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OJHAS Vol. 10, Issue 3:
(Jul-Sep 2011) |
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| Morphometry
of Glenoid Cavity |
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Mamatha T, Department
of Anatomy, Kasturba Medical College, Manipal University, Mangalore, India,
Shakuntala R. Pai, Department
of Anatomy, Kasturba Medical College, Manipal University, Manipal, India,
Murlimanju BV,
Department of Anatomy, Kasturba Medical College, Manipal University, Mangalore, India,
Sneha G. Kalthur, Department
of Anatomy, Kasturba Medical College, Manipal University, Manipal, India,
Mangala M. Pai Department
of Anatomy, Kasturba Medical College, Manipal University, Mangalore, India,
Brijesh Kumar Department
of Anatomy, Kasturba Medical College, Manipal University, Manipal, India. |
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Address for Correspondence |
Assistant Professor,
Department
of Anatomy,
Kasturba Medical
College,
Mangalore-575001
Karnataka State, India.
E-mail:
flutesnowmm@gmail.com |
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Mamatha T, Pai SR, Murlimanju BV, Kalthur SG, Pai MM, Kumar B. Morphometry
of Glenoid Cavity. Online J Health Allied Scs.
2011;10(3):7 |
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Submitted: Jul 17,
2011; Accepted: Oct 25, 2011; Published: Nov 15, 2011 |
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| Abstract: |
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Objectives:
Knowledge of the shape and dimensions of the glenoid are important in
the design and fitting of glenoid components for total shoulder arthroplasty.
An understanding of variations in normal anatomy of the glenoid is essential
while evaluating pathological conditions like osseous Bankart lesions
and osteochondral defects. Methods:
This study was done on 202 dry, unpaired adult human scapulae of unknown
sex belonging to the south Indian population. Three glenoid diameters
were measured, the superior-inferior diameter, anterior-posterior diameter
of the lower half and the anterior-posterior diameter of the upper half
of the glenoid. Based on a notch present on the anterior glenoid rim,
variations in the shape of the glenoid cavity were classified as inverted
comma shaped, pear shaped and oval. Results:
The average superior-inferior diameter on right and the left sides were
33.67±2.82mm and 33.92±2.87mm respectively. The average anterior-posterior
diameter of the lower half of the right glenoid was 23.35±2.04mm and
that of the left was 23.02±2.30mm. The mean diameter of the upper half
of the right glenoid was 16.27±2.01mm and that of the left was 15.77±1.96mm. Conclusion:
The dimensions of the glenoid observed in the present study were lesser
than those recorded in the studies done on other populations. This fact
may be taken into consideration while designing glenoid prostheses for
the south Indian population. The current study recorded a higher percentage
of glenoid cavities having the glenoid notch as compared to earlier
studies. While evaluating defects/lesions of the glenoid, this fact
could be useful.
Key Words:
Glenoid cavity; Total shoulder arthoplasty; Glenoid notch
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On the lateral
angle of the scapula is a shallow, pyriform articular surface- the glenoid
cavity also known as glenoid fossa of the scapula. The vertical diameter
of the glenoid cavity is the longest and it is broader below than above.
The shoulder joint is the most frequently dislocated joint in the body.
Dislocations with fractures of the glenoid are also quite common in
trauma. Along with repair of the labrum and reinforcing the capsule
by an overlapping repair and rearrangement of anterior muscles, total
shoulder replacement is also being used as treatment.(1) Today’s gold
standard for primary glenoid replacement is a cemented all-polyethylene
component.(2)
Various shapes
of the glenoid cavity have been described based on the presence of a
notch on the anterior glenoid rim. It has been found that if the notch
is distinct, then the glenoid labrum is not fixed to the bony margin
of the notch but bridges the notch itself. This could make the shoulder
joint less resistant to dislocating forces.(3) The morphology of the
glenoid cavity is highly variable. The shape of the glenoid cavity has
been diversely described as teardrop or pear-shaped, round, ovoid and
an inverted comma-shape depending on the presence or absence of a notch
on the anterior glenoid rim. The notch is better marked in the early
state of the bone, indicating the junction of the “coracoid” and
“scapular” parts of the articular surface, and the part above the
notch has a separate centre of ossification.(4) Anetzberger and Putz,
classified the shape of the glenoid cavity as teardrop-shaped glenoid
cavity, type IA and IB, with and without a notch respectively, from
an elongated oval shape type II.(5)
A glenoid osteochondral
defect occurs most often as a result of acute trauma and has higher
association with instability, labral tear and intra-articular bodies.(6)
Retrospective evaluation of roentgenograms of patients with unilateral
shoulder instability showed the osseous Bankart lesion to present in
20% of cases.(7) Burkhart and De Beer, described an inverted-pear glenoid,
in which a normally pear-shaped glenoid lost enough anterior-inferior
bone to assume the shape of an inverted pear.(8) A bone loss of more
than 21% of the superior-inferior glenoid length would cause instability
even after correct soft tissue repair.(9) Radiographic study on patients
with recurrent anterior shoulder instability showed osseous lesions
of the glenoid in 78.8% of cases.(10) Sugaya et al., evaluated the osseous
fragment quantitatively and its size was classified as large (>20%
of glenoid fossa), medium (5-20%) or small (<5%).(11)
The purpose
of the current study was to obtain the morphometrical data for the glenoid
cavity of the scapula specifically, the diameters of the glenoid cavity,
to study the various shapes of the glenoid cavity relevant to the South
Indian population and to compare the data obtained from the present
study with earlier report.
This study
was done on 202 dry, unpaired adult human scapulae of unknown sex. 98
scapulae belonged to the right side and 104 to the left side. Only the
bones with clear and intact glenoid cavity were used for the study.
The following parameters of the glenoid cavity were studied. (Fig.1)
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Superior-Inferior
glenoid diameter (SI): Represents the maximum distance from the
inferior point on the glenoid margin to the most prominent point of
the supraglenoid tubercle, which is also the maximum height of the glenoid
cavity
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Anterior-Posterior
glenoid diameter (AP-1): Represents the maximum breadth of the articular
margin of the glenoid cavity perpendicular to the glenoid cavity height
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Anterior-Posterior
glenoid diameter (AP-2): Represents the anterior-posterior diameter
(breadth) of the top half of the glenoid cavity at the mid-point between
the superior rim and the mid-equator.
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Shape of the
glenoid cavity: Shape made by the slightly raised rim of the glenoid
cavity.
The diameters
were measured in millimeters using sliding calipers. The shape of the
glenoid cavity was recorded in the following way. A piece of white sheet
was placed on the glenoid cavity and held firmly in position to trace
the shape of the glenoid cavity. The side of the point of a lead pencil
was rubbed along the rim of the glenoid cavity to get a tracing of the
shape of the glenoid cavity on the paper.
Fig. 1 (left):
Schematic diagram showing various diameters of the glenoid cavity. A-B:
Superior-Inferior diameter (SI), C-D: Anterior-Posterior diameter 1
(AP-1), E-F: Anterior-Posterior diameter 2 (AP-2) |
The mean and
standard error of the glenoid cavity in various dimensions were calculated.
The data were analyzed using the Statistical Package for the Social
Sciences (SPSS) version 15.0. Group and descriptive statistics were
calculated. The morphometric values of the two sides were analyzed using
an unpaired t-test. For comparison of the data obtained from the present
study with earlier published reports. One sample t-test was employed.
In the present
study, the Superior-Inferior diameter of the glenoid cavity on the right
side varied from 25mm to 42mm, with an average of 33.67 ± 2.82mm.
On the left side the Superior- Inferior diameter varied from 26mm to
40mm, with a mean of 33.92 ± 2.87mm.
In this study,
the AP-1 glenoid diameter of the right and left sides varied from 20mm
to 28mm and 18mm to 28mm respectively. The average AP-1 diameter of
the right glenoid was 23.35 ± 2.04mm and the average AP-1 diameter
of the left glenoid was 23.02 ± 2.30mm.The range for the AP-2 diameter
of the right glenoid cavity was 12mm to 22mm and the mean for the same
was 16.27±2.01mm. The AP-2 diameter for the left glenoid varied from
12mm to 21mm, while the mean for the left glenoid was 15.77±1.96mm.
(Table 1)
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Table 1: Comparison
of measurements of right and left glenoid |
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Parameter
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Range |
Mean |
Standard Deviation |
Statistical Significance |
P Value |
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Right |
Left |
Right |
Left |
Right |
Left |
Right |
Left |
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SI
diameter |
25-42mm |
26-40mm |
33.67mm |
33.92mm |
2.82 |
2.87 |
None |
None |
0.535 |
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AP-1
diameter |
20-28mm |
18-28mm |
23.35mm |
23.05mm |
2.04 |
2.30 |
None |
None |
0.286 |
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AP-2
diameter |
12-22mm |
12-21mm |
16.27mm |
15.77mm |
2.01 |
1.96 |
None |
None |
0.078 |
On the right
side, out of the total 98 glenoid cavities examined 33 were found to
have inverted comma shape. And the incidence of this shape was calculated
to be 34%. The number of glenoids having pear shape on the right side
was 45 and the incidence was found to be 46%. Oval glenoids were 20
in number on the right side and the incidence was 20%. On the left side,
glenoids with the inverted comma shape were 34 in number out of the
total 104 scapulae examined. The incidence of inverted comma shaped
glenoid was 33%. 45 glenoids on the left side were found to have the
pear shape and incidence of pear shaped glenoid was 43%. The oval glenoid
cavities were 25 in number and the incidence of oval glenoid was 24% (Table-2
and Fig.2).
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Table 2: Comparison
between shape of right and left glenoid |
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Shape of
glenoid |
Incidence of shape |
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Right glenoid |
Left glenoid |
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Inverted
comma |
34% |
33% |
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Pear |
46% |
43% |
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Oval |
20% |
24% |
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Fig. 2:
Photograph showing various shapes of the glenoid cavity |
In the present
study an effort has been made to find the average diameters of the glenoid
cavity of the scapula and the incidence of various shapes of the glenoid
cavity in the South Indian population. Several authors have attempted
to determine the glenoid diameters in the course of their research.
This has been performed in a variety of ways, including direct measurement
of dry scapulae, direct measurement of fresh or embalmed cadavers, radiographic
measurement of scapulae harvested from cadavers and radiographic measurement
in living patients. These studies have been performed on different populations.
In evaluating the data presented in this study, a comparison to work
by others reveals several differences as well as similarities.
In the present
study the average superior-inferior diameter of the right glenoid was
33.67 ± 2.82 mm and the average superior-inferior diameter of the left
glenoid was 33.92 ± 2.87 mm. Though the left glenoid value was slightly
more, it was not statistically significant. This shows that the length
of the right glenoid was slightly less than that of the left. The averages
were compared to the values recorded in other studies (refer Table 3). Iannotti et al., reported the superior-inferior diameter of the glenoid
to be 39 ± 3.5mm which was more than the value got in the present study.(12)
Mallon et al., and Von Schroeder et al., reported the SI diameter to
be 35 ± 4.1mm and 36 ± 4mm respectively. (13,14) Both these values
are higher than what was recorded in our study. Karelse et al., found
the SI to be 35.9 ± 3.6 mm which was more than what was recorded in
our study.(2)
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Table 3: Comparison
of Superior-Inferior diameter by various authors. |
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Observers |
No of specimens |
Mean SI diameter |
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Mallon et al (1992)13 |
28 |
35 ± 4.1mm |
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Iannotti
et al (1992)12 |
140 |
39 ± 3.5mm |
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Von
Schroeder et al (2001)14 |
30 |
36 ± 4mm |
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Churchill
et al (2001)15 |
Male-200 |
37.5 ± 2.2mm |
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Female-144 |
32.6 ±
1.8mm |
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Luis
Rios Frutos (2002)16 |
Male-65 |
36.08 ± 2.0mm |
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Female 38 |
31.17 ±
1.7mm |
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Ozer et al (2006)17 |
Male – 94 |
38.71 ± 2.71mm |
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Female- 92 |
33.79 ±
3.08mm |
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Karelse
et al (2007)2 |
40 |
35.9 ± 3.6mm |
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Present
study (2009) |
Right-98 |
33.67 ± 2.82mm |
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Left-104 |
33.92 ±
2.87mm |
Churchill et
al., Luis Rios Frutos and Ozer et al., measured the SI diameter
of the male and female glenoid separately. The average SI diameter of
the male glenoid measured by Churchill et al., was 37.5 ± 2.2mm, SI
diameter of male glenoid measured by Luis Rios Frutos was 36.08 ± 2.05
mm and that measured by Ozer et al., was 38.71 ± 2.71mm.(15-17) All
these three measurements were significantly higher than that reported
in the present study. The SI diameter of the female glenoid measured
by these three authors namely Churchill et al., Luis Rios Frutos and
Ozer et al., was 32.6 ± 1.8mm, 31.17 ± 0.17 mm and 33.79 ± 3.08 mm
respectively.(15-17) The findings of the present study agree with these
authors who have done the measurements on the female scapula. They had
not mentioned the side of the scapula. In our study the sex of the scapulae
was not known, therefore we could not measure them separately.
In our study
the average anterior-posterior diameter (AP-1) of the lower half of
the glenoid of the right side was 23.35 ± 2.04mm and that of the left
side was 23.02 ± 2.30 mm. This suggests that the right glenoid is broader
than the left glenoid. The combined average of both sides was 23.19
± 2.1mm. This was very close to what was observed in the female glenoids
studied by Churchill et al., Luis Rios Frutos and Ozer et al.(15-17)
Churchill et al., recorded the average AP-1 diameter to be 23.6 ± 1.5mm,
Luis Rios Frutos found it to be 22.31 ± 1.49mm and Ozer et al.,
got 22.72 ± 1.9mm. The values recorded for the AP-1 diameter for the
male glenoids were 27.8 ± 1.6mm by Churchill et al., 26.31 ±
1.57mm by Luis Rios Frutos, and 27.33 ± 2.4mm by Ozer et al.,.(15-17)
All these three values were higher than our combined average of both
right and left sides, 23.19 ± 2.1mm. The AP-1 diameter recorded by
Mallon et al., which was 24 ± 3.3mm was quite close to what was recorded
in the present study which was 23.19±2.1mm(13) Iannotti et al.,(12)
recorded 29±3.2mm, Von Schroeder et al.,(14) got 28.6±3.3mm and Karelse
et al.,(2) found the AP-1 diameter to be 27.2±3mm. All the three were
higher than what was observed in the present study. (Refer Table. 4)
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Table 4: Comparision
of the anterior-posterior (AP-1) diameter by various authors |
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Observers |
No of specimens |
Mean AP-1 diameter |
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Mallon
et al (1992)13 |
28 |
24 ± 3.3mm |
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Iannotti
et al (1992)12 |
140 |
29 ± 3.2mm |
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Von
Schroeder et al (2001)14 |
30 |
28.6 ± 3.3mm |
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Churchil
et al (2001)15 |
Male-200 |
27.8 ± 1.6mm |
| Female-144 |
23.6 ±
1.5mm |
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Luis
Rios Frutos (2002)16 |
Male-65 |
26.31 ± 1.5mm |
| Female -38 |
22.31±1.4mm |
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Ozer et al (2006)17 |
Male -94 |
27.33 ± 2.4mm |
| Female -92 |
22.72 ±
1.72mm |
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Karelse
et al (2007)2 |
40 |
27.2 ± 3.mm |
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Present
study (2009) |
Right-98 |
23.35 ± 2.04mm |
| Left-104 |
23.02 ±
2.30mm |
The average
anterior-posterior diameter (AP-2) of the upper half of the right glenoid
was 16.27 ± 2.01mm and that of the left glenoid was 15.77 ± 1.96mm
in the current study. This suggested that the right glenoid cavity was
slightly broader than the left glenoid cavity. The combined average
on both sides was 16.02 ± 2.0mm. This was much lower than what was
observed by Iannotti et al 1992, which was 23 ± 2.7mm.(12)
Various types
of glenoid cavity based on their shape were observed in the current
study. The percentage of occurrence of various shapes of the glenoid
cavity was recorded. We found that on the right side 34 % of the glenoids
had a distinct notch and were inverted comma-shaped, while on the left
side inverted comma shape was of 33 %. 46 % of the right glenoids were
pear-shaped with an indistinct notch and 43 % on the left side were
pear-shaped. On the right side 20% were oval and on the left side 24
% were oval without any recognizable notch. The comparison between right
and left showed that more glenoids on the left did not show any notch
and were oval in shape.
We compared
our study to that of Prescher and Klumpen.(3) In our study the percentage
of glenoids with the glenoid notch, that is, both indistinct and distinct
was 80% on the right side and 76% on the left side as compared to the
observation by Prescher and Klumpen 1997 who found it to be 55%. In
our study the oval glenoids comprised only of 20% on the right side
and 24% on the left side, were as Prescher and Klumpen observed that
45%of the glenoids did not have a notch and were therefore oval in shape.
Studies done on soft tissue specimens have shown that when the glenoid
notch is distinct, the glenoid labrum is often not attached to the rim
of the glenoid at the site of the notch.(3) This can be a predisposing
factor in anterior dislocation of shoulder joint.
Knowledge of
the shape and dimensions of the glenoid are important in the design
and fitting of glenoid components for total shoulder arthroplasty. An
understanding of variations in normal anatomy of the glenoid is essential
while evaluating pathological conditions like osseous Bankart lesions
and osteochondral defects. A recent study by Mathew et al., in south
India among type 2 diabetes mellitus patients recorded that 16.5% of
them suffered from frozen shoulder, 5.48% from periarthritis of the
shoulder and 3.55% from rotator cuff injury.(18) An increase in the
aging population accompanied by an increase in the incidence of type
2 diabetes mellitus, indicate that arthritic diseases of the shoulder
may become more common in the near future in the south Indian population.
By observing
the tables in the discussion it can be implied that the values observed
in the present study, though coinciding with that of some of the studies
are mostly less than that recorded by many of the observers. The average
supero-inferior glenoid diameter in our study is 33-34 mm, however these
anatomical specimens were non-arthritic which mean that the average
supero-inferior glenoid diameter in an arthritic glenoid would be lesser
due to bone loss. Moreover, the diameter would further decrease following
reaming of the glenoid. The standard available smallest glenoid component
in the market is 40mm which may not fit the glenoid in our study population.
This implies that the smaller dimensions of the glenoid cavities in
the South Indian population may have to be taken into consideration
while designing and fitting glenoid components for total shoulder arthroplasty
in this population.
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- Prescher A, Klumpen
T. The glenoid notch and its relation to the shape of the glenoid cavity
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- Mallon WJ, Brown
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the scapula. Clin Orthop Relat Res 1992;277:142-154.
- von Schroeder HP,
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JJ, Kotschi H. Glenoid size, inclination, and version: An anatomic study.
J Shoulder Elbow Surg 2001;10:327-332.
- Frutos LR. Determination
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indigenous population. Am J Forensic
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skeletons from East Anatolia. Coll Antropol 2006;30:415-419.
- Mathew AJ, Nair
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