measurement of the angle is critical when surgical treatment is contemplated.…”

Using the Axial Oblique View of Computed Tomography (CT) in Evaluating Femoral Anteversion: A Comparative Cadaveric Study

“…By tradition, femoral anteversion measurement depends on the information obtained from a detailed physical examination using rotational profiles, including a trochanteric prominence angle test [ 2 ] and biplane radiography with specialized patient positioning or technique [ 5 ]. For this, computed tomography (CT) scans have become the most common imaging modality and the gold standard for clinical assessment due to their high accuracy and reliability [ 6 , 7 ].…”