Warning: include_once(../article_type.php): failed to open stream: No such file or directory in /home/suxhorbncfos/public_html/oroaj/OROAJ.MS.ID.555954.php on line 202
Warning: include_once(): Failed opening '../article_type.php' for inclusion (include_path='.:/opt/alt/php56/usr/share/pear:/opt/alt/php56/usr/share/php') in /home/suxhorbncfos/public_html/oroaj/OROAJ.MS.ID.555954.php on line 202
*Corresponding author: Ahmed Zaghloul, Department of Orthopaedic Surgery, Faculty of Medicine, Mansoura University, Egypt
How to cite this article: Ahmed Zaghloul, Elalfy M M, Medhat Tawfik M, Gamal El-Adl El-S, Akram H. Computing Measurements of Femoral Neck Shaft Angle in Children and Adolescents from Nile Delta. Ortho & Rheum Open Access J. 2020; 17(1): 55595410.19080/OROAJ.2020.17.555954
Background: Despite ongoing anthropological and orthopaedic interest in the ranges and patterns of variation of the femoral neck shaft angle (NSA) under varying normal and abnormal conditions, there has been little consideration of normal ranges of variation of this trait in Egyptian populations.
Purpose: This study was designed to evaluate the normal values of femoral NSA in Egyptian children and adolescents and factors which may affect this angle.
Study type: A Cross Sectional Descriptive study.
Methods: This study included 200 hips in 100 normal children and adolescents from the attendants of Orthopaedic Outpatient Clinics, in our institution. All individuals were subjected to a comprehensive orthopaedic examination to exclude those with orthopaedic problems affecting lower limbs or are likely to affect lower limbs e.g. spine and pelvis. Computed Tomography (CT) was used in measurement of femoral NSA through an Antero-Posterior Scanogram of pelvis and thigh.
Results: This study included 49 males and 51 females with mean age of 9.78±3.06 years. The mean body weight of the subjects was 34.78±14.16 Kg, the mean height 132.09±17.59 cm and the mean Body Mass index (BMI) was 19.14±3.92. The NSA ranged from 116o to 148o with mean angle of 133.23o ± 5.30 regardless the side. The means of NSA of the right and left sides were nearly equal with significant differences were found when right and left sides were compared in every subject. There were negative correlations between age, weight, height, BMI and NSA with no significant sex-specific differences reported.
Conclusion: There are many factors which may influence NSA size, for example: studied population, age, weight, height, side, and BMI.
According to the literature, there has been little consideration of normal ranges and variations of this trait in Egyptian populations, especially in Children and adolescents. This study may help to determine normal values of femoral NSA in Egyptian children and adolescents and factors which may affect this angle e.g. age, sex, side, weight, height, and BMI. Hence, we can make the best benefit of radiological studies and reach maximum efficacy in dealing with hip disorders which may correlate with variations of femoral NSA in this age group.
The proper action of hip joint depends on the congruence of articular surfaces of the head of the femur and the acetabulum .
So, morphology of the proximal femur, especially, the relationships among the head, neck, and proximal shaft, has been a subject of interest and debate in orthopaedic literature dating back to at least the middle of 19th century. As an area susceptible to numerous paediatric and adult disorders, many of which may correlate with variations in this morphology or whose treatment might benefit from a detailed understanding of this area’s anatomy .
The femoral head comprises 2/3 of a sphere. It is attached to the femoral metaphysis via the neck . The femoral neck is well developed in humans, with global orientation slanting upwards and forwards . The direction of the femoral neck is characterized by two factors: inclination and anteversion . The femoral neck inclination or femoral neck-shaft angle (NSA) is the angle between the longitudinal axes of the femoral neck and the
shaft and it is also called Caput- Collum - Diaphyseal angle (CCD
angle) . In normal hips NSA should cause the longitudinal axes
of the femoral necks to cross at the point of body weight . Also,
the importance of this feature is that the femoral shaft is laterally
displaced from the pelvis, thus facilitating for joint motion .
Several factors are quoted which influence NSA size in postnatal
life: epiphyseal cartilage activity, perfusion of femoral
epiphysis, muscle action, hormones, static factors, body weight
and finally disease. The most spectacular is the influence of
age during human growth from childhood to adulthood the
NSA decreases significantly. This is a result of changes in body
proportions followed by adaptation of the hip joint to vertical
posture and gait in changed conditions . This angle normally
measures approximately 150o in new-borns and 126o in adults
(Coxa Norma) . Any deviation appearing during development
which exceeds the normal values of the NSA may cause a number
of disturbances , which may be associated with problems in
the loading of the hip joint, that may result in non-economic gait
and premature wear of the joint . An abnormally small angle is
known as Coxa Vara and an abnormally large angle as Coxa Valga
The clinical importance of neck shaft angle of femur lies in
the diagnosis, treatment, and follow-up of fractures of the femoral
neck, trochanteric fractures, slipped upper femoral epiphysis,
developmental dysplasia of the hip and neuromuscular disorders
of the lower extremity. On the other hand, the effectiveness
of management of such disturbances is often assessed by
radiological studies. But the value of radiological studies has been
limited because of lack of available data to establish the limits of
normal measurements of this angle. From all the above, the need
to know the normal measurements of the femoral NSA becomes
very important to make the best benefit of radiological studies
and reach maximum efficacy in dealing with those disturbances.
This study is going to measure femoral NSA and to detect factors
that may affect this angle as age, sex, body weight, height, and
body mass index (BMI) in Egyptian children and adolescents from
A Cross Sectional Descriptive study included 200 hips in
100 normal children and adolescents from the attendants of
Orthopaedic Outpatient Clinics in our institution.
Subjects were selected to represent boys and girls in
the age group between 5 years and 15 years, till fulfillment of the
A. Inclusion criteria
Children and adolescents with orthopaedic problems not
affecting the lower limbs were included.
B. Exclusion criteria
Children and adolescents with orthopaedic problems affecting
lower limbs or are likely to affect lower limbs e.g. spine or pelvis,
The ethical committee in our institution has accepted the
performance of this study. Parents’ consent was mandatory for
inclusion of every child or adolescent in the study after detailed
explanation of the procedure and its aim and drawbacks.
Subject Communication and Preparation
Demographic data regarding name, age, sex, weight, and
height were collected with complete explanation of the procedure
to alleviate fears and ensure a successful procedure.
Computed Tomography (CT) was used in determination and
measurement of femoral neck shaft angle through an Antero-
Posterior Scanogram of pelvis and thigh.
A. Subject position
Supine, feet-first position with his or her arms placed at sides
or across upper chest. Then, align mid sagittal plane of the subject
to center line of CT table (couch) (Figure 1).
B. Part position
Ensure that the pelvis is not rotated; distance from table
top to each ASIS should be equal. Then, separate, and internally
rotate the entire leg 15o to 20o to compensate for femoral neck
anteversion and in situ external rotation of the subject (Figure 2).
C. Radiation dose
As for all imaging procedures, adherence to the ALARA
principle was required to reduce dose to subjects and personnel.
Anyone who must remain in the CT exam room during the
procedure wearied protective lead apparel. Subject led shielding
of radiosensitive organs obscure pelvis anatomy and was not used.
The NSA is the angle formed by the intersection of the femoral
neck and shaft axes (Figure 3).
A. Computing the shaft Axis
Horizontal lines in three sequential points 1 Cm apart at the
isthmus were drawn from one side of the shaft to the opposite
side, and then the mid points of these lines were connected to
from the shaft axis.
B. Computing the Neck Axis
The axis of the neck was drawn from the center of the head of
the femur towards midpoint of the base of the neck.
Data were analysed by SPSS software version 24. Qualitative
data were expressed as number and percentage within group.
Quantitative data were tested for normality using Kolmogorov
Smirnov test and they were expressed as mean + standard
deviation or median and range. Comparison between the
quantitative data of three study groups was carried out by oneway
ANOVA test. Qualitative data were compared between the
three groups using Chi square test. P value < 0.05 was considered
significant in all used tests.
The age of the subjects included in this study ranged from 5
to 15 years old, with mean age of 9.78±3.06 years; 49 were males
(49.0%) and 51 were females (51.0%). The body weight of the
involved individuals ranged from 17 to 79 Kg, with a mean of
34.78±14.16 Kg. The height varied from 93 to 171.5 cm with mean
height of 132.09±17.59 cm. The Body Mass index (BMI) was 12.5
to 35.1 with mean BMI of 19.14±3.92.
B. Neck Shaft Angle
The neck shaft angle in the obtained sample ranged from 116o
to 148o with mean angle of 133.23o ± 5.30 regardless the side,
and from 116o to 148o with mean angle of 133.04o ± 5.36 at right
side, while it was 116o to146o with mean angle of 133.42o ± 5.27
at left side (Table 1).
C. Relation between side and NSA
The means of neck shaft angle of the right and left sides were
nearly equal. Although, significant differences were found when
right and left sides were compared in every subject (using Paired
t-test) reaching 1.08o ± 1.05 and ranging from 0.5o to 4o (Table
D. Relation between age and NSA
It was found that there was a statistically significant decrease
in NSA with increasing age (Table 3).
E. Relation between sex and NSA
The difference in the NSA between males and females was
found to be statistically insignificant (Table 4).
F. Relation between weight and NSA
The difference in NSA was inversely related to change in
weight and was found to be statistically significant. The angle
decreased with increasing weight (Table 5).
G. Relation between height and NSA
There was a statistically insignificant decrease in NSA with
increasing height (Table 6).
H. Relation between Body Mass Index (BMI) and NSA
The difference in NSA was inversely related to change in BMI
and was found to be statistically highly significant. The angle
decreased with increasing BMI (Table 7).
There has been ongoing interest in degrees and patterns of
variation of the medial inclination of the femoral head and neck
relative to its diaphysis at least since [7,8], with the extreme
vertical and horizontal positions characterized as coxa valga
and coxa vara. This orientation is most effectively evaluated
through its quantification by the femoral NSA (collodiaphyseal,
cervicodiaphyseal angle, or angle of inclination) . Despite
ongoing anthropological [10-12] and especially orthopaedic [13-
22] interest in the ranges and patterns of variation of the femoral
NSA under varying normal and abnormal conditions, there has
been little consideration of normal ranges and variations of this
trait in Egyptian populations.
Previous studies investigating the morphometry of the hip
and proximal femur varied in the technique used and populations
studied. Most authors agree that there is considerable individual
variation and wide standard deviation in NSA. Some studies
have used measurements obtained directly from the dry bones
[16,23-26] or radiographic examination of dry femurs [2,27,
28,29], whereas others have used radiological studies of subjects
e.g. radiographs [30-35], computed tomography (CT)  and
DXA-based measurements [37-39]. In this work we measured
NSA using CT Scanogram in Egyptian children & adolescents in
the age group between 5 and 15 years old. As, several studies
[7,8,11,18,21] have shown that the NSA is very stable from
midadolescence through most of adulthood.
Asymmetry and Femoral NSA
Asymmetry in the human lower limb is frequently assumed
to be low and random with respect to side, although some
authors [11,40-42] have noted variably greater degrees of left leg
robusticity in individual samples. If greater left leg robusticity is
the dominant pattern, this should be reflected in lower neck shaft
angles on the left side. Anderson and Trinkaus in their survey of
femoral neck shaft angles in modern, historic, and prehistoric
population samples reported that even though individual bilateral
asymmetry existed in the NSA and some samples exhibited sexual
dimorphism, there were no consistent patterns of asymmetry
In the present study, there was no significant difference in
the means of NSA of the right and left sides. However significant
differences were found when right and left sides were compared
in every subject (using Paired t-test) and we found that left side
is equal to right side in 37 subjects, left is smaller than the right
in 21 subjects with difference ranging from 1o to 3o and left is
larger than the right in 42 subjects with difference ranging from
0.5o to 4o .So, Asymmetry of the proximal femur especially NSA
is assumed to be random with respect to side , showing a natural
tendency to bilaterality.
Age and Femoral NSA
There are several factors quoted which influence NSA size
in postnatal life: epiphyseal cartilage activity, perfusion of the
femoral epiphysis, muscle action, hormones, static factors, body
weight and, finally, disease. The most spectacular is the influence
of age. During human growth from childhood to adulthood the
CCD angle decreases significantly. This is a result of changes in
body proportions followed by adaptation of the hip joint to vertical
posture and gait in changed conditions [44,45]. The classical
literature describes the angle of the femur axis or inclination
angle as being of about 150o in infants; 140o in youngsters; 125o
in adults; and 120o in the elderly .
Bulandra and his colleagues in their research performed on
106 human foetuses, 62 of which were male and 44 female in age
from 16 to 38 weeks suggested that the process of adaptation to
vertical posture and bipedal gait starts during pregnancy and is
manifest as an inborn feature . In the present study, we confirm
the effect of age on the femoral NSA. As, we found a significant
decrease in this angle with increase in age.
Gender and Femoral NSA
When searching for sexual differences in the NSA, some
authors reported larger values of NSA in males than in females in
adult age group [16,30]. In contrast, other authors documented
no difference between both sexes [2,33]. In the current study, no
significant sex-specific differences were found in the NSA.
Biomechanical loading and Femoral NSA
Since Humphry , it has been noted that there is a general
inverse relationship between biomechanical loading levels at the
hip and the NSA. The normal process of reduction in the angle to a
more varus orientation of the femoral neck during development is
dependent on the assumption of normal weight-bearing through
the hip region and increasing locomotor activity levels during
development [17,18, 21,46-48].
This is particularly evident in cases of reduced or absent
weight-bearing during development. This is seen in infantile
congenital dislocated hip [46-48], slipped femoral capital
epiphysis , cerebral palsy [18,21] and immature idiopathic
scoliosis . In these cases of minimal weight-bearing, the
femoral neck remains in a coxa valga position. Surgical correction
of the condition with consequent normal weight-bearing produces
‘a gradual decreasing of the NSA of the femur’ over a period of a
maximum of 2 years .
In addition, Houston and Zaleski demonstrated that, in
immature individuals, the degree of decrease in femoral NSA
during development is correlated with the level of normal physical
activity. The higher the activity level, the greater the decrease in
NSA from the neonatal value as the individual matures . In the
present study, we assessed the effect of body weight, height and
BMI on the femoral NSA. We noticed that there was non-significant
decrease in NSA with increase in height but, there was significant
decrease in angle with increase in weight and BMI which may
confirm the inverse relationship between biomechanical loading
levels at the hip and the NSA. These considerations thus indicate
that the femoral NSA is heavily influenced by load levels in the
hip region during development. Eventually, further analyses and
refinements in methodology used and population studied may
be expected to clarify these findings and address some of the
unresolved questions that surround the NSA, which may shed light
on hitherto unexplored aspects of the proximal femoral geometry.
There are many factors which may influence NSA size, for
example: studied population, age, weight, height, side, and BMI.
Such findings may highlight the degree of variability likely to be
encountered in this orthopaedically relevant region and challenge
surgeons to be mindful of the impact that individual anatomic
variation might have on outcomes for procedures not taking this
variability into consideration.
Hefti F (2007) Pelvis, hips and thighs: Biomechanics of the hip. In: Pediatric Orthopaedics in Practice Springer-Verlag Berlin Heidelberg; New York, USA, pp. 169-176.
Schuenke M, Schutle E, Schumacher U (2006) Lower Limb: Bones, ligaments, and joints. In: Thieme Atlas of Anatomy: General Anatomy and Musculoskeletal System, 1stedition, edited by Ross L and Lamperti E Georg Thieme Verlag, Stuttgart, New York, USA, pp. 360-418.
Charpy A (1885) Le col du fé Bulletin de la Société d' Anthropologie de Lyon 3: 282-300.