Keywords anthropometry - arthroplasty - hip joint - tomography, x-ray computed
Introduction
Knowledge on hip anthropometry, that is, the average anatomical measurements from
a given population, is critical. It is known that bone structures dimensions and shape
may vary according to age, gender, and ethnicity, among other factors.[1 ]
The mastery of these measures increases diagnostic accuracy and improves the treatment
of conditions such as femoroacetabular impingement (FAI). In addition, anthropometry
aids the development of implants for femoral fractures management.[2 ] This knowledge is also critical to total hip arthroplasty (THA), in which implants
should be properly dimensioned to accommodate individual anatomical variabilities
as accurately as possible; otherwise, complications resulting from dimensional incompatibility
between implants and recipient bones can lead to early failure due to inadequate load
transfer.[2 ]
[3 ]
[4 ]
[5 ]
Due to the lack of complete anthropometric studies on the Brazilian hip, we investigated
the average hip joint anatomy of a regional population of the state of Paraná, using
hip measurements obtained during abdominal computed tomography scans, and compared
them with literature data from other populations. We also analyzed whether gender
or age would have a significant correlation with measures range.
Material and Methods
Retrospective study based on anthropometric data obtained from 200 computed axial
tomography (CAT) scans from patients visiting the imaging center of a tertiary hospital
in Paraná, Brazil, from October 2014 to August 2018.
Abdominal CAT scans with axial and coronal planes reconstruction (i.e., sections from
the acetabular roof, cranially, up to 2 cm below the base of the lesser trochanter,
caudally) were included at random for anthropometric measurements determinations.
Scans presenting hip fractures, hardware, or another condition that could result in
distorted measurements, such as bone tumors or congenital deformities, were excluded.
The study project was duly registered at Plataforma Brasil and approved by the institutional
Ethics Committee (CAAE) under number 96182818.5.0000.5226.
Digitized images were obtained using a 16-channel Philips Model MX16EVO2 equipment
(Philips, Amsterdam, Netherlands) and stored in an Aurora Picture Archiving and Communication
System (PACS system, Pixeon, São Caetano do Sul, SP, Brazil). All evaluations and
measurements were performed using the Arya software, from the same developer. The
right hip was chosen for all measurements, which were made by the first coauthor.
The data were statistically treated and compared with those of similar studies. [Figures 1 ], [2 ], and [3 ] show illustrative diagrams of the measurements.
Fig. 1 Illustration of femoral measurements.
Fig. 2 Illustration of acetabular measurements.
Fig. 3 Illustration of combined measurements.
The following parameters were evaluated in coronal sections :
Sharp angle (acetabular index): angle between a standard horizontal (bi-ischial) line and another line connecting
the inferior-medial end to the superolateral acetabular end in its largest diameter.[6 ]
[7 ]
[8 ]
Tönnis angle: angle between a standard horizontal line and another line drawn from the most medial
point to the most lateral point of the sourcil.[1 ]
[8 ]
[9 ]
[10 ]
Acetabular depth: orthogonal distance from the midpoint of the longest line connecting the inferior-medial
and superolateral acetabular ends to the bottom of the acetabulum in its largest diameter.[8 ]
[11 ]
Wiberg (lateral center-edge) angle : angle between a line drawn vertically through the center of the femoral head and
another line drawn from the center of the femoral head to the most lateral edge of
the sourcil.[12 ]
[13 ]
Medial center-edge: angle between a vertical line drawn through the center of the femoral head and another
line connecting the center of the femoral head to the most medial edge of the sourcil.[9 ]
[14 ]
[15 ]
Acetabular arc: sum of the lateral center-edge and medial center-edge angles.[16 ]
[17 ]
Delta (Notzli) angle: angle between a line drawn from the center of the femoral head to the most medial
part of the sourcil and another line drawn from the center of the head to the most
lateral part of the femoral head fovea at the tomographic section in which its location
is deeper.[18 ]
Head extrusion index: this index is measured at the largest diameter of the femoral head. It is determined
using vertical, orthogonal lines to a standard horizontal line, drawn from the most
lateral edge of the sourcil to the most lateral edge of the femoral head. The index
is obtained by dividing the horizontal measurement of the extruded part by the cephalic
diameter.[16 ]
Cervical-diaphyseal angle: angle between the anatomical axis of the femur (traced using points at the center
of the medial-lateral diameter of the diaphysis in two distinct regions) and the axis
of the neck (traced from a central point of the craniocaudal diameter of the femoral
neck to the rotation center of the head).[1 ]
[2 ]
[7 ]
Lateral offset: orthogonal distance from the femoral head rotation center to the anatomical axis
of the femur.[11 ]
[12 ]
Vertical offset: orthogonal distance from the center of the femoral head to a line touching the most
cranial end of the greater trochanter.[12 ]
Femoral neck diameter: endosteal diameter orthogonal to the neck axis at its largest diameter section.[10 ]
Femoral canal diameter: medium-lateral endosteal diameter of the femoral canal. It is measured at 5 points,
namely: 2 cm above the cranial edge of the lesser trochanter, at the level of the
cranial edge of the lesser trochanter, at the level of the lesser trochanter apex,
at the level of the caudal edge of the lesser trochanter, and 2 cm distal to the caudal
edge of the lesser trochanter.[2 ]
The following parameters were evaluated in axial sections :
Acetabular version: angle between the ends of the anterior and posterior acetabular walls and an orthogonal
line to another standard line that connects the posterior pelvic margins at the level
of the largest diameter of the head.[13 ]
[14 ]
Anterior acetabular sector angle (AASA): angle between a line passing through the centers of the heads (in their largest diameters)
and another line from the center of the head to the end of the anterior wall.[15 ]
Posterior acetabular sector angle (PASA): angle between a line passing through the centers of the heads (in their largest diameter)
and another line drawn from the center of the head to the end of the posterior wall.[15 ]
Horizontal acetabular sector angle (HASA): AASA plus PASA.[15 ]
Femoral head diameter: largest diameter of the femoral head.[10 ]
Acetabular diameter: from the section with the largest head diameter.[10 ]
Head-neck offset:
[10 ] three parallel lines are drawn: 1) axis of the femoral neck. 2) a line parallel
to the first one, which touches the anterior cortex of the cervix. 3) a line parallel
to the other two, which touches the anterior cortex of the femoral head. The offset
is given by the distance between lines 2 and 3.
Anterior alpha angle: an angle between the axis of the femoral neck and a line connecting the femoral head
rotation center to its point of sphericity loss.[16 ]
[19 ]
Femoral canal diameter: anteroposterior diameter of the femoral canal. It is measured at 5 points: 2 cm above
the lesser trochanter, at the level of the upper border of the lesser trochanter,
at the apex of the lesser trochanter, at the lower edge of the lesser trochanter and
2 cm distal to the lesser trochanter.[2 ]
Data was submitted to the Kolmogorov-Smirnov test to determine the normal distribution
of anthropometric values. The Bartlett test was used to ascertain whether K variances
in groups (anthropometric measurement types) were homogeneous. The chi-squared test
for categorical variables was performed to identify trends in age and gender, whereas
the analysis of variance (ANOVA) test compared means (considering a p -value < 0.05 as significant).
Results
This study analyzed CAT data from 200 patients. In each case, 30 measurements were
collected, totaling 6,000 data for statistical analysis.
[Table 1 ] shows the demographic data of the studied population. The mean age of the patients
was 49 years old (µ = 48.90), with a standard deviation of ± 20 years (σ = ± 20.25).
The average (self-reported) ethnic composition of the population from this hospital
unit was provided by inpatient system, and it is composed as follows: 69.2% white,
4.4% black, and 26.4% brown subjects.
Table 1
Characterization
n
%
Age range
≥ 50 years old
96
48%
< 50 years old
104
52%
Gender
Female
86
43%
Male
114
57%
[Table 2 ] describes mean, standard deviation, minimum, and maximum values from the general
sample. Mean values were usually deemed normal.
Table 2
Radiological measurement
Mean
Standard deviation
Minimum value
Maximum value
Sharp angle (degrees)
40.3
4.8
27.0
63.0
Tönnis angle (degrees)
3.4
6.8
−13.0
50.0
Depth (mm)
19.0
2.9
11.0
30.0
Lateral center-edge angle (degrees)
33.8
8.3
15.0
64.0
Medial center-edge angle (degrees)
33.4
8.6
13.0
66.0
Acetabular arc (degrees)
66.9
11.2
38.0
103.0
Delta angle (degrees)
27.8
8.8
5.0
52.0
Extrusion index (%)
14.0
9.8
0.0
52.0
Cervical-diaphyseal angle (degrees)
129.4
5.8
116.0
145.0
Lateral offset (mm)
37.6
3.4
28.0
45.0
Vertical offset (mm)
−1.3
8.8
−16.0
27.0
Neck diameter (mm)
25.2
4.0
17.0
37.0
Acetabular version (degrees)
21.2
6.5
7.0
47.0
AASA (degrees)
63.3
9.7
26.0
92.0
PASA (degrees)
105.9
14.0
71.0
159.0
HASA (degrees)
169.4
19.5
129.0
252.0
Cephalic diameter (mm)
41.8
4.0
32.0
52.0
Acetabular diameter (mm)
52.4
4.0
41.0
61.0
Head-neck diameter (mm)
9.4
2.7
4.0
28.0
Anterior alpha angle (degrees)
47.9
7.2
30.0
71.0
AP: + 2 cm (mm)
34.9
6.0
20.0
55.0
ML: + 2 cm (mm)
40.6
6.3
22.0
62.0
AP: superior (mm)
31.0
4.8
20.0
45.0
ML: superior (mm)
36.8
4.4
24.0
50.0
AP: apex (mm)
27.4
5.0
17.0
40.0
ML: apex (mm)
37.6
5.9
16.0
51.0
AP: inferior (mm)
22.6
4.0
12.0
35.0
ML: inferior (mm)
24.4
5.0
15.0
42.0
AP: - 2 cm (mm)
17.8
3.3
10.0
28.0
ML: - 2 cm (mm)
18.0
3.4
11.0
38.0
A lateral or anterior center-edge angle lower than 20°, suggesting hip developmental
dysplasia, was found in 12 hips, resulting in a prevalence rate of 6%. Twenty-two
hips, or 11% of the sample, presented alpha angles above 55°, suggesting cam-type
femoroacetabular impingement (FAI). Twenty-three hips, or 11.5%, presented negative
Tönnis angles, suggesting pincer-type FAI; in addition, 3.5% of this sample had findings
suggesting mixed-type FAI. Thus, 26% of the sample had some sign suggestive of FAI.
[Table 3 ] shows measurements by age group (< 50 or ≥ 50 years old). Measurements with statistically
significant differences (p < 0.05) are in bold. Some anthropometric measurements were found to be significantly
different depending on the age group.
Table 3
Variable
Age
(years old)
Mean
Standard deviation
Minimum value
Maximum value
P -value
Coronal Section
Sharp angle (degrees)
≥ 50
39.1
5.5
27.0
63.0
0.000*
< 50
41.5
3.8
28.0
49.0
Tönnis angle (degrees)
≥ 50
3.4
6.8
−12.0
50.0
0.977
< 50
3.4
6.8
−13.0
35.0
Depth (mm)
≥ 50
18.7
2.8
12.0
28.0
0.187
< 50
19.3
3.1
11.0
30.0
Lateral center-edge angle (degrees)
≥ 50
35.9
8.1
22.0
62.0
0.001*
< 50
31.9
8.0
15.0
64.0
Medial center-edge angle (degrees)
≥ 50
32.6
7.1
13.0
50.0
0.188
< 50
34.2
9.7
19.0
66.0
Acetabular arc (degrees)
≥ 50
68.6
10.7
47.0
103.0
0.041*
< 50
65.4
11.4
38.0
103.0
Delta angle (degrees)
≥ 50
28.3
8.8
5.0
52.0
0.409
< 50
27.3
8.8
5.0
42.0
Extrusion index (%)
≥ 50
11.2
8.6
0.0
34.0
0.000*
< 50
16.7
10.2
0.0
52.0
Cervical-diaphyseal angle (degrees)
≥ 50
128.5
5.8
116.0
142.0
0.036*
< 50
130.2
5.8
116.0
145.0
Lateral offset (mm)
≥ 50
37.6
3.3
29.0
44.0
0.799
< 50
37.5
3.5
28.0
45.0
Vertical offset (mm)
≥ 50
−2.8
8.1
−15.0
24.0
0.028*
< 50
0.0
9.2
−16.0
27.0
Neck diameter (mm)
≥ 50
25.2
3.7
18.0
37.0
0.947
< 50
25.2
4.2
17.0
37.0
Axial section
Acetabular anteversion (degrees)
≥ 50
22.6
6.5
7.0
44.0
0.003*
< 50
19.9
6.3
8.0
47.0
AASA (degrees)
≥ 50
65.4
10.5
35.0
87.0
0.002*
< 50
61.3
8.6
26.0
92.0
PASA (degrees)
≥ 50
110.4
14.8
80.0
159.0
0.000*
< 50
101.6
11.7
71.0
159.0
HASA (degrees)
≥ 50
176.0
20.9
132.0
234.0
0.000*
< 50
163.2
15.8
129.0
252.0
Cephalic diameter (mm)
≥ 50
41.5
3.7
32.0
50.0
0.337
< 50
42.1
4.2
33.0
52.0
Acetabular diameter (mm)
≥ 50
52.3
4.2
41.0
60.0
0.616
< 50
52.6
3.9
42.0
61.0
Head-neck offset (mm)
≥ 50
9.2
3.0
4.0
28.0
0.403
< 50
9.5
2.5
5.0
21.0
Anterior alpha angle (degrees)
≥ 50
48.2
7.6
30.0
71.0
0.526
< 50
47.6
6.7
30.0
67.0
In patients over 50 years old, the Sharp angle was greater, with a mean value of 41.5°;
and the mean lateral center-edge angle (µ = 35.9°) was also increased. Similarly,
the acetabular arc was greater (µ = 68.6°). Measurements from the axial sections revealed
that mean the acetabular version (µ = 22.6°), AASA (µ = 65.4°), PASA (µ = 110.4°),
and HASA (µ = 176°) were significantly higher in the older patient group.
In youngest patients, the mean extrusion index (µ = 16.7%) and the cervical-diaphyseal
angle were higher (µ = 130.2°).
Findings per gender
[Table 4 ] shows measurements in both genders. Values with statistically significant differences
(p < 0.05) are in bold. Some measurements were found to be significantly different comparing
males and females.
Table 4
Variable
Gender
Mean
Standard deviation
Minimum value
Maximum value
P -value
Coronal section
Sharp angle (degrees)
Female
40.5
5.4
28.0
63.0
0.636
Male
40.2
4.3
27.0
49.0
Tönnis angle (degrees)
Female
2.7
6.8
−13.0
35.0
0.223
Male
3.9
6.9
−11.0
50.0
Depth (mm)
Female
18.3
2.7
12.0
25.0
0.004*
Male
19.5
3.1
11.0
30.0
Lateral center-edge angle (degrees)
Female
35.5
9.5
16.0
64.0
0.013*
Male
32.6
7.1
15.0
54.0
Medial center-edge angle (degrees)
Female
33.7
8.1
17.0
62.0
0.650
Male
33.2
8.9
13.0
66.0
Acetabular arc (degrees)
Female
68.7
12.2
47.0
103.0
0.046*
Male
65.5
10.2
38.0
103.0
Delta angle (degrees)
Female
28.4
9.2
5.0
52.0
0.372
Male
27.3
8.5
5.0
47.0
Extrusion index (%)
Female
11.4
9.6
0.0
52.0
0.001*
Male
16.0
9.6
0.0
50.0
Cervical-diaphyseal angle (degrees)
Female
129.0
6.3
116.0
142.0
0.390
Male
129.7
5.5
116.0
145.0
Lateral offset (mm)
Female
36.5
3.6
28.0
45.0
0.000*
Male
38.3
3.1
30.0
45.0
Vertical offset (mm)
Female
−2.1
7.8
−15.0
15.0
0.265
Male
−0.7
9.4
−16.0
27.0
Neck diameter (mm)
Female
23.7
3.6
17.0
32.0
0.000*
Male
26.4
3.8
17.0
37.0
Axial section
Acetabular version (degrees)
Female
22.5
6.8
7.0
44.0
0.012*
Male
20.2
6.1
8.0
47.0
AASA (degrees)
Female
63.6
9.6
35.0
86.0
0.742ns
Male
63.1
9.8
26.0
92.0
PASA (degrees)
Female
107.8
13.6
73.0
159.0
0.086ns
Male
104.4
14.1
71.0
159.0
HASA (degrees)
Female
171.8
19.0
129.0
234.0
0.125ns
Male
167.5
19.7
129.0
252.0
Cephalic diameter (mm)
Female
39.4
3.2
32.0
50.0
0.000*
Male
43.6
3.5
36.0
52.0
Acetabular diameter (mm)
Female
50.0
4.0
41.0
60.0
0.000*
Male
54.2
3.0
45.0
61.0
Head-neck diameter (mm)
Female
8.9
2.3
4.0
14.0
0.055ns
Male
9.7
3.0
4.0
28.0
Anterior alpha angle (degrees)
Female
47.6
7.4
30.0
71.0
0.593ns
Male
48.1
6.9
30.0
65.0
Females presented significantly higher mean acetabular version angle (µ = 22.5°),
lateral center-edge angle (µ = 35.5°), and acetabular arc (µ = 68.7°).
Males presented higher mean extrusion index (µ = 16%), lateral offset (µ = 38.3 mm),
depth (µ = 19.5 mm), neck diameter (µ = 26.4 mm), head diameter (µ = 43.6 mm), and
acetabular diameter (µ = 54.2 mm).
[Table 5 ] shows that males presented significantly higher canal diameter compared to females.
[Table 6 ] reveals that there was no significant difference in femoral canal measurements when
comparing both age groups.
Table 5
Variable
Gender
Mean
Standard deviation
Minimum value
Maximum value
P -value
AP: + 2 cm
Female
33.1
5.5
22.0
52.0
0.000*
Male
36.2
6.1
20.0
55.0
ML: + 2 cm
Female
40.8
6.2
29.0
62.0
0.747
Male
40.5
6.3
22.0
60.0
AP: superior
Female
29.3
4.8
20.0
45.0
0.000*
Male
32.3
4.4
22.0
44.0
ML: superior
Female
35.6
4.2
24.0
50.0
0.001*
Male
37.7
4.4
25.0
49.0
AP: apex
Female
26.4
4.8
17.0
40.0
0.014*
Male
28.1
5.0
18.0
40.0
ML: apex
Female
36.3
5.1
19.0
50.0
0.008*
Male
38.6
6.3
16.0
51.0
AP: inferior
Female
22.2
4.2
14.0
32.0
0.147
Male
23.0
3.8
12.0
35.0
ML: inferior
Female
24.2
5.3
15.0
42.0
0.658
Male
24.5
4.8
15.0
41.0
AP: - 2 cm
Female
17.6
3.3
11.0
28.0
0.595
Male
17.9
3.3
10.0
28.0
ML: - 2 cm
Female
17.8
2.9
11.0
25.0
0.461
Male
18.2
3.7
12.0
38.0
Table 6
Variable
Age
(years old)
Mean
Standard deviation
Minimum value
Maximum value
P -value
AP: + 2 cm (mm)
≥ 50
35.0
5.5
22.0
52.0
0.780
< 50
34.8
6.5
20.0
55.0
ML: + 2 cm (mm)
≥ 50
40.2
6.9
22.0
62.0
0.323
< 50
41.0
5.6
28.0
57.0
AP: superior (mm)
≥ 50
30.7
4.6
22.0
42.0
0.386
< 50
31.3
5.0
20.0
45.0
ML: superior (mm)
≥ 50
36.9
3.7
28.0
46.0
0.880
< 50
36.8
5.0
24.0
50.0
AP: apex (mm)
≥ 50
27.0
4.7
18.0
38.0
0.334
< 50
27.7
5.2
17.0
40.0
ML: apex (mm)
≥ 50
38.1
4.6
25.0
51.0
0.249
< 50
37.1
6.9
16.0
50.0
AP: inferior (mm)
≥ 50
22.5
3.8
12.0
35.0
0.725
< 50
22.7
4.2
14.0
35.0
ML: inferior (mm)
≥ 50
24.5
4.5
18.0
40.0
0.723
< 50
24.3
5.4
15.0
42.0
AP: − 2 cm (mm)
≥ 50
17.5
2.9
12.0
27.0
0.372
< 50
18.0
3.7
10.0
28.0
ML: − 2 cm (mm)
≥ 50
18.3
3.2
12.0
29.0
0.315
< 50
17.8
3.6
11.0
38.0
Discussion
The present study analyzed abdominal CAT scans containing segmentations at the hip
joint level, allowing the characterization of average anthropometric measurements.
Computed axial tomography studies of the abdomen were used to decrease the selection
bias since they were probably not requested due to orthopedic complaints (and this
study did not evaluate previous symptoms).
The modern concept of FAI was described by Ganz and subdivided into three types: pincer,
when it results from acetabular changes, such as deep thigh, or global or focal retroversion;
cam, when changes are at a femoral level, usually due to loss of the head-neck offset;
and mixed, which is the most common type.
When investigating the prevalence of FAI-predisposing bone abnormalities in asymptomatic
subjects, Kang et al.[6 ] noted that the acetabular version angle ranged from 5 to 29°, with an average value
of 18°; this value is below the one found by our study, in which the acetabular version
angle ranged from 7°to 47°, with an average of 21.2°. Other authors have evaluated
measures potentially suggesting FAI. A measure widely described in the literature
is the center-edge angle of Wiberg. In this same study,[6 ] these values ranged from 21 to 46°, with an average of 34°. In a case series evaluated
by Murtha et al.,[8 ] this angle varied from 8.5°to 32.3°, whereas we found values ranging from 15° to
64°, with an average of 33.8°.
Tannast et al.[16 ] classified acetabula according to this measurement in 4 groups, in which angles
lower than 22° indicated dysplastic hips, from 23 to 33° were normal hips, from 34
to 39° revealed overcovering hips, and higher than 40° showed severe overcovering.
In our sample, the prevalence of hip developmental dysplasia was 6%, whereas 26% of
the cases presented some sign suggestive of FAI. Regarding the high prevalence of
signs suggesting FAI in our sample, it is extremely important to emphasize that FAI
syndrome diagnosis is not contingent on imaging data alone. Since we did not collect
data about any symptom presented by these patients, this finding must be only considered
from a morphological point of view, not a pathological one.
In gender-related analysis, Lepaage-Saucier et al.[14 ] and Kang et al.[6 ] found higher mean center-edge angles in men compared to women. Curiously, only Mineta
et al.[10 ] observed no differences between genders. Our sample was consistent with the previous
literature, showing greater angles in females when compared to males (35.5° and 32.6°,
respectively). Kang et al. also described a mean alpha angle of 45.5°, consistent
with our study, which revealed a value of 47.9°.
The delta angle is described as a sign of dysplasia. In normal hips, Beltran et al.
reported mean values of 22.7°, with standard deviation (SD) values of 12.6°. In our
study, the mean delta angle was 27.8°, with a SD value of 8.8°. This finding is probably
related to the greater acetabular coverage in comparison to the aforementioned studies.
Lepaage-Saucier et al.[14 ] reported a mean Tönnis angle 6°, with no differences between genders. In contrast,
Mineta et al.[10 ] found lower values in men and elderly patients. In our sample, the Tönnis angle
showed no significant differences in both age groups.
Another research[1 ] revealed the following mean values: Sharp angle, 39.2° (smaller compared to our
result of 40.3°), lateral-center edge angle, 32.7 ° (smaller compared to our result
of 33.8°), cervical-diaphyseal angle, 139.5 ° (greater compared to our result of 129.4°),
acetabular version, 18.2° (inferior to our finding of 21.2°), acetabular depth, 25 mm
(much lower compared to our result of 19 mm).
Anda et al.[15 ] described the anterior and posterior sectorial arcs of the hip, reporting mean values
consistent with our study, with a difference of only 0.3° in AASA and 0.9° in PASA.
Our population presented lower mean acetabular and femoral head diameter, at 41.8
and 52.4 mm, respectively, compared to 45.3 and 52.6 mm according to Hauser et al.[20 ]
Lateral offset is a measure of direct interest for biomechanical reconstruction in
hip arthroplasty. Husmann et al. showed a mean lateral offset of 40.5 mm, while our
population presented an average value of 37.6 mm, with lateral offsets ranging from
28 to 45 mm.
The joint analysis of our results, specifically in the group over 50 years old, indicated
the acetabular deepening related to aging. This fact was demonstrated by the significantly
greater horizontal acetabular sectors angles, the center-edge angle, and the acetabular
arc, along with a lower extrusion index. In addition, a varusing was noted, with reduced
cervical-diaphyseal angle and vertical offset, the latter with a negative mean value
in this subsample.
Our data on endosteal femoral canal diameter allows us to outline the average shape
of the metaphyseal region, which would be critical to build a custom prosthetic implant.
Although the mean values from our study are consistent with those obtained by Noble
et al.,[17 ] our measurements presented higher variability compared to most previous studies.
In addition, there were differences regarding femoral neck diameter measurements.
Noble reported an average diameter of 16.5 mm, ranging from 10 to 22 mm, while we
found an average value of 25.2 mm and measurements ranging from 17 to 37 mm. We believe
that this difference may be due to the ethnic multitude found in Brazil. Such variability
has a direct impact on the design of cephalomedullary implants with anti-rotating
screws. The anatomical variety of our population would require a wide range of device
sizes.
The current study has limitations inherent to its retrospective design, and we have
not analyzed whether these subjects had any symptoms or what was the reason for the
imaging test. In addition, measurements performed by a single examiner may be susceptible
to variation even though CAT scans have shown good intra and interobserver confidence
in some analysis. As positive points of this research, we emphasize that it demonstrated,
in an unprecedented way, detailed anthropometric mean values of the hip joint from
a Brazilian population. We have also shown that there are variations in patients from
different age groups. Our protocol may be replicated promptly in multicenter studies,
which we deem necessary to cover a larger, more diversified sample from other regions
of Brazil.
Conclusions
The present study characterized in detail the anthropometry of the hip joint of a
regional Brazilian population. It also demonstrated significant morphological differences
of the hip between different age groups and genders.
