EBM project – Special Tests for Shoulder Labral Pathologies
Yohan Kim
Intro:
Labral tears of the shoulder labrum can be caused by trauma or repetitive shoulder
motion. Mechanisms of trauma include falling onto an outstretched arm or the shoulder, a
sudden pull to the shoulder, a sudden upward motion, and a direct blow to the shoulder.
Repetitive shoulder motion injuries are often associated with sports injuries that occur from
activities such as pitching a baseball, throwing a football or lifting weights. The symptoms
that might indicate a labral injury may include a catching sensation, clicking or locking in the
shoulder, pain within the joint, increased pain with movement, decreased range of motion of
the shoulder and arm, and susceptibility to dislocation.
Detecting labral tears in a shoulder can be difficult in a clinical evaluation. It is true
that there are methods of detecting such problems. Methods such as arthroscopy and MRI
(Magnetic Resonance Imaging) can be used to check and diagnose a patient. Arthroscopy is
known to be the most accurate method (gold standard) for diagnosing labrum related
pathologies, and MRI can also confirm many diagnoses with a high degree of reliability.1
However, these methods are not very cost efficient. If the results show that the patient does
not have the suspected problems, the patient would end up using more money than they
should have used for clinical examination. Therefore, it is not easy for patients to decide
whether to use these methods or not.
In contrast to these methods, diagnostic tests have been developed for the purpose of
detecting physical problems without having to go through expensive examinations. By
utilizing these tests, it may be possible to help patients avoid unnecessary expenses.1 Out of
those diagnostic tests, the anterior apprehension test, the relocation test, and the jerk are tests
which have been described for diagnosing labrum related pathologies of the shoulder.1
For the anterior apprehension test, the patient is either in supine or seated position
with their test arm abducted to 90 degrees and elbows flexed to 90 degrees. The shoulder is
passively moved into maximum external rotation with pressure applied anteriorly.3 A positive
outcome for this test is pain and/or apprehension.
The relocation test, also known as the Jobe’s test, is usually used after the
apprehension test. For this test, the patient is supine with the arm abducted to 90 degrees and
elbows flexed to 90 degrees. As the arm is externally rotated, the humeral head is pressed
down posteriorly.4 A positive outcome is relief of pain and apprehension when compared to
the outcomes of the apprehension test.
The jerk test is also carried out with the patient in the supine position. The test arm is
abducted 90 degrees and horizontally adducted 90 degrees. An axial load is placed on the
humerus while the arm is placed in internal rotation. Then the arm is further adducted
horizontally.5 A positive outcome for this test is clicking or clunking accompanied with or
without pain.
These tests have been used by physicians and athletic trainers for many years.
However, most of these tests are only theoretical and have not been tested for their
significance in detecting specific symptoms. Nevertheless, they are widely used for
diagnosing patients. In order to clarify the true efficiency and reliability of these tests, and to
ensure that the medical service providers are using the most effective tests to diagnose
patients, further research and comparison of the sensitivity and specificity of the diagnostic
tests is needed.
In order to further clarify and compare the reliability of the diagnostic tests, research
articles have been gathered, compared, and analyzed in order to determine the sensitivity,
specificity, positive likelihood ratio and negative likelihood ratio for each test.
Statistic comparison results and average for each test:
Apprehension
Fowler et al. (SLAP)
Fowler et al. (Labral Tear)
Oh et al. (SLAP)
Guanche et al. (Labral Tear)
Guanche et al. (SLAP)
Average:
Sensitivity
28.6
31.6
62
40
30
38.44
Relocation
Fowler et al. (SLAP)
Fowler et al. (Labral Tear)
Sensitivity Specificity
60
35.6
57.9
36.8
Oh et al (SLAP)
Guanche et al. (Labral Tear)
Guanche et al. (SLAP)
Specificity
68.9
70.7
42
87
63
66.32
+LR
0.92
1.08
1.07
3.08
0.81
1.39
-LR
1.04
0.97
0.90
0.69
1.11
0.94
+LR
0.93
0.92
-LR
1.12
1.14
1.04
0.64
1.02
44
44
36
54
87
63
0.96
3.38
0.97
75
59
53.70
40
54
52.91
1.25
1.28
1.38
0.63
0.76
0.91
Sensitivity Specificity
+LR
73
36.50
98
Kim et al. 2004 (Labral Tear)
85
5.98
89.7
Nakagawa et al. (Labral Tear)
80
1.25
25
Average:
62.57
87.67
14.58
* +LR: Positive likelihood ratio, -LR: Negative likelihood ratio
-LR
0.28
Nakagawa et al. (Labral Tear)
Morgan et al.(SLAP)
Average:
Jerk
Kim et al. 2005 (Labral Tear)
0.12
0.94
0.44
Discussion:
1) Apprehension test:
A total of three articles had statistics for the anterior apprehension test. They were
written by Fowler et al., Oh et al., and Guanche et al. The research carried out by Fowler et al.
and Guanche et al. shows that the researchers divided labral pathologies in to two different
groups, SLAP(superior labral tear from anterior to posterior) lesion and other labral tears that
do not fit into SLAP lesions. The research by Oh et al. focused only on SLAP lesions.
Overall average sensitivity of the anterior apprehension test is 38.44 and average
specificity is 66.32. The average positive likelihood ratio is 1.39, and the average negative
likelihood ratio is 0.94. The statistics indicate that the anterior apprehension test is not very
reliable for diagnosing patients.
When the statistics are looked at separately, it can be seen that the sensitivity is
highest and specificity is lowest in the research by Oh et al. The high sensitivity may be
because Oh et al. used subjects who had already undergone arthroscopy and were clinically
diagnosed with either a SLAP lesion or other pathologies, whereas the other two studies were
carried out on patients before they underwent arthroscopy. The low specificity may be
because of the overall age of patients. The subjects Oh et al. recruited had more elderly
people (over 40 years old) than younger people (below 40). Further into the article, Oh et al.
shows that it is much more difficult to get positive or negative results from patients over 40
years old. This may have resulted in the low specificity.
Guanche et al. had the highest specificity out of all the research articles. However,
when the patients were diagnosed through arthroscopy, it showed that some patients had more
than one of the pathologies. The number of pathologies counted was 152, and the number of
labral tears counted was 20. The low number of labral tears compared to other pathologies,
and the patients having more than one of the pathologies may be why the specificity was so
high for Guanche et al.
2) Relocation test:
A total of five articles had statistics for the anterior apprehension test. They were
written by Fowler et al., Oh et al., Guanche et al., Nakagawa et al., and Morgan et al. The
research carried out by Fowler et al. and Guanche et al. shows that the researchers divided
labral pathologies in to either the SLAP lesion group or the labral tears group. The research
by Oh et al. and Morgan et al. focused only on SLAP lesions while Nakagawa et al. focused
on labral tears.
Overall average sensitivity of the relocation test is 53.70 and average specificity is
52.91. The average positive likelihood ratio is 1.38, and the average negative likelihood ratio
is 0.91. The statistics show that the relocation test is not very reliable for diagnosing patients.
Though there may be many causes to this, one of the reasons may be because the relocation
test relies on changes in perceived pain to diagnose patients. In most cases, the patients had
more than one of the pathologies. This may have made it much more difficult to make
diagnoses.
Fowler et al. had the lowest specificity for both SLAP lesion and labral tears. This
may be because only 7 patients out of 101 patients had isolated SLAP lesion. The research
also says that 72 patients had more than one shoulder pathologies. The high number of
patients with multiple pathologies may have created difficulties in accurately diagnosing
patients.
Guanche et al. had the highest specificity for labral tears. Of all the pathologies
recorded, 20 labral tears were recorded from a total of 152 pathologies. When considering the
low number of labral tears, this may be why the specificity was so high for Guanche et al.
Nakagawa et al. had the highest sensitivity for labral tears. The research mentions
that they recruited patients that were all involved in throwing sports and had undergone
surgery. Of the 54 patients, 53 were baseball players and 1 of the patients was a javelin
thrower. And also, out of 54 patients, 24 had superior labrum injuries and 30 had normal
superior labrums. Though the patients did have more than just one of the pathologies, the
article does not mention the patients having any other type of labrum related pathologies.
Therefore, the patients either had superior labral injuries or had no labral injuries at all. The
fact that they played the same sport may also mean that they had the same injuries. These
may be the reason for the high sensitivity.
3) Jerk test:
A total of three articles had statistics for the jerk test. They were written by Kim et
al.(2004), Kim et al.(2005), and Nakagawa et al. All of the research focused on labral tears.
Overall average sensitivity of the jerk test is 62.57 and average specificity is 87.67.
The average positive likelihood ratio is 14.58, and the average negative likelihood ratio is
0.44. The statistics show that the jerk test is not very reliable for its sensitivity, but it shows
promising statistics for its specificity.
The research by Kim et al. in 2004 showed the highest percentage for sensitivity. This
may have something to do with the patients recruited. The study says that the criteria for
recruited patients who have been treated for posteroinferior instability. The posteroinferior
instability may have meant more patients with posteroinferior labral pathologies were likely
to be recruited.
The research by Kim et al. in 2005 showed the highest specificity. Unlike the
research in 2004, the subjects recruited 172 patients who have undergone arthroscopic
examination at the ‘Samsung Medical Center’. This may explain the lower sensitivity
percentage compared to the research done in 2004. The subjects were evaluated through
arthroscopy and any abnormal lesions were recorded. The patients identified with
posteroinferior labral lesions were divided into two groups. The groups were 1)
predominantly posterior, and 2) predominantly inferior. All the subjects, not just the ones
with posteroinferior labral lesions, underwent testing through the jerk test. Though there were
also patients with superior labral lesions, the research was mainly focused on posteroinferior
labral tears. The jerk test was able to identify 22 out of 25 shoulders correctly for
posteroinferior labral pathologies, and missed 8 shoulders with positive posteroinferior labral
pathologies. All in all, these statistics show that the jerk test may be reliable for identifying
negative results.
In the case of Nakagawa et al., their research showed the lowest sensitivity of the
three articles. This may be because of the type of labral pathologies the patients had. For the
two Kim et al. articles, most of the patients had posteroinferior labral pathologies. However,
for Nakagawa et al., most of their patients had superior labral pathologies. Out of the 54
patients they recruited, 24 had superior labrum injuries and 30 had normal superior labrums.
No patient had posteroinferior labral pathologies. This seems like the reason for the
extremely low sensitivity. And for the strangely high specificity, it may be because of the
high number of subjects without labral pathologies. More than half of the patients did not
have labral pathologies.
Conclusion:
From the results gathered, it can be said that the apprehension test and the relocation
test are not reliable for diagnosing labral pathologies. The jerk test shows promising
percentages for specificity and positive likelihood ratio. However, it would be difficult to say
that the jerk test would be ideal for diagnosing every type of labral pathology. From the
comparison of articles, it seems clear that the jerk test is reliable when it is used for ruling in
posteroinferior labral tears. Though there is a possibility for the jerk test to be reliable in
ruling out posteroinferior labral tears, further studies seem to be needed to clarify its
reliability. Therefore, it would be advised that the jerk test be used for ruling in
posteroinferior labral tears, and examiners should not confirm the possibility of posterolateral
labral tears based on just the findings from the jerk test.
Reference:
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Posteroinferior Labral Lesion of the Shoulder-A Comparison to the Jerk Test. American
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2. Guanche CA, Jones DC. 2003. Clinical testing for tears of the glenoid labrum.
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