Basic concepts of femoral neck anteversi 001
1989, The British Journal of Radiology, 62, 114—116
Basic concepts of femoral neck anteversion: comparison of
two definitions
By *Arne Hoiseth, M D , tOlav Reikeras, M D and ttErik Fonstelien, MSc
Department of Diagnostic Radiology, tDepartment of Surgery, Orthopedic Section and ttDepartment of
Clinical Physiology, University of Oslo, Ulleval Hospital, 0407 Oslo 4, Norway
(Received June 1988 and in revised form October 1988)
Abstract. Femoral neck anteversion is determined by the neck, shaft and knee axes. It is commonly assumed that the neck axis is a
straight line connecting the centre of the femoral head, the centre of the femoral neck and the axis of the femoral shaft. However, the
line through the centre of the femoral head and neck crosses anterior to the axis of the femoral shaft. A distinction has therefore to
be made between two principal different definitions of anteversion, denoted ANTEV 1 and ANTEV 2 in this paper, depending on
the precise definition of the neck axis. Previous studies have indicated substantial differences between these definitions. The present
study, using precise measuring methods, shows that the definitions have a systematic but small spread of differences. The large
individual variation previously found between the two definitions is therefore caused mainly by the measuring methods and to a
lesser extent by real anatomical variations.
The femoral neck axis is traditionally considered to be a
straight line connecting the centre of the femoral head
and the centre of the femoral neck with the axis of the
femoral shaft (Dunn, 1952; Dunlap et al, 1953;
Magilligan, 1956; Weiner et al, 1978; Ruby et al, 1979).
However, the line from the centre of the femoral head to
the centre of the femoral neck, the head-neck axis,
usually passes in front of the axis of the femoral shaft
(Norman, 1969; Grote et al, 1980) and therefore differs in
principle from the definition using the line from the
centre of the femoral head to the intersection with the
shaft axis (head-shaft axis) (Fig. 1). Two different
definitions of anteversion can therefore be made,
depending on whether the head-neck or the head-shaft
axes are used.
In this work the first angle is denoted ANTEV 1 and
the latter ANTEV 2 in accordance with Henriksson
(1980). It has previously been shown that ANTEV 2 is
larger than ANTEV 1 (Grote et al, 1980; Henriksson,
1980; Herrlin & Ekelund, 1983; Reikeras et al, 1985b).
Previous studies have also shown a large spread of
differences (Henriksson, 1980; Reikeras et al, 1985b).
In both practical and theoretical contexts, it is
important to determine the anatomical and
biomechanical implications of the two angles. In this
context, it is the spread of the difference between the two
definitions that is most relevant. A systematic difference
can be dealt with by correcting the values and therefore
has few clinical or biomechanical implications. The
spread of the differences may, however, indicate
differences of importance. Such a spread of the measured
differences may, however, be due to poor precision of the
measuring methods rather than to real anatomical
variations.
Previous estimations of the difference between these
two definitions have been performed with methods of
*Author for correspondence.
114
unknown precision and with various definitions of the
shaft axis. The data concerning the true differences
between the two definitions of anteversion are therefore
unreliable. The main purpose of this work is to estimate
the differences between ANTEV 1 and ANTEV 2 by
methods that contribute little to the variation. A
secondary purpose is to draw attention to the real
anatomical relationship of the axis of the femoral neck.
Materials and methods
The estimations were made on a total of 33 unpaired
dissected femur specimens removed from adult corpses.
ANTEV 1 and ANTEV 2 are defined by the respective
neck axes described above, by the long shaft axis (the line
from the centre of the trochanteric mass to the centre of
the femoral condyles) and by the tangent to the back of
the femoral condyles.
ANTEV 2 was first measured by a conventional
method on 17 specimens (Norman, 1965). Two
radiographs were obtained of the upper ends of the
femora, one with vertical projection and one lateral. The
shaft axis was constructed on both radiographs as the
line from the middle of the trochanteric mass to the
middle of the femoral condyles. The perpendicular
distance from the centre of the femoral head to the shaft
axis was measured and the anteversion was measured by
a geometrical construction (Fig. 2). The precision of this
method was determined as the standard deviation of the
inter- and intrapersonal variation of four sets of
measurements.
On all 33 specimens, ANTEV 2 was determined on
EMI 5005 computed tomographic (CT) equipment. The
CT slices were made at a right angle to the shaft axis.
Superimpositions were made of a slice through the centre
of the femoral head and one through the middle portion
of the trochanteric mass. The shaft axis was marked as
the point equidistant from the most anterior and
The British Journal of Radiology, February 1989
Basic concepts of the femoral neck anteversion
Figure 1. Superimposition of CT slices showing the construction
of the neck axis according to ANTEV 2 definition (HC-2). On
the same slice the principal difference between the definitions is
shown by the neck axis according to ANTEV 1 (HC-1). The
difference in inclination of the neck axes by the two definitions
causes ANTEV 1 to be smaller than ANTEV 2. (HC = the head
centre.) The lines from the head centre to points 1 and 2 are
ANTEV 1 and ANTEV 2 neck axes, respectively, and points 1
and 2 are the midpoints of the respective dotted lines.
posterior points on the trochanteric mass (Fig. 1).
ANTEV 2 was measured as the angle between the neck
axis and a plane marking the dorsal aspects of the
femoral condyles. The precision of the CT measurements
was calculated by the following formula (Colquhoun,
1971):
var(^ — B) = var A + var B
The same equation is used to calculate the spread of
the difference between ANTEV 1 and ANTEV 2 caused
by the precision of the two definitions. In this equation
var(.4 — B) is the variance (square of one standard
deviation) of the paired differences between two sets of
measurements; var A and var B are the variances of the
precision of the two sets of measurements.
ANTEV 1 was determined on all 33 dissected, adult
femur specimens by a near to direct anatomical
projection of the angle as previously described (Reikeras
et al, 1985a) without correcting the values. (This is
identical to the projection used by Mesgarzadeh et al
(1987).) The precision of this method was previously
shown to have a standard deviation of 2.5°.
Results
The precision of the conventional method for
determining ANTEV 2 had a standard deviation of 4.8°
(mean of the standard deviations of inter- and
intrapersonal paired differences which were 4.7, 5.4 and
4.3°). The paired differences between the values obtained
by the conventional method and by CT had a standard
deviation of 5.1°. The precision of CT was calculated to
have a standard deviation of 1.7° (7(5.1 2 -4.8 2 )).
Vol. 62, No. 734
Figure 2. The geometrical construction for measurement of the
femoral neck anteversion (angle CAB) by the conventional
radiographic method. The shaft axis is marked in the shaft. The
perpendicular distance from the head centre to the shaft axis is
measured (lines AB and BC). The triangle ABC is constructed
and the angle CAB, which is equal to the anteversion, is
measured.
There was a close and linear relationship between the
definition of ANTEV 1 and ANTEV 2 (Fig. 3). The
mean paired difference was 4.2°, ANTEV 2 being larger
than ANTEV 1. The standard deviation of the difference
was 3.9°. The standard deviation of the difference
accounted for by the precision of the two definitions was
3.1°(V(2.52 + 1.72)).
Discussion
Norman (1969) was the first to point out the
anatomical difference between the head-neck and headshaft axes of the femoral neck and thus the discrepancy
between the theoretical definition and the design of
measuring methods. Dunn (1952), Dunlap et al (1953),
Magilligan (1956), Weiner et al (1978) and Ruby et al
(1979) have all described methods using the head-neck
axis and a definition implying a straight line between the
head centre, neck centre and the shaft axis. Recently,
Murphy et al (1987) and Mesgarzadeh et al (1987)
evaluated CT as a method for measuring the anteversion
byfirstusing the head-neck axis definition. To overcome
problems of variability in the neck anatomy, they defined
the neck axis in accordance with the head-shaft axis
without attending to the principal alteration in the
definition of the anteversion. In the international
literature, little attention has been given to the real
anatomical relationship of the femoral neck and to the
difference between the neck axis definitions. This may
cause confusion and inadvertent use of the measured
values.
To estimate the real anatomical variation or the real
difference between the two definitions it is necessary to
use measuring methods with known precision or with
115
A. Hoiseth, O. Reikeras and E. Fonstelien
of the methods. Disregarding the systematic difference, a
very good agreement was found between the two
definitions. They must, therefore, be considered to have
the same clinical and biomechanical implications and the
previously found individual variations must be due to the
error of the measuring methods. Provided correction is
made for the systematic difference, the two definitions
and corresponding measuring methods are comparable.
References
AV1
COLQUHOUN, D., 1971. Lectures on Biostatistics (Clarendon
Press, Oxford), p. 37.
10
DUNLAP, K., SHANDS, A. R. JR, HOLLISTER, L. C. JR, STUART
GAUL, J. JR & STREIT, H. A., 1953. A new method for
determination of torsion of the femur. Journal of Bone and
Joint Surgery, 35A, 289-311.
DUNN, D. M., 1952. Anteversion of the neck of the femur. A
method of measurement. Journal of Bone and Joint Surgery,
34B, 181-186.
AV2
Figure 3. Scattergram between ANTEV 1 (AVI) and ANTEV 2
(AV2) showing the spread of the differences and the linear
relationship between the definitions. The dotted line is drawn at
45° and intersects the base line at the mean of the paired
differences.
very high precision. In the latter case the methods do not
contribute substantially to the variation. We have
previously determined the precision of a method for
determining ANTEV 1 (Hoiseth et al, 1989). However,
the precision of methods for determining ANTEV 2 has
always been unknown. Furthermore, while ANTEV 1
can be determined by a near to correct projection of the
anteversion, no such simple and direct method is
available for ANTEV 2.
We have determined the precision of a conventional
approach previously described (Norman, 1965) and a CT
method which we designed. We found the latter to have a
high precision. Murphy et al (1987) have also described a
very similar method for determination of ANTEV 2; this
differs from ours in the location of the intersection
between the neck and shaft axis. We have used Norman
and Billing's definitions which locate this point in the
middle of the trochanteric mass. Murphy et al (1987),
however, located this point at the base of the femoral
neck which is in the distal portion of the trochanteric
mass at the junction with the shaft. Murphy et al (1987)
found precision of the same order as in the present study.
Computed tomography therefore seems suitable for our
purpose.
Our findings confirm the principal anatomical
difference between the two definitions of anteversion.
Contrary to Henriksson (1980) and Reikeras et al
(1985b), the present study showed a small spread of
differences between the two definitions expressed by a
small standard deviation. Furthermore, a substantial
part of this variation was accounted for by the precision
116
View publication stats
GROTE, R., ELGETI, H. & SAURE, D., 1980. Bestimmung des
Antetorsionswinkels
am Femur
mit der axialen
Computertomographie. Rontgenblatter, 33, 31-42.
HENRIKSSON, L., 1980. Measurement of femoral neck
anteversion and inclination. A radiographic study in children.
Ada Orthopaedica Scandinavica Supplementum, 186, 30.
HERRLIN, K. & EKELUND, L., 1983. Radiographic measurement
of the femoral neck anteversion. Comparison of two
simplified procedures. Acta Orthopaedica Scandinavica, 54,
141-147.
HOISETH, A., REIKERAS, O. & F0NSTEUEN, E., 1989. Evaluation
of three methods for the measurement of the femoral neck
anteversion. Acta Radiologica Scandinavica, 30, in press.
MAGILLIGAN, D. J., 1956. Calculations of the angle of
anteversion by means of horizontal lateral roentgenography.
Journal of Bone and Joint Surgery, 38 A, 1231-1246.
MESGARZADEH, M., REVESZ, G. & BONAKDARPOUR, A., 1987.
Femoral neck torsion angle measurement by computed
tomography. Journal of Computer Assisted Tomography, 11,
799-803.
MURPHY, S. B., SIMON, S. R., KIJEWSKI, P. K., WILKINSON, R. H.
& GRISCOM, N. T., 1987. Femoral anteversion. Journal of
Bone and Joint Surgery, 69A, 1169-1176.
NORMAN, O., 1965. Beskrivande geometri som hjalpmedel vid
bestamning av collum-anteversions-och—diafysvinkeln samt
fracturvinkeln. Nordisk Medicin, 73, 446-447 (in Swedish).
1969.
Matning av collumanteversionsvinkeln. En
principiell diskusjon. Nordisk Medicin, 82, 991-992 (in
Swedish).
REIKERAS, O., HOISETH, A. & REIGSTAD, A., 1985a. Evaluation
of the Dunlap/Rippstein method for determination of
femoral neck angles. Acta Radiologica Diagnosis, 26, 177—
179.
1985b. Femoral anteversion measured by the Dunlap/
Rippstein and Norman methods. Acta Radiologica Diagnosis,
26, 303-305.
RUBY, L., MITAL, M. A., O'CONNOR, J. & PATEL, U., 1979.
Anteversion of the femoral neck. Comparison of methods of
measurement in patients. Journal of Bone and Joint Surgery,
61A, 46-51.
WEINER, D. S., COOK, A. J., HOYT, W. A. Jr & ORAVEC, C. E.,
1978. Computed tomography in the measurement of femoral
anteversion. Computed Tomography, 1, 299-306.
The British Journal of Radiology, February 1989
Basic concepts of femoral neck anteversion: comparison of
two definitions
By *Arne Hoiseth, M D , tOlav Reikeras, M D and ttErik Fonstelien, MSc
Department of Diagnostic Radiology, tDepartment of Surgery, Orthopedic Section and ttDepartment of
Clinical Physiology, University of Oslo, Ulleval Hospital, 0407 Oslo 4, Norway
(Received June 1988 and in revised form October 1988)
Abstract. Femoral neck anteversion is determined by the neck, shaft and knee axes. It is commonly assumed that the neck axis is a
straight line connecting the centre of the femoral head, the centre of the femoral neck and the axis of the femoral shaft. However, the
line through the centre of the femoral head and neck crosses anterior to the axis of the femoral shaft. A distinction has therefore to
be made between two principal different definitions of anteversion, denoted ANTEV 1 and ANTEV 2 in this paper, depending on
the precise definition of the neck axis. Previous studies have indicated substantial differences between these definitions. The present
study, using precise measuring methods, shows that the definitions have a systematic but small spread of differences. The large
individual variation previously found between the two definitions is therefore caused mainly by the measuring methods and to a
lesser extent by real anatomical variations.
The femoral neck axis is traditionally considered to be a
straight line connecting the centre of the femoral head
and the centre of the femoral neck with the axis of the
femoral shaft (Dunn, 1952; Dunlap et al, 1953;
Magilligan, 1956; Weiner et al, 1978; Ruby et al, 1979).
However, the line from the centre of the femoral head to
the centre of the femoral neck, the head-neck axis,
usually passes in front of the axis of the femoral shaft
(Norman, 1969; Grote et al, 1980) and therefore differs in
principle from the definition using the line from the
centre of the femoral head to the intersection with the
shaft axis (head-shaft axis) (Fig. 1). Two different
definitions of anteversion can therefore be made,
depending on whether the head-neck or the head-shaft
axes are used.
In this work the first angle is denoted ANTEV 1 and
the latter ANTEV 2 in accordance with Henriksson
(1980). It has previously been shown that ANTEV 2 is
larger than ANTEV 1 (Grote et al, 1980; Henriksson,
1980; Herrlin & Ekelund, 1983; Reikeras et al, 1985b).
Previous studies have also shown a large spread of
differences (Henriksson, 1980; Reikeras et al, 1985b).
In both practical and theoretical contexts, it is
important to determine the anatomical and
biomechanical implications of the two angles. In this
context, it is the spread of the difference between the two
definitions that is most relevant. A systematic difference
can be dealt with by correcting the values and therefore
has few clinical or biomechanical implications. The
spread of the differences may, however, indicate
differences of importance. Such a spread of the measured
differences may, however, be due to poor precision of the
measuring methods rather than to real anatomical
variations.
Previous estimations of the difference between these
two definitions have been performed with methods of
*Author for correspondence.
114
unknown precision and with various definitions of the
shaft axis. The data concerning the true differences
between the two definitions of anteversion are therefore
unreliable. The main purpose of this work is to estimate
the differences between ANTEV 1 and ANTEV 2 by
methods that contribute little to the variation. A
secondary purpose is to draw attention to the real
anatomical relationship of the axis of the femoral neck.
Materials and methods
The estimations were made on a total of 33 unpaired
dissected femur specimens removed from adult corpses.
ANTEV 1 and ANTEV 2 are defined by the respective
neck axes described above, by the long shaft axis (the line
from the centre of the trochanteric mass to the centre of
the femoral condyles) and by the tangent to the back of
the femoral condyles.
ANTEV 2 was first measured by a conventional
method on 17 specimens (Norman, 1965). Two
radiographs were obtained of the upper ends of the
femora, one with vertical projection and one lateral. The
shaft axis was constructed on both radiographs as the
line from the middle of the trochanteric mass to the
middle of the femoral condyles. The perpendicular
distance from the centre of the femoral head to the shaft
axis was measured and the anteversion was measured by
a geometrical construction (Fig. 2). The precision of this
method was determined as the standard deviation of the
inter- and intrapersonal variation of four sets of
measurements.
On all 33 specimens, ANTEV 2 was determined on
EMI 5005 computed tomographic (CT) equipment. The
CT slices were made at a right angle to the shaft axis.
Superimpositions were made of a slice through the centre
of the femoral head and one through the middle portion
of the trochanteric mass. The shaft axis was marked as
the point equidistant from the most anterior and
The British Journal of Radiology, February 1989
Basic concepts of the femoral neck anteversion
Figure 1. Superimposition of CT slices showing the construction
of the neck axis according to ANTEV 2 definition (HC-2). On
the same slice the principal difference between the definitions is
shown by the neck axis according to ANTEV 1 (HC-1). The
difference in inclination of the neck axes by the two definitions
causes ANTEV 1 to be smaller than ANTEV 2. (HC = the head
centre.) The lines from the head centre to points 1 and 2 are
ANTEV 1 and ANTEV 2 neck axes, respectively, and points 1
and 2 are the midpoints of the respective dotted lines.
posterior points on the trochanteric mass (Fig. 1).
ANTEV 2 was measured as the angle between the neck
axis and a plane marking the dorsal aspects of the
femoral condyles. The precision of the CT measurements
was calculated by the following formula (Colquhoun,
1971):
var(^ — B) = var A + var B
The same equation is used to calculate the spread of
the difference between ANTEV 1 and ANTEV 2 caused
by the precision of the two definitions. In this equation
var(.4 — B) is the variance (square of one standard
deviation) of the paired differences between two sets of
measurements; var A and var B are the variances of the
precision of the two sets of measurements.
ANTEV 1 was determined on all 33 dissected, adult
femur specimens by a near to direct anatomical
projection of the angle as previously described (Reikeras
et al, 1985a) without correcting the values. (This is
identical to the projection used by Mesgarzadeh et al
(1987).) The precision of this method was previously
shown to have a standard deviation of 2.5°.
Results
The precision of the conventional method for
determining ANTEV 2 had a standard deviation of 4.8°
(mean of the standard deviations of inter- and
intrapersonal paired differences which were 4.7, 5.4 and
4.3°). The paired differences between the values obtained
by the conventional method and by CT had a standard
deviation of 5.1°. The precision of CT was calculated to
have a standard deviation of 1.7° (7(5.1 2 -4.8 2 )).
Vol. 62, No. 734
Figure 2. The geometrical construction for measurement of the
femoral neck anteversion (angle CAB) by the conventional
radiographic method. The shaft axis is marked in the shaft. The
perpendicular distance from the head centre to the shaft axis is
measured (lines AB and BC). The triangle ABC is constructed
and the angle CAB, which is equal to the anteversion, is
measured.
There was a close and linear relationship between the
definition of ANTEV 1 and ANTEV 2 (Fig. 3). The
mean paired difference was 4.2°, ANTEV 2 being larger
than ANTEV 1. The standard deviation of the difference
was 3.9°. The standard deviation of the difference
accounted for by the precision of the two definitions was
3.1°(V(2.52 + 1.72)).
Discussion
Norman (1969) was the first to point out the
anatomical difference between the head-neck and headshaft axes of the femoral neck and thus the discrepancy
between the theoretical definition and the design of
measuring methods. Dunn (1952), Dunlap et al (1953),
Magilligan (1956), Weiner et al (1978) and Ruby et al
(1979) have all described methods using the head-neck
axis and a definition implying a straight line between the
head centre, neck centre and the shaft axis. Recently,
Murphy et al (1987) and Mesgarzadeh et al (1987)
evaluated CT as a method for measuring the anteversion
byfirstusing the head-neck axis definition. To overcome
problems of variability in the neck anatomy, they defined
the neck axis in accordance with the head-shaft axis
without attending to the principal alteration in the
definition of the anteversion. In the international
literature, little attention has been given to the real
anatomical relationship of the femoral neck and to the
difference between the neck axis definitions. This may
cause confusion and inadvertent use of the measured
values.
To estimate the real anatomical variation or the real
difference between the two definitions it is necessary to
use measuring methods with known precision or with
115
A. Hoiseth, O. Reikeras and E. Fonstelien
of the methods. Disregarding the systematic difference, a
very good agreement was found between the two
definitions. They must, therefore, be considered to have
the same clinical and biomechanical implications and the
previously found individual variations must be due to the
error of the measuring methods. Provided correction is
made for the systematic difference, the two definitions
and corresponding measuring methods are comparable.
References
AV1
COLQUHOUN, D., 1971. Lectures on Biostatistics (Clarendon
Press, Oxford), p. 37.
10
DUNLAP, K., SHANDS, A. R. JR, HOLLISTER, L. C. JR, STUART
GAUL, J. JR & STREIT, H. A., 1953. A new method for
determination of torsion of the femur. Journal of Bone and
Joint Surgery, 35A, 289-311.
DUNN, D. M., 1952. Anteversion of the neck of the femur. A
method of measurement. Journal of Bone and Joint Surgery,
34B, 181-186.
AV2
Figure 3. Scattergram between ANTEV 1 (AVI) and ANTEV 2
(AV2) showing the spread of the differences and the linear
relationship between the definitions. The dotted line is drawn at
45° and intersects the base line at the mean of the paired
differences.
very high precision. In the latter case the methods do not
contribute substantially to the variation. We have
previously determined the precision of a method for
determining ANTEV 1 (Hoiseth et al, 1989). However,
the precision of methods for determining ANTEV 2 has
always been unknown. Furthermore, while ANTEV 1
can be determined by a near to correct projection of the
anteversion, no such simple and direct method is
available for ANTEV 2.
We have determined the precision of a conventional
approach previously described (Norman, 1965) and a CT
method which we designed. We found the latter to have a
high precision. Murphy et al (1987) have also described a
very similar method for determination of ANTEV 2; this
differs from ours in the location of the intersection
between the neck and shaft axis. We have used Norman
and Billing's definitions which locate this point in the
middle of the trochanteric mass. Murphy et al (1987),
however, located this point at the base of the femoral
neck which is in the distal portion of the trochanteric
mass at the junction with the shaft. Murphy et al (1987)
found precision of the same order as in the present study.
Computed tomography therefore seems suitable for our
purpose.
Our findings confirm the principal anatomical
difference between the two definitions of anteversion.
Contrary to Henriksson (1980) and Reikeras et al
(1985b), the present study showed a small spread of
differences between the two definitions expressed by a
small standard deviation. Furthermore, a substantial
part of this variation was accounted for by the precision
116
View publication stats
GROTE, R., ELGETI, H. & SAURE, D., 1980. Bestimmung des
Antetorsionswinkels
am Femur
mit der axialen
Computertomographie. Rontgenblatter, 33, 31-42.
HENRIKSSON, L., 1980. Measurement of femoral neck
anteversion and inclination. A radiographic study in children.
Ada Orthopaedica Scandinavica Supplementum, 186, 30.
HERRLIN, K. & EKELUND, L., 1983. Radiographic measurement
of the femoral neck anteversion. Comparison of two
simplified procedures. Acta Orthopaedica Scandinavica, 54,
141-147.
HOISETH, A., REIKERAS, O. & F0NSTEUEN, E., 1989. Evaluation
of three methods for the measurement of the femoral neck
anteversion. Acta Radiologica Scandinavica, 30, in press.
MAGILLIGAN, D. J., 1956. Calculations of the angle of
anteversion by means of horizontal lateral roentgenography.
Journal of Bone and Joint Surgery, 38 A, 1231-1246.
MESGARZADEH, M., REVESZ, G. & BONAKDARPOUR, A., 1987.
Femoral neck torsion angle measurement by computed
tomography. Journal of Computer Assisted Tomography, 11,
799-803.
MURPHY, S. B., SIMON, S. R., KIJEWSKI, P. K., WILKINSON, R. H.
& GRISCOM, N. T., 1987. Femoral anteversion. Journal of
Bone and Joint Surgery, 69A, 1169-1176.
NORMAN, O., 1965. Beskrivande geometri som hjalpmedel vid
bestamning av collum-anteversions-och—diafysvinkeln samt
fracturvinkeln. Nordisk Medicin, 73, 446-447 (in Swedish).
1969.
Matning av collumanteversionsvinkeln. En
principiell diskusjon. Nordisk Medicin, 82, 991-992 (in
Swedish).
REIKERAS, O., HOISETH, A. & REIGSTAD, A., 1985a. Evaluation
of the Dunlap/Rippstein method for determination of
femoral neck angles. Acta Radiologica Diagnosis, 26, 177—
179.
1985b. Femoral anteversion measured by the Dunlap/
Rippstein and Norman methods. Acta Radiologica Diagnosis,
26, 303-305.
RUBY, L., MITAL, M. A., O'CONNOR, J. & PATEL, U., 1979.
Anteversion of the femoral neck. Comparison of methods of
measurement in patients. Journal of Bone and Joint Surgery,
61A, 46-51.
WEINER, D. S., COOK, A. J., HOYT, W. A. Jr & ORAVEC, C. E.,
1978. Computed tomography in the measurement of femoral
anteversion. Computed Tomography, 1, 299-306.
The British Journal of Radiology, February 1989