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FACULTEIT GENEESKUNDE EN FARMACIE
Do patients with shoulder instability due to isolated anterosuperior capsuloligamentous lesions have a different postoperative rehabilitation course and outcome than the patients with other capsuloligamentous lesions?
Thesis neergelegd voor het behalen van de graad van Master in de Geneeskunde
Tom Depovere
Academiejaar 2013 - 2014
Promotor: Prof. Dr. N. Pouliart
1
Table of contents
Acknowledgements ...................................................................................................................... 2
Article .......................................................................................................................................... 3
Abstract. .............................................................................................................................................. 3
Introduction. ........................................................................................................................................ 4
Methods and materials. ...................................................................................................................... 6
Results. ................................................................................................................................................ 8
Discussion. ......................................................................................................................................... 15
Conclusion. ........................................................................................................................................ 17
References. ........................................................................................................................................ 18
Appendix ................................................................................................................................... 20
Background information on shoulder anatomy. ............................................................................... 20
2
Acknowledgements
My studies were not possible without the support and help of many people. First I would like
to thank my promotor, Prof. Dr. Nicole Pouliart for her assistance, guidance, support and
dedicated involvement with respect to this paper.
I would especially like to thank my parents and 2 sisters for always offering their endless
support and help during my studies.
Also a thank you for Olivier Beuckelaers who offered me the possibility to combine my
studies with my professional activities and who always supported me.
I could also always count on the support of my friends.
And last but not least I would like to thank my wife and 2 children for their cheerful support
and patience.
3
Article
Abstract.
Introduction. Minor or anterosuperior shoulder instability (SI) is a relatively new concept.
Until now, not many studies investigated the specific pattern of minor shoulder instability.
Moreover, there is to our knowledge not yet a study that compared SI with only isolated
anterosuperior capsuloligamentous lesions (MSI) and SI with at least an anteroinferior
capsuloligamentous lesion (CSI).
Purpose: The purpose of this study was to compare these 2 types of SI in terms of the
postoperative rehabilitation, the return to work and sport, and the outcome after
arthroscopic surgery. Our hypothesis was that the postoperative rehabilitation course and
return to work and sport was longer for patients with MSI and that they had a worse
outcome than patients with CSI.
Methods and materials: 87 patients who underwent an arthroscopic surgery as treatment
for the final diagnosis of SI were willing to return a survey. The subjects were divided in 2
groups. Group I consisted of 29 patients with only anterosuperior capsuloligamentous
lesions. Group II consisted of 58 patients with at least an anteroinferior capsuloligamentous
lesion. The survey included a questionnaire as well as the Oxford Shoulder Instability Score
(OSIS) and the Western Ontario Shoulder Instability index (WOSI).
Results: The pain at rest, night pain and pain during overhead activities (p=0,036)
disappeared slower in group I than group II. The return to normal subjective range of motion
(ROM) shows less differences between the 2 groups. Patients in group I returned slower to
their professional activities (p=0,015) and to their same sport. Group I scored worse on the
OSIS (p=0,034) and WOSI.
Conclusion: We can conclude that patients with MSI have poorer prospects when it comes
to postoperative rehabilitation, return to work and sport, and outcome compared to
patients with the CSI.
Key words: Shoulder instability – Minor shoulder instability – Return to work and sport –
Outcome score.
4
Introduction.
Shoulder instability (SI) is a very frequent pathology of the shoulder that has a variety of
clinical presentations.5 The glenohumeral joint is the most often dislocated joint in the body
due to the combination of a large range of motion (ROM) and an insufficient bony
stabilization. The stability of the shoulder is provided by a complex interaction between
static and dynamic mechanisms.8 When one of these static or dynamic stabilizers is damaged
by trauma or overuse, the shoulder has an increased risk of injuries.5 An imbalance between
the stabilizers can result in a wide spectrum of clinical symptoms.1, 2
SI is usually still
classified in Traumatic Unidirectional Bankart lesion treated with Surgery (TUBS) and
Atraumatic Multidirectional Bilateral treated with Rehabilitation and if surgery is required an
Inferior capsular shift or closure of the rotator Interval (AMBRII). This classification is
however not capable to include all the different types of instability, especially a group of
“subtle” conditions which may be identified as minor shoulder instability (MSI).1
Subtle, occult and anterosuperior instability are all synonyms used in the literature for MSI.2
MSI is a relatively new concept and until now, not many studies investigated the specific
pattern. Castagna et al. defined MSI as shoulder pain secondary to shoulder laxity, which
cannot be defined as TUBS or AMBRII. This pathological condition included an Acquired
Instability in Overstressed Shoulder (AIOS) and an Atraumatic Minor Shoulder Instability
(AMSI).1
MSI can occur in both athletic and non athletic persons under the age of 40.2 It may be
caused by microtrauma (AIOS) or by anatomic variants combined with muscle atrophy
(AMSI).1
AIOS describes a pathological condition that is related to overstress where the
superior part of the capsuloligamentous complex is involved. It is most common in overhead
athletes and young workers who perform heavy overhead work. To date there are various
theories on how these overhead activities can lead to this pathology. They suspect that the
middle glenohumeral ligament (MGHL) plays a major role in the development of AIOS.1 AMSI
is a very rare entity and is rarely described in the literature. These patients have pain of the
shoulder after a period of inactivity like a pregnancy or an immobilization.1 They often
demonstrate anatomical variants of the MGHL such as absence, hypoplasia or a Buford
complex.11, 12
Clinical examination usually reveals a reduced ROM, especially in elevation, due to pain.1, 2, 3
Other standard shoulder tests are not specific for this pathology. Castagna et al. propose in
their study the Castagna test for MSI. In this test the patient is positioned with 45° of
glenohumeral abduction. The arm is in maximal external rotation and the test is positive
when there is pain at the moment of relocation.1
Until now the diagnosis of MSI is most of the time only possible after an arthroscopic
procedure since the symptoms are often not specific and the clinical examination can be
5
confounding.2 According to Castagana et al. patients with MSI complain of pain in the
posterior-superior aspect of the affected, generally dominant, shoulder. The pain is often
diffuse and difficult to pinpoint. Patients also describe snapping and popping, “dead arm”,
painful subluxation or transient locking.1 Nordenson et al. describe that MSI also often
presents as a subacromial impingement syndrome.2
The main pathologic process of MSI can be identified at the level of the anterosuperior part
of the labrum, especially the MGHL complex.1 Castagna et al. believe that the anatomical
variants of the MGHL cannot be totally benign. In MSI this ligament can appear as
hyperemia, fraying, stretching, loosening, thinning, hypoplasia or even absent.1
It is often
difficult to distinguish between a normal variant and a pathological condition, even for an
experienced shoulder surgeon.
An indirect sign of MSI is the distance between the long head of the biceps muscle and the
rotatorcuff. This distance increases in case of MSI. It may seem that the capsular volume has
increased and the drivethrough sign may be positive in patients with MSI.1
An isolated tear in
the anterosuperior labrum can also be a subtle cause of a painful shoulder.3 This injury is
however usually extended to either the origin of the long head of the biceps muscle or
anterior to posterior (Superior Labral Anterior Posterior (SLAP)-lesion).19
The treatment of MSI is surgical repair of the shoulder stability.1, 2
The rehabilitation takes 6 to 9 months. Castagna et al. established a permanent restriction in
external rotation of a few degrees.1 However, this was not the case in the studies of
Nordenson et al. and Garofalo et al.2, 3
Our hypothesis was that the postoperative rehabilitation course and return to work and
sport was longer for the MSI patients and that they had a worse outcome than the patients
with classic shoulder instability (CSI).
The purpose of our retrospective study was to compare the group of patients with MSI with
those with CSI and this for the postoperative rehabilitation course, the time to resume work
and sport, and the outcome after arthroscopic surgery. To the best of our knowledge this
comparison has not been done before.
6
Methods and materials.
Between 1994 and 2012 290 patients underwent a shoulder arthroscopy for the final
diagnosis of any type of SI in our institution. All arthroscopies were performed by 2
experienced shoulder surgeons. The arthroscopic procedure was performed with the
patients in lateral decubitus position with the arm placed in a shoulder holder with traction.
Routine anterosuperior and posterolateral portals were created to inspect the entire joint.
All these 290 patients were invited to participate in our study by means of a letter. Of the
290 patients, 6 patients were deceased and 125 patients could not be reached because of
lack of current contact information. Of the remaining 159 patients, 72 declined to
participate, either because of lack of interest (30) or due to professional time restrictions
(42). Therefore, the present study group consists of 87 patients (figure 1).
Our research population consisted of 49 men (56,3%) and 38 women (43,7%). The mean age
at time of surgery was 31,44 ± 10,40 years (range 16-60). The dominant arm was affected in
59 patients (67,8%). None of the patients was ambidextrous.
The study group was divided into 2 groups based on the injuries determined during the
shoulder arthroscopy. 29 patients (33,3%) had only isolated anterosuperior
capsuloligamentous lesions and they form our study group (group I - MSI). 58 patients
(66,7%) had at least an anteroinferior capsuloligamentous lesion and they form our control
group (group II - CSI)
Figure 1: Flowchart of case selection
Database of 290 patients
who underwent an arthroscopy for the final
diagnosis of any type of SI
6 patients were deceased125 patients could not be
reached72 patients declined to
participate
30 patients because of lack of interest
42 patients due to professional time
restrictions
87 patients were succesfully contacted
29 patients had only isolated anterosuperior
capsuloligamentous lesions (group I - MSI)
58 patients had at least an anteroinferior
capsuloligamentous lesion (group II - CSI)
7
The clinical history, clinical presentation, professional and sport activities as well as
postoperative rehabilitation were evaluated based on the medical files and a self-defined
questionnaire. This questionnaire included questions about the onset of symptoms, the
clinical symptoms, pre- and postoperative professional and sport activities, return to work
and sport, and duration of postoperative rehabilitation. The ROM investigated in this study is
the subjective ROM. This information is only part of the questionnaire since there was no
final clinical examination and insufficient data was available in the medical files. The Oxford
Shoulder Instability Score (OSIS) and the Western Ontario Shoulder Instability index (WOSI)
were used to assess the shoulder function at a final review at time of the study at a mean of
83 months (range 12 months to 240 months) postoperatively. We used the OSIS edition
where the scores of 12 and 60 represent respectively the best and worst scores. In the
edition we used for WOSI a score of 0 (100%) represents the best and 2100 (0%) the worst
score.
Data was analyzed with the use of SPSS Statistics 22 of IBM. Means and crosstables were
performed. Possible significance was reviewed by using the chi-square test and the
independent samples T-test. For all tests a threshold of significance of 0,05 was used.
8
Results.
Patient demographics (table 1) showed that the mean age at time of surgery was
significantly higher in group I (p=0,001). Although the percentage of women in group I was
higher than in group II, the difference was not significant. The dominant arm was affected
more frequently than the non-dominant arm and this was similar in both groups.
Group I Group II
Mean age at time of surgery 36,62 ± 10,48 years
(range 16-56)
28,84 ± 9,41 years
(range 16-60 )
Gender
Female
Male
15 (51,7%)
14 (48,3%)
23 (39,7%)
35 (60,3%)
Affected arm
Dominant arm
Non-dominant arm
21 (72,4%)
8 (27,6%)
38 (65,5%)
20 (34,5%)
Table 1: Patient demographics
At the time of the onset of the symptoms the proportion of the type of work was almost
similar in both groups (figure 2). More than 80% of the patients in both groups had either a
manual or an administrative work. A small portion of patients was either still student or
housewife (without any other professional activity).
Figure 2: Type of work prior to surgery
48,3%
(n: 14)43,1%
(n: 25)
34,5%
(n: 10) 37,9%
(n: 22)
6,9% (n: 2)1,7% (n: 1)
10,3%
(n: 3) 17,2%
(n: 10)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
group I group II
Type of work
student
housewife
administrative work
manual work
9
The majority of patients in both groups practiced an overhead sport (swimming, volleyball,
tennis, basketball, fitness or American football) at the time of the onset of the symptoms
(figure 3). About a fifth of the patients in group I and about a third of the patients in group II
practiced another sport (running, soccer, cycling) and the remaining patients did not practice
a sport. More patients in group II than in group I practiced a sport.
Figure 3: Type of sport prior to surgery
For the majority of the patients in both groups the pain at rest disappeared less than 6
months after the surgery (table 2). But if the pain persisted it was more likely that the pain
remained for more than 12 months for patients in group I while the pain disappeared in
most cases within the year for patients in group II.
Pain at rest Group I Group II
Gone after < 6 months 20 (69,0%) 41 (70,7%)
Gone after 6-12 months 2 (6,9%) 12 (20,7%)
Gone after > 12 months 7 (24,1%) 5 (8,6%)
Table 2: Pain at rest
For more than 50% of the patients in both groups night pain disappeared within 6 months
after the surgery (table 3). The pain remained however for more than 12 months in
approximately a third of the patients in group I.
62,1%
(n: 18)
62,1%
(n: 36)
20,7%
(n: 6)
32,7%
(n: 19)
17,2%
(n: 5)
5,2% (n: 3)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
group I group II
Type of sport
no sport
another sport
overhead sport
10
Night pain Group I Group II
Gone after < 6 months 15 (51,7%) 36 (62,1%)
Gone after 6-12 months 4 (13,8%) 14 (24,1%)
Gone after > 12 months 10 (34,5%) 8 (13,8%)
Table 3: Night pain
In 80% of the patients in group II the pain during overhead activities was gone in less than 12
months while this was the case in less than 60% of the patients in group I (table 4). A
significant relationship between our study groups and the time it takes before the pain
during overhead activities disappears (p=0,036) was found.
Pain during overhead activities Group I Group II
Gone after < 6 months 11 (37,9%) 25 (43,1%)
Gone after 6-12 months 6 (20,7%) 23 (39,7%)
Gone after > 12 months 12 (41,4%) 10 (17,2%)
Table 4: Pain during overhead activities
The mean OSIS was significantly (p=0,034) lower in group II than in group I. The mean WOSI
was also lower in group II than in group I (table 5). This means that patients in group I have a
worse outcome than patients in group II. Initially, the pain at rest, the night pain and the
pain during overhead activities disappeared during the postoperative rehabilitation but at a
certain point of time in the follow-up the pain returned for respectively 10, 14 and 14
patients. Sensation of pain was one of the topics inquired in both scores which means that it
has a negative influence on the scores.
Group I Group II
OSIS
Mean 30,86 ± 13,38 24,76 ± 11,96
Median 30 21
WOSI
Mean 910,34 ± 575,93 (56,7%) 692,02 ± 515,66 (67,0%)
Median 848 (59,6%) 618 (70,6%)
Table 5: OSIS and WOSI
11
More than 40% of the patients in group I and more than 50% of the patients in group II
returned to their normal subjective ROM in less than 6 months (table 6). More patients in
group I however remain to have a limitation of their subjective ROM for more than 12
months.
Return to normal subjective ROM Group I Group II
After < 6 months 12 (41,4%) 32 (55,2%)
After 6-12 months 7 (24,1%) 11 (18,9%)
After > 12 months 10 (34,5%) 15 (25,9%)
Table 6: Return to normal subjective ROM
Less than 20% of the patients in both groups were unable to return to the same work as
before the surgery (figure 4). In group II all patients who were able to return to the same
work were able to do so within 12 months and most of them even in less than 6 months.
This pronounced trend was not established for group I. In contrast to the patients in group II,
almost 14% of the patients in group I needed more than 12 months to return to their same
work. Overall, we clearly see that patients in group I returned slower to their same
professional activities (p=0,015).
Figure 4: Return to the same work
Tables 7 and 8 show the possible differences for both groups between the patients who
were able to return to their same work after surgery and those who were unable to do so.
Almost all patients who were unable to return to their same work found a different or a
customized job after a period of more than 12 months. In both groups the mean OSIS and
55,2%
(n: 16)
75,9%
(n: 44)
17,2%
(n: 5)
6,9% (n: 4)13,8%
(n: 4)
13,8%
(n: 4)17,2%
(n: 10)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
group I group II
Return to the same work
no return to the same work
> 12 months
6-12 months
< 6 months
12
WOSI was significantly worse for the patients who were not able to return to their same
work (p=0,000). All patients in group II and 75% of the patients in group I who were unable
to return to the same work were manual workers. A significant relationship was established
for group II (p=0,001). We noticed that only the type of work, namely manual work, is a
determining factor in order to be able to resume the same work after surgery. No great
differences were found for the other variables.
Group I: patients able to
return to the same work
after surgery (n=25)
Group I: patients unable to
return to the same work
after surgery (n=4)
Mean age at time of the
surgery 36,56 ± 11,02 37,00 ± 7,39
Gender (f/m) 13/12 2/2
Dominant arm 19 (76,0%) 2 (50,0%)
Type work
Manual work 11 (44,0%) 3 (75,0%)
Administrative work 10 (40,0%) 0 (0 %)
Housewife 1 (4,0%) 1 (25,0%)
Student 3 (12,0%) 0 (0 %)
OSIS
Mean 27,88 ± 11,83 49,50 ±3,70
Median 27 51
WOSI
Mean 786,32 ± 515,24 (62,6%) 1685,50 ± 206,52 (19,7%)
Median 773 (63,2%) 1688 (19,6%) Table 7: Group I – ability to return to the same work
Group II: patients able to
return to the same work
after surgery (n=48)
Group II: patients unable
to return to the same work
after surgery (n=10)
Mean age at time of the
surgery 28,69 ± 9,97 29,6 ± 6,42
Gender (f/m) 21/27 2/8
Dominant arm 32 (66,7%) 6 (60,0%)
Type work
Manual work 15 (31,3%) 10 (100 %)
Administrative work 22 (45,8%) 0 (0 %)
Housewife 1 (2,1%) 0 (0 %)
Student 10 (20,8%) 0 (0 %)
OSIS
Mean 21,54 ± 9,06 40,20 ± 12,51
Median 20 42
WOSI
Mean 556,75 ± 390,40(73,5%) 1341,30 ±567,56 (36,1%)
Median 528 (74,9%) 1467 (30,1%) Table 8: Group II – ability to return to the same work
13
Almost a third of the patients in group I and a fifth of the patients in group II who practiced a
sport before surgery stopped with their sport after surgery (figure 5). All the other patients
returned to their primary sport. Two times as many patients in group II than in group I were
able to do so in less than 6 months. Approximately 40% of the patients in both groups were
capable to return to their same level of sport in less than 12 months. More than a quarter of
all patients in both groups returned to their same sport after more than 12 months but in
group II more patients were unable to do so at the same level. Some patients in group II
could not remember when they resumed the same level of their sport and the data was also
not reflected in their medical files. Overall, patients in group II seemed to be able to return
sooner to their same level of sport than patients in group I.
Figure 5: Return to the same level of sport
Similar as for the return to the same work tables 9 and 10 show the possible differences for
both groups between the patients who were able to return to their same sport after surgery
and those who were unable to do so. In both groups, the patients unable to return to their
same sport scored worse on both mean OSIS and WOSI. The same percentage of patients in
both groups who practiced an overhead sport were unable to resume their sport (namely 4
out of the 18 patients in group I and 8 of the 36 patients in group II or 22% in both groups).
12,5% (n: 3)
25,5%
(n: 14)
29,2%
(n: 7)
18,2%
(n: 10)
16,7%
(n: 4) 5,5% (n: 3)
12,5% (n: 3) 21,8%
(n: 12)
9,1% (n: 5)
29,2%
(n: 7)
20,0%
(n: 11)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
group I group II
Return to the same level of sport
never returned to the same sport
no data of time to return to the same level of
sport
> 12 months, but at a lower level of the same
sport
> 12 months
6-12 months
< 6 months
14
Group I: patients able to
return to the same sport
after surgery (n=17)
Group I: patients unable
to return to the same
sport after surgery (n=7)
Mean age at time of the
surgery
36,71 ± 11,74 36,57 ± 11,75
Gender (f/m) 9/8 3/4
Dominant arm 12 (70,6%) 6 (85,7%)
Type work
Manual work 7 (41,2%) 5 (71,4%)
Administrative work 7 (41,2%) 1 (14,3%)
Housewife 1 (5,9%) 0
Student 2 (11,8%) 1 (14,3%)
Type sport
Overhead sport 14 (82,4%) 4 (57,1%)
Other sport 3 (17,6%) 3 (42,9%)
OSIS
Mean 25,94 ±12,59 36,43 ±13,82
Median 23 42
WOSI
Mean 767,76 ± 612,00 (63,4%) 1019,00 ±464,46 (51,5%)
Median 476 (77,3%) 1016 (51,6%) Table 9: Group I – ability to return to the same sport
Group II: patients able to
return to the same sport
after surgery (n=44)
Group II: patients unable
to return to the same
sport after surgery (n=11)
Mean age at time of the
surgery
28,23 ± 8,90 29,18 ± 8,93
Gender (f/m) 20/24 2/9
Dominant arm 32 (72,7%) 4 (36,4%)
Type work
Manual work 18 (40,9%) 6 (54,5%)
Administrative work 18 (40,9%) 4 (36,4%)
Housewife 0 0
Student 8 (18,2%) 1 (9,1%)
Type sport
Overhead sport 28 (63,6%) 8 (72,7%)
Other sport 16 (36,4%) 3 (27,3%)
OSIS
Mean 24,55 ± 11,92 26,27 ± 12,72
Median 21 22
WOSI
Mean 666,82 ±519,68 (68,2%) 806,55 ±536,93 (61,6%)
Median 618 (70,6%) 697 (66,8%) Table 10: Group II – ability to return to the same sport
15
Discussion.
MSI patients have a slower postoperative rehabilitation course, a slower return to work and
sport, and a worse outcome than the CSI patients which confirms our hypothesis.
The mean age at time of surgery was significantly higher (p=0.001) in group I than in group II.
This data of our group I was conform with the 38,3 ± 6,8 years (range 18-59) in the study of
Garofalo et al.. In the study of Nordenson et al. the mean age at time of surgery was lower,
namely 22,5 ± 7,3 years (range: 16-36). One possible reason for this may be that their study
group consisted only of patients with MSI who presented themselves with a subacromial
impingement syndrome.
The female-male ratio and the dominance of the affected arm in our study group was similar
with the data in the studies of Nordenson et al. (female/male-ratio: 10/11; dominant arm:
70%) and Garofalo et al. (female/male-ratio: 12/11; dominant arm: 65,2%). Castagna et al.
noted in his study that MSI generally occurs in the dominant arm.
The 3 types of pain we studied (namely pain at rest, night pain and pain during overhead
activities) disappeared slower in group I than in group II. In both our groups we noticed a
trend that first of all the pain at rest disappears, then the night pain and finally the pain
during overhead activities.
Based on the mean OSIS and WOSI we see that patients in group I have a worse outcome
than patients in group II. However, we must hereby note that the scores are relatively low in
both groups. This can be explained by the fact that the scores of the patients who were not
able to return to their same work or same sport were much worse than the scores of the
patients who were able to do so. There was also a large range of follow-up at the moment
the scores were administrated.
Similar as we noticed for pain, we observed a trend of a slower return to normal subjective
ROM in the patients in group I than those in group II. This tendency was however much less
pronounced than the trend observed for pain. Due to the fact that we did not have enough
data of the specific tests we could not study the observation of Castagna et al. that MSI
patients have a permanent restriction in external rotation of a few degrees.
Notwithstanding the fact that the type of work was similar in both groups, the patients in
group I returned slower to their work. This result can be explained by the fact that they have
a longer postoperative rehabilitation. We cannot compare our results of the MSI patients in
group I with respect to work with other studies since the studies of Nordenson et al. and
Garofalo et al. did not describe results concerning work. Castagna et al. noted however that
AIOS occurs most frequently in overhead athletes or in heavy “overhead young workers”.
16
In group II we established a significant relationship between type of work before surgery and
the ability to return to the same profession after surgery (p=0,001). Type of work before
surgery can possibly be an explanation on why some patients are unable to return to their
same profession. Only manual workers have a risk not to be able to return to their same
professional activity as before surgery. We see that patients who are unable to return to the
same work score significantly worse on both the OSIS and WOSI.
More patients in group II were active in sports than in group I. The percentage of athletic
patients in our group I was higher than the percentage in the study of Nordenson et al.
(75%). These findings confirm that MSI can occur both in athletic and non-athletic persons as
stated by Castagna et al. The results of Nordenson et al. and this study suggest however that
there is a tendency that MSI occurs more in athletic than in non-athletic persons. In both our
groups around two third of the patients practiced an overhead sport. This percentage of
patients who practiced an overhead sport is quite comparable with the 70% of the patients
in the study of Nordenson et al. and our data confirms the statement of Castagna et al.
Just as the return to the same work, patients in group I returned slower to their same level
of sport than the patients in group II. This can, same as for the return to work, be explained
by the fact that they have a longer postoperative rehabilitation. These results are
comparable with other studies. Patients after a Bankart repair can return on average after 6
to 9 months after the repair surgery to their sport while this is rather 12 months for patients
with SLAP lesions.24, 25, 26
No explanation was found for the fact why some patients are unable to return to their same
sport since among the patients who were unable to return to their same sport some of them
practiced overhead sports and some of them other sports. They scored also lower on both
outcome measures.
Our study has several limitations because of its retrospective character and its relatively
small study group. The great range of the follow-up is also a limitation. A strength of our
study is that both groups were operated by only 2 experienced shoulder surgeons. Our study
group is also larger than the study population in the studies of Garofalo et al. (23 patients)
and Nordenson et al. (20 patients) which are to date practically the only studies that
conducted research for MSI. Another important strength is that we compare both types of SI
in 1 study which was not yet established until now.
A suggestion for further research can be to investigate more shoulder related variables (like
time between the onset of symptoms and the diagnosis/surgery, the characteristics of the
clinical symptoms, etc.) in order to find possible determining factors that influence the
ability to return to the same work and sport.
17
Conclusion.
MSI is a relatively new concept and there exist not many studies that already investigated
the specific pattern of MSI. By means of this study, we tried to reveal the differences
between MSI and CSI and this for the postoperative rehabilitation, return to work and sport,
and the outcome. We can conclude that patients with MSI have a slower postoperative
rehabilitation course and they also return slower to work and sport than the CSI patients.
Furthermore the MSI patients have a worse outcome compared to the CSI patients.
18
References.
1. Castagna A., Nordenson U., Garofalo R. en Karlsson J. Minor shoulder instability. The
journal of arthroscopic and related surgery 2007; 23; 211-215.
2. Nordenson U., Garofalo R., Conti M., Linger E., Classon J., Karlsson J. en Castagna A. Minor
or occult shoulder instability: an intra-articular pathology presenting with an extra-articular
subacromial impingement symptoms. Knee Surg Sports Traumatol Arthrosc 2011; 19; 1570-
1575.
3. Garofalo R.,Pouliart N., Vinci E., Franceshi G., Aldegheri R. en Castagna A. Anterosuperior
labral tear without biceps anchor involvement: a subtle isolated cause of a painful shoulder.
The journal of artroscopic and related surgery 2011; 27; 17-23.
4. Kanatli U., Ozturk Y.B. en Bolukbasi S. Anatomical variations of the anterosuperior labrum:
prevalence and association with type II superior labrum anterior-posterior (SLAP) lesions.
Journal of shoulder and elbow surgery 2010; 19; 1199-1203.
5. Terry C.G., Chopp M.T. Functional anatomy of the shoulder. Journal of athletic training
2000; 35; 248-255.
6. Haarman H.J.Th.M., Rommens P.M., Goris R.J.A., Klasen H.J. en Patka P. Klinische
traumatologie. Nederland, Reed business, 2000.
7. Schuenke M., Anatomische atlas Promotheus - Algemene anatomie en
bewegingsapparaat, Nederland, Bohn Stafleu van Loghum, 2010.
8. Tischer T., Vogt S., Kreuz P. and Imhoff A. Arthroscopic anatomy, variants and pathologic
findings in shoulder instability. The journal of arthroscopic and related surgery 2011; 27;
1434-1443.
9. Hunt S.A., Kwon Y.W., Zuckerman J.D. The rotator interval: anatomy, pathology and
strategies for treatment. J Am Acad Orthop Surg 2007; 15; 218–227.
10. Ackland D.C., Pandy M.G. Lines of action and stabilizing potential of the shoulder
musculature. J Anat 2009; 215; 184–197.
11. Williams MM., Snyder SJ., Buford D. Jr. The Buford complex – the “cord-like” middle
glenohumeraal ligament and absent anterosuperior labrum complex: A normal anatomic
capsulolabral variant. Arthroscopy 1994; 10 ; 241–247.
12. Ilahi O.A., Labbe M.R., Cosculluela P. Variants of the anterosuperior glenoid labrum and
associated pathology. Arthroscopy 2002; 18; 882–886.
19
13. Ilahi O.A., Labbe M.R., Cosculluela P. Variants of the anterosuperior glenoid labrum and
associated pathology. Arthroscopy 2002; 18; 882–886.
14. Huber W.P., Putz R.V. Periarticular fiber system of the shoulder joint. Arthroscopy 1997;
13; 680–691.
15. Porcellini G., Paladini P., Campi F., Paganelli M. Shoulder instability and related rotator
cuff tears: arthroscopic findings and treatment in patients aged 40 to 60 years. Arthroscopy
2006; 22; 270–276.
16. Healey J.H., Barton S., Noble P., Kohl III H.W., Ilahi O.A. Biomechanical evaluation of the
origin of the long head of the biceps tendon. Arthroscopy 2001; 17; 378–382.
17. Werner A., Mueller T., Boehm D., Gohlke F. The stabilizing sling for the long head of the
biceps tendon in the rotator cuff interval: A histoanatomic study. Am J Sports Med 2000; 28;
28–31.
18. Lewis A., Kitamura T., Bayley J.I.L. The classification of shoulder instability: new light
through old windows. Current Orthopaedics 2004; 18; 97–108.
19. Snyder S.J., Karzel R.P., Del Pizzo W., Ferkel R.D., Friedman M.J. SLAP lesions of the
shoulder. Arthroscopy 1990; 6; 274-279.
20. Ilahi O.A., Labbe M.R., Cosculluela P. Variants of the anterosuperior glenoid labrum and
associated pathology. Arthroscopy 2002; 18; 882-886.
21. Pouliart N., Somers K., Gagey O. Arthroscopic glenohumeral folds and microscopic
glenohumeral ligaments: the fasciculus obliquus is the missing link. J Shoulder Elbow Surg
2008; 17; 418-430.
22. Pouliart N., Somers K., Eid S., Gagey O. Variations in the superior capsuloligamentous
complex and description of a new ligament. J Shoulder Elbow Surg 2007; 16; 821-836.
23. Pouliart N., Gagey O. The arthroscopic view of the glenohumeral ligaments compared
with anatomy: Fold or fact? J Shoulder Elbow Surg 2005; 14; 324-328.
24. Pavlik A., Csépai D., Hidas P., Bánóczy A. Sports ability after Bankart procedure in
professional athletes. Knee Surg Sports Traumatol Arthrosc. 1996; 4; 116-120.
25. McDermott D.M., Neumann L., Frostick S.P., Wallace W.A. Early results of Bankart repair
with a patient-controlled rehabilitation program. J Shoulder Elbow Surg. 1999; 8; 146-150.
26. Neuman B.J., Boisvert C.B., Reiter B., Lawson K., Ciccotti M.G., Cohen S.B. Results of
arthroscopic repair of type II superior labral anterior posterior lesions in overhead athletes:
assessment of return to preinjury playing level and satisfaction. Am J Sports Med. 2011; 39;
1883-1888.
20
Appendix
Background information on shoulder anatomy.
Shoulder instability (SI) is a very frequent pathology of the shoulder. The glenohumeral joint
is the most often dislocated joint in the body due to the combination of a large range of
motion (ROM) and an insufficient bony stabilization. As result of this discrepancy the
shoulder needs an important stabilization mechanism. 7
The glenohumeral joint is a ball and socket joint and is well suited for the extreme mobility
due to the mismatch between the big head of the humerus (20-24 cm²) and the small
glenoid fossa (6-7cm²). The cavital glenoidalis only makes contact with a third or fourth of
the caput humeralis.6, 7, 8
This contact area is increased by the labrum glenoidalis (cfr. infra).
Despite this lack of articulating covering, the normal shoulder precisely constrains the head
of the humerus to within 1 to 2 mm of the center of the glenoid cavity throughout most of
the arc of motion. This specific limitation of the center of rotation through the large arc of
motion is the result of an interaction between different stabilizers.5
The stability of the shoulder is provided by a complex and delicate interaction between
various stabilization mechanisms that can be classified in both static as well as dynamic
stabilizers.8 The labrum, the joint capsule and the ligaments are considered to be the static
stabilizers while the rotatorcuff, the deltoid muscle, the biceps muscle and the scapular
muscles are considered to be the dynamic stabilizers.5
The labrum consists of a fibrous peripheral layer and a fibro-cartilaginous transit zone.4, 5
The
blood supply is minimal in the superior and anterosuperior part of the labrum which may
lead to a limited regeneration potential in these regions.8
The labrum is one of the most important stabilizers and is very well studied in the literature.
It has 3 functions.4 Firstly, the labrum increases the stability and this by two mechanisms.
The first mechanism is that the labrum expands the articular surfaces (increase of a third) as
the result of its localization to the glenoid rim, what leads to a larger contact surface. The
second mechanism is that the labrum deepens the concavity of the glenoid cavity in the
superoinferior and anteroposterior faces with an average of respectively 9mm and 5mm.8 A
disruption of the labrum will lead to a reduction of no less than 20% of the resistance to
translation.5 Secondly, the labrum has a neutralizing effect on the stress distribution.
4, 8 A
disruption of the labrum will also lead to overstressed areas.4 Thirdly, the labrum acts as an
anchor point for the capsuloligamentous structures and the long head of the biceps muscle.4,
5, 8 Bankart was of the opinion that the detachment of the anteroinferior glenoid rim was the
essential injury responsible for the high incidence of the recurrent anterior dislocations.5
21
The anterosuperior part of the labrum has various anatomical variations like the superior
sublabral recess, the sublabral foramen and the Buford complex.4, 5, 8
The superior sublabral
recess is a recess that is located at the 12 o’clock position below the anchor of the long head
of the biceps muscle and the anterosuperior rim of the labrum.4 The sublabral foramen is a
groove which is located at the 2 o’clock position between the normal anterosuperior labrum
and the anterior cartilaginous edge of the glenoid.4 In the literature a prevalence of 11,9 to
18,3% has been described for this variant.11, 20
The Buford complex is a third variety that is
characterized by a thick, cordlike middle glenohumeral ligament (MGHL) that attaches at the
superior part of the labrum to the base of the tendon of the biceps, in combination with the
absence of the anterosuperior labrum.4 This variant has a prevalence of 1,5 to 7,5%.
11, 20 It is
sometimes a challenge for the surgeon to distinguish between anatomical variations and
pathological conditions.8 Although it is not clear in the literature, it is likely that there is a
causal relationship between the anatomical variations and superior labral lesions.4
The joint capsule consists of a complex of circular and radially arranged collagen fibers and is
reinforced by multiple reinforcements like the coracohumeral ligament, the superior
glenohumeral ligament (SGHL), the MGHL, the inferior glenohumeral ligament (IGHL) and
the insertion of the rotatorcuff.8 The joint capsule and the different glenohumeral ligaments
are anatomically closely adherent in spite of the fact that they are usually described
separately in the literature. The surface of the joint capsule is about 2 times the surface of
the head of the humerus and allows thereby a large ROM.5
The four most important ligaments for SI are the coracohumeral ligament, the SGHL, the
MGHL and the IGHL.8
The coracohumeral ligament and the SGHL run parallel and have the same function.
Together they form the rotator interval (RI).5, 8, 17, 22
The RI is the space between the anterior
rim of the supraspinatus muscle and the superior rim of the subscapularis muscle. The
tension of the RI is influenced by the coracohumeral ligament, the SGHL and the joint
capsule in between.9 A wide RI can play an important role in inferior, anterior and posterior
instability.8 In addition the coracohumeral ligament and the SGHL are also the major
components of the biceps reflection sling (the pulley system).10, 17
The MGHL is the most variable ligament of the 3 glenohumeral ligaments and is absent in 8
to 30% of the patients.5, 8, 11
The MGHL may occur like a cordlike ligament and this
anatomical variant can be seen as a protective factor against SI.12, 13
The MGHL can also
appear as a thin cover or can even be absent. These 2 conditions are more common in
patients with anteroinferior SI so they can be considered as a predisposing factor.8, 12, 13
The IGHL is the thickest and most consistent ligament of the 3 glenohumeral ligaments and is
often described as a complex of an anterior band, an axillary pouch and a posterior band.5, 8
The rotatorcuff is a group of muscles consisting of the supraspinatus muscle, the
infraspinatus muscle, the teres minor muscle and the subscapularis muscle and acts as a
22
dynamic control mechanism of the head of the humerus.5 The rotatorcuff is very important
for the shoulder stability and tears of the rotatorcuff and glenohumeral instability are
related to each other.15
Rotatorcuff activation results in humeral head rotation and
depression in positions of abduction.5
The long head of the biceps muscle runs intra-articular and consists of two different types of
fibers.5 The biomechanically important fibers insert on the supraglenoid tubercle while the
remaining fibers insert variable on the labrum and have essentially a forming function.16
Pathological lesions of the long head of the biceps muscle can lead to Superior Labral
Anterior Posterior (SLAP)-lesions.8
The deltoid muscle has also a stabilizing effect on the glenohumeral joint due to its
contraction which results in a relative compression on the articular surfaces. This stabilizing
effect increases when the shoulder becomes instable.