The Journal of Bone and Joint Surgery (American). 2005;87:419-432.
doi:10.2106/JBJS.D.01921
© 2005 The Journal of Bone and Joint Surgery, Inc.
Open Operative Treatment for Anterior Shoulder Instability: When and Why?
Peter J. Millett, MD, MSc1,
Philippe Clavert, MD2 and
Jon J.P. Warner, MD3
1 Harvard Shoulder Service, Brigham and Women's Hospital, 75 Francis Street,
Boston, MA 02115. E-mail address:
pmillett{at}partners.org
2 Department of Orthopaedic Surgery, Hautepierre University Hospital, Avenue
Moliere, 67098 Strasbourg CEDEX, France
3 Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114
The authors did not receive grants or outside funding in support of their
research or preparation of this manuscript. They did not receive payments or
other benefits or a commitment or agreement to provide such benefits from a
commercial entity. No commercial entity paid or directed, or agreed to pay or
direct, any benefits to any research fund, foundation, educational
institution, or other charitable or nonprofit organization with which the
authors are affiliated or associated.
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Abstract
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The treatment of anterior glenohumeral instability continues to evolve.
Open capsulolabral repairs are time-tested and reliable.
In an era in which arthroscopic techniques continue to improve, open
surgery remains an acceptable option, and there are still certain injury
patterns that cannot be adequately addressed arthroscopically.
Decision-making regarding surgery for instability is influenced by the
surgeon's experience and the relevant pathological findings.
Open operative treatment is the preferred approach in many instances of
recurrent anterior instability, particularly when there is bone and
soft-tissue loss and in revision settings.
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Introduction
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Open surgical treatment for primary anterior glenohumeral instability is
reliable and time-tested and can yield excellent clinical
results1-4.
With advancements in arthroscopic technique, there has been a growing trend
toward arthroscopic treatment of anterior shoulder instability. In many
instances, arthroscopic treatment is preferred by patients and surgeons
because it is minimally invasive, obviating the need for releasing and
repairing the subscapularis; because it allows better identification and
treatment of associated pathological conditions; and because it decreases
morbidity and facilitates an outpatient approach. Furthermore, recent studies
have demonstrated that the results of arthroscopic treatment of recurrent
traumatic anterior instability are comparable with those achieved historically
with open
procedures5-8.
Despite these exciting advances, open surgery remains an acceptable method
of treatment, particularly when a surgeon lacks the equipment, experience, or
technical expertise needed to perform an arthroscopic repair. Furthermore,
open surgery remains the preferred method of treatment in situations where
even the most modern arthroscopic techniques cannot adequately address the
pathoanatomy, such as anterior instability in the setting of large bone
defects or soft-tissue deficiencies. We will review the indications,
techniques, and complications of open surgical treatment of anterior shoulder
instability, summarizing the various types of open stabilization procedures
and their clinical results and highlighting the specific situations in which
open surgery remains the preferred method of treatment.
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Open Surgical Techniques
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There are two basic types of surgical approaches for shoulders with
anterior instability: "anatomic" and "non-anatomic"
repairs. With anatomic repairs, the goals are to restore the labrum to its
normal position and to reestablish the appropriate tension in the shoulder
capsule and ligaments. Depending on the pathoanatomy encountered, anatomic
repairs were historically accomplished either with the classic Bankart
procedure that was popularized by Rowe or with the capsular shift procedure
that was popularized by
Neer1-3,9-15.
Currently, most open procedures involve a combination of these approaches,
with a Bankart repair performed in conjunction with a capsular shift, and the
tension of the capsule is determined selectively. The importance of this
combined approach to the capsule and labrum was highlighted by the
biomechanical study of a cadaver model by Speer et al., who found that
complete dislocation could not occur after the creation of a Bankart lesion
unless there was associated injury to the
capsule16.
The goal of non-anatomic surgical procedures is to stabilize the shoulder
by compensating for the capsulolabral and osseous injury with an osseous or
soft-tissue checkrein that blocks excessive translation and restores
stability. Examples of non-anatomic types of stabilizations include the
Bristow and Latarjet procedures, which are transfers of the coracoid to the
glenoid17,18;
the Magnuson-Stack
procedure19, which
is an advancement of the subscapularis that was popularized by DePalma; and
the Putti-Platt procedure, which is an imbrication and shortening of the
subscapularis20.
Many
studies21-25
have demonstrated excellent outcomes with non-anatomic stabilizations, but the
reported complications, such as loss of motion, recurrent instability, and
premature
arthritis2,19,26-30,
have led many North American surgeons to avoid them as a firstline
approach1,2,31,32.
Furthermore, because the anatomy is distorted by these types of repairs,
revision surgery can be very challenging; however, when these procedures are
performed properly in appropriate situations by skilled surgeons, good results
can be obtained.
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Patient Selection
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Careful preoperative evaluation that includes determination of the
pathoanatomy is critical so that the best method of treatment can be
selected33-36.
The clinician must collect detailed information about the cause of the
instability, the number and frequency of episodes, the degree of trauma
necessary for recurrence, the arm position at the time of the initial injury,
and the arm position that provokes symptoms. Mechanical symptoms, such as
catching or locking, may suggest a displaced labral tear or a large osseous
defect that is engaging. Instability that occurs in the midrange of motion or
that occurs during sleep suggests an osseous defect.
Several important findings of the physical examination should be
highlighted. Passive and active motion should be assessed and compared with
those of the contralateral limb. A substantial side-to-side difference in
abduction suggests injury to the inferior glenohumeral ligament complex.
Strengthtesting is used to evaluate the functions of the rotator cuff.
Weakness in an older patient with a traumatic dislocation suggests a rotator
cuff tear. In the revision setting, a marked increase in passive external
rotation with positive lift-off and belly-press tests confirms failure of the
subscapularis. A detailed neuromuscular assessment should be performed because
axillary nerve injury is not uncommon with traumatic anterior instability.
Although infrequent, suprascapular nerve injuries can also occur, especially
in revision settings. Associated injuries to the superior part of the labrum
(SLAP lesions) are common and can be detected by provocative examination
maneuvers such as the active compression test. In the appropriate clinical
setting, an apprehension sign that is relieved by a relocation maneuver can be
virtually diagnostic of anterior shoulder instability and a Bankart
lesion37. The
anteroposterior laxity of the shoulder should be assessed with load and shift
testing, and the inferior laxity should be assessed with inferior translation
(sulcus testing). A large sulcus sign that recreates symptoms of instability
is pathognomonic for multidirectional instability. Furthermore, a large sulcus
sign in the adducted arm that does not decrease when the arm is placed in
external rotation indicates an insufficiency of the rotator
interval10,38-44.
When marked muscle-guarding confounds the office evaluation, careful
examination with the patient under anesthesia prior to surgery is
essential10,41-44.
Imaging
Orthogonal radiographs of the
shoulder45-47
help one to classify the direction of the instability and to demonstrate
relevant osseous lesions. Anteroposterior and axillary radiographs aid in the
detection of relevant glenoid fractures, Hill-Sachs
lesions45, or
associated fractures of either the anatomic neck or the greater tuberosity. We
prefer a true anteroposterior radiograph of the glenohumeral joint, a West
Point axillary radiograph, and a Stryker notch radiograph for individuals in
whom instability is suspected. The appearance of static anterior subluxation
of the humeral head suggests either disruption of the glenoid or a
subscapularis rupture. A rotator cuff tear should be suspected in patients
with an inferior dislocation.
Advanced imaging can be very helpful for defining the pathoanatomy and for
planning the surgical approach. A magnetic resonance imaging-arthrogram can
confirm a capsulolabral injury, such as a Bankart lesion or a SLAP lesion, and
can be particularly useful for diagnosing rare but important lesions, such as
humeral avulsions of the glenohumeral ligaments or capsular ruptures
(Fig. 1). Because of the
technical difficulty involved in arthroscopic repair of these types of
injuries, it is useful to obtain this information preoperatively so that
adequate patient counseling and surgical planning can be carried out.

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Fig. 1 Arthroscopic photograph of a humeral avulsion of the glenohumeral ligaments
in a right shoulder, viewed from posterior. The humeral head is superior, and
the tear is located at the anteroinferior aspect of the axillary pouch, as is
typical. Because the capsule and ligaments insert beneath the humeral head,
arthroscopic repair is usually not possible.
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When bone deficiency is suspected, a computed tomography-arthrogram with
three-dimensional reconstructions can be helpful (Figs.
2-A and
2-B). This type of study best
demonstrates acute or chronic bone
loss48 and shows
the orientation of the articular surfaces, as the contrast medium outlines the
cartilage of the glenoid and humeral
head49-51.
A magnetic resonance imaging-arthrogram is better suited for demonstrating
soft tissues, although bone deficiencies can still be
detected50-53.

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Fig. 2-B Three-dimensional computed tomography reconstruction highlighting the
amount of anterior bone deficiency. In these settings, arthroscopic repair is
contraindicated and an open bone-grafting procedure is indicated to restore
the glenoid arc and concavity.
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Gerber and
Nyffeler54
demonstrated a method for quantifying the degree of glenoid bone loss by
measuring the glenoid surface on either an oblique sagittal image or a
three-dimensional reconstruction. Through biomechanical testing, they
determined that the force required for anterior dislocation is reduced by 70%,
compared with that required when the glenoid is intact, if the length of the
glenoid defect exceeds its maximum radius. In such cases, standard Bankart
repairs (arthroscopic or open) are likely to fail, and osseous augmentation is
recommended48.
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Indications for Surgery
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In most cases, the essential lesion in a shoulder with traumatic anterior
instability is a Bankart
lesion9, which
usually occurs with some degree of capsular injury or
stretch16. When
this lesion is encountered, either an arthroscopic or an open anatomic
capsulolabral repair should be successful.
Most cases of anterior glenohumeral instability can be treated with either
open or arthroscopic approaches, depending on the experience and expertise of
the surgeon, because there is substantial overlap in the indications for these
procedures. Shoulder arthroscopy requires special technical expertise and
equipment, and the arthroscopic surgery becomes even more demanding as the
instability patterns become more complex. For example, repairing a Bankart
lesion arthroscopically in a young patient with anterior instability is fairly
straightforward, but a revision procedure may be much more difficult to tackle
arthroscopically. Moreover, when a patient has multidirectional instability,
which requires both anterior and posterior capsular imbrication, even a
primary repair can be a challenge for even an experienced arthroscopic
surgeon. If a surgeon has neither the expertise nor the equipment needed for
arthroscopy, open surgery should be performed. A surgeon with experience in
open surgery can achieve excellent results if the appropriate surgery is
performed for the appropriate indication and with an acceptable level of
skill. A good open procedure will always outperform a bad arthroscopic
one.
Despite the advances in shoulder arthroscopy, there are still several
relative contraindications to the procedure. These include humeral avulsions
of the glenohumeral ligaments and capsular ruptures. These two injuries are
extremely difficult to address arthroscopically by all but the most
experienced arthroscopists. Other relative indications for open surgery
include a previous failed arthroscopic or open repair because it is easier to
address the causes of the instability (which may be multiple) with an open
procedure. Another relative indication for an open approach is a prior failed
thermal capsulorrhaphy. In this setting, the surgeon must be prepared to deal
with poor-quality capsulolabral tissue or even the complete capsular
deficiency that can occur with capsular necrosis.
The appropriate treatment of anterior instability in an athlete who engages
in contact sports remains controversial. Some consider shoulder instability in
such an athlete to be a clear indication for open surgery, and excellent
results have been
reported55. Pagnani
and Dome recently reported excellent long-term results in a group of American
football players who had been treated for recurrent traumatic anterior
instability56. No
patient had recurrent dislocation postoperatively, and only two of fifty-eight
had recurrent subluxation. Others believe that, with careful patient
selection, arthroscopic approaches can yield similar results. Burkhart and De
Beer33 reported on
a group of 194 patients who had undergone an arthroscopic Bankart repair of
the shoulder. One hundred and one of those patients were athletes who
participated in contact sports. While the recurrence rate was 87% in patients
with marked bone defects, it was only 6.5% in those who did not have bone
defects.
There are some absolute indications for an open approach. These include
substantial glenoid or humeral bone loss, capsular deficiency, or irreparable
rotator cuff deficiencies, particularly those of the subscapularis. An osseous
reconstruction should be performed in individuals with major anterior glenoid
erosion. In the rare case in which a large humeral head defect (a Hill-Sachs
lesion) plays a role in the recurrence of instability, open surgery should be
performed. More commonly, however, anterior glenoid bone deficiency plays a
role when there is a large Hill-Sachs defect and instability. When there is a
chronic disruption of the subscapularis, usually in the setting of prior
surgery, an open repair is indicated.
Open repair may not be effective for the treatment of instability in
patients with concomitant severe arthritis. Depending on the status of the
glenoid and surrounding rotator cuff, arthroplasty or arthrodesis may be
better options. Paralysis may also be associated with chronic instability, and
in such cases arthrodesis may be more successful in eliminating
pain57-60.
Absolute contraindications to open repair for the treatment of anterior
instability include voluntary or psychogenic
instability61-63
and active infection.
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Anatomic Repairs
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Open Bankart repairs and capsular shift procedures have been used for many
years, with various modifications, and excellent results have been
reported1,3,11,64.
With appropriate patient selection and careful surgical technique, they yield
excellent success rates. In their classic article, Rowe et al. reported five
recurrences in a series of 145 shoulders (a 3.5% recurrence
rate)3. Gill et
al.1 reported a 95%
success rate, with three recurrences in a series of sixty shoulders, at a mean
of 11.9 years postoperatively. Studies such as these support the assertion
that this technique is the "gold standard." The Bankart procedure
restores normal anatomy by reattaching the labrum to its anatomic position at
the anterior articular margin of the
joint9,65.
The concept of a selective capsular shift was introduced as a refinement of
this technique (Fig. 3). The
selective shift is based on the observation that the capsuloligamentous static
stabilizers function at predictable positions of rotation and act as
checkreins against excessive rotation and
translation11,66
and that the pathoanatomy involves injury to both the labrum and the
capsule16. The
Bankart lesion is anatomically repaired, and then the capsule is shifted to
tighten the joint with avoidance of overconstraint.

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Fig. 3 Illustrations demonstrating the concept of a selective capsular shift. The
Bankart lesion is repaired anatomically, the arm is then placed in the desired
position (approximately 30° of glenohumeral abduction and 30° of
external rotation), and the capsule is shifted laterally to the humerus to
remove redundancy. (Reprinted, with permission, from:
Warner JJ, Johnson D, Miller M,
Caborn DN. Technique for selecting capsular tightness in repair of
anterior-inferior shoulder instability. J Shoulder Elbow Surg.1995
;4:352
-64.[CrossRef][Medline])
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Glenoid Bone Deficiency
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Osteoarticular pathology is rarely a cause of recurrent anterior
instability, but when it is present it is easily missed. Bone deficiency is
also more likely to be a relevant factor in patients who present for revision
surgery. In a small percentage of individuals, developmental glenoid
dysplasia, in which the glenoid is flat or less concave than normal, may
predispose to instability. This is more commonly associated with recurrent
posterior instability, with which a dysplastic, retroverted glenoid may be
present. Morrey and
Janes67 believed
that loss of glenoid bone accounted for <2% of all cases of anterior
instability requiring surgical repair. Marked loss of the glenoid articular
surface as a result of a fracture or erosion occurs more commonly after
traumatic dislocations or recurrent episodes of instability (Figs.
2-A and
2-B). The anterior glenoid rim
can actually become rounded and flattened from recurrent
dislocations68.
Experience has shown that, when such defects are present, there is an
increased risk of failure when only soft-tissue repairs are
performed54,69-71.
Indeed, Burkhart et
al.33,72
observed that, when substantial glenoid erosion (which they described as an
"inverted pear"-shaped glenoid) was identified at arthroscopy in
athletes who participated in contact and collision sports, the failure rate of
arthroscopic capsulolabral repair was >80%. Burkhart et al. evaluated 194
patients who had undergone arthroscopic Bankart repair of the shoulder and
found the recurrence rate to be 4% in 173 patients without bone defects and
67% in those with substantial bone
defects33.
Until recently, there was little recognition of this potentially important
risk factor for failure. Assessment of bone loss was usually anecdotal and
carried out at the time of open or arthroscopic surgery, with descriptions of
mild, moderate, or severe. There are scant quantitative data on what
constitutes important glenoid bone loss and even less on what constitutes
important humeral bone loss. Rowe and
Sakellarides73
believed that up to 30% of the glenoid can be absent without concern about an
increased risk of failure of an open Bankart repair. However, in practice, it
may be very difficult to quantify the exact degree of glenoid loss, even with
direct inspection. This is particularly evident in chronic cases of glenoid
erosion since there is no reference point, as a portion of the glenoid is
already absent. More recent experimental observations have provided
quantitative methods for assessing glenoid bone loss prior to
surgery54,68,69.
When a soft-tissue Bankart repair was performed experimentally in the setting
of glenoid bone loss, the force required for dislocation remained
low54. It seems
likely, therefore, that a similar soft-tissue repair in a patient with such a
lesion will fail unless the bone loss is addressed. A matched ball-in-socket
congruity is essential for the stabilizing concavity-compression effect to
occur70.
Most surgeons now recognize the need to reconstruct or compensate for
anterior glenoid bone
loss54,69,72,74.
The surgical options include either an intra-articular reconstruction with
bone graft or a coracoid process transfer such as the Bristow or Latarjet
procedure. Modern arthroscopic techniques cannot currently address marked
glenoid bone loss. We have formed a framework with which to consider glenoid
bone-grafting on the basis of the patient's symptoms and the biomechanical
findings of Gerber and
Nyffeler54. If the
patient has recurrent instability, particularly with midrange symptoms or
symptoms of instability in their sleep or with decreasing degrees of trauma;
if a bone defect is seen on radiographs; or if a prior arthroscopic procedure
has failed, then a computed tomography scan is made. If the scan demonstrates
an osseous defect that is longer in the sagittal plane than the maximum radius
of the glenoid, an anatomic glenoid reconstruction is
performed48.
Glenoid Reconstruction with Iliac Crest Bone Graft
Bodey and Denham were, to our knowledge, the first to report on the use of
this technique, in 1983, in sixteen shoulders with recurrent anterior
dislocation75. The
results were generally good, with all patients returning to their preoperative
level of work and sports activities. Glenoid grafting restores bone to
recreate the arc of the glenoid (Figs.
4-A and
4-B). Haaker et al. reported
that, of twenty-four soldiers treated with this technique, none had a
recurrence of the
instability76.
Hutchinson et al. reported excellent results, with no recurrences, in fourteen
individuals with epilepsy who were treated for recurrent anterior shoulder
dislocation77. In
most
studies76,77,
the patients have been satisfied, there has been a low recurrence rate, and
motion loss has been <10°.

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Fig. 4-A Illustrations demonstrating an anatomic glenoid reconstruction with
autogenous iliac bone graft. The graft restores the articular arc and
glenohumeral stability.
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Coracoid Process Transfers
Latarjet first described a technique of coracoid abutment in
195818. This
technique of coracoid transfer was later popularized and modified by
Helfet17, who named
it for his mentor Rowley Bristow. The aim of these procedures is to stabilize
the shoulder with the static action of the transferred bone block and the
attached coracobrachialis tendon. In the Latarjet procedure, the coracoid
process is osteotomized posteriorly at the junction of its horizontal and
vertical parts, and then it is transferred. Only the tip of the coracoid
process is transferred in the Bristow procedure, whereas, in the Latarjet
procedure, the transfer includes a portion of the coracoacromial ligament,
which is sutured to the capsular tissue through a short horizontal incision
made in the subscapularis (Fig.
5). The Latarjet procedure reconstructs the glenoid depth and
width with the bone block and creates a dynamic reinforcement of the inferior
part of the capsule through the coracobrachialis muscle, particularly when the
arm is abducted and externally rotated. These techniques are non-anatomic
reconstructions and distort the normal anatomy. Although they are often
successful, they may fail to address the essential lesion (i.e., the Bankart
lesion), to address any associated pathology (SLAP lesion), and to restore the
capsule.

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Fig. 5 Illustration demonstrating a coracoid bone graft (Latarjet procedure) being
used to restore bone in a glenoid deficiency. The coracoid is osteotomized at
its base and then transferred to the anteroinferior aspect of the glenoid with
the conjoined tendon. (Reprinted, with permission, from:
Burkhart SS, Debeer JF, Tehrany AM,
Parten PM. Quantifying glenoid bone loss arthroscopically in shoulder
instability. Arthroscopy.2002
;18:488
-91.[Medline])
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Nevertheless, transferring the coracoid process does provide reliable and
durable stabilization of the
shoulder21-25.
Recurrence rates have ranged from 0% (of fifty-eight procedures in the study
by Allain et al.22)
to 6% (seven recurrences in 111 patients in the study by Hovelius et
al.78 and three in
fifty-two patients in the study by
Levigne79). The
average loss of external rotation has ranged from 6° in the study by
Levigne to 23° in that by Torg et
al.80. The motion
loss is generally greater than that after an open Bankart procedure, which is
usually around
10°1,9,64.
More recently, some surgeons have advocated the addition of a coracoid bone
block transfer to a standard Bankart repair for athletes who engage in
collision
sports81.
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Humeral Bone Deficiency
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Humeral head defects are commonly present in patients with anterior
shoulder instability. The defects are usually small and are called
Hill-Sachs
lesions82.
The management of large lesions remains controversial. Furthermore, the
quantification of these defects is difficult given the geometry of the humeral
head. Humeral head defects are much more important when there is an associated
glenoid defect.
When the glenohumeral joint dislocates, the Hill-Sachs lesion can occur at
any of a variety of joint angles as determined by the position of the humerus
at the time of the dislocation. Some Hill-Sachs lesions engage the anterior
glenoid rim when the glenohumeral joint is in a position of abduction and
external rotation. Burkhart and De Beer described these as "engaging
Hill-Sachs
lesions."33
They can be defined as defects in which the long axis of the humeral head
defect aligns parallel to the anterior glenoid rim, when the shoulder is in a
position of abduction and external rotation. Such fracture configurations have
been found to be particularly prone to recurrent dislocation and subluxation
after arthroscopic repair. If combined with a glenoid defect, they can be
particularly problematic. Hovelius et al. found substantial Hill-Sachs defects
in 54% of their study population of 247 individuals with primary anterior
instability, and furthermore they found a higher risk of recurrence if a
Hill-Sachs defect was
present83. Rowe et
al. also suggested that a Hill-Sachs lesion could be a reason for failure
after open surgical
repair2. Other
authors, however, have found that the presence and magnitude of a Hill-Sachs
lesion did not influence the result of an open Bankart
repair84.
With a "non-engaging" Hill-Sachs lesion, the long axis of the
defect crosses diagonally across the glenoid rim with the arm in abduction and
external rotation so that it never "engages" the glenoid rim.
There is continuous smooth articular contact throughout the range of motion.
According to Burkhart and De Beer, shoulders with a non-engaging Hill-Sachs
lesion are not at substantial risk for recurrence after repair and therefore
patients with this type of humeral lesion are good candidates for that type of
repair33.
Clinically relevant, large humeral head defects are rare. They are usually
diagnosed on the basis of recurrent symptoms of instability and locking or on
the basis of three-dimensional imaging studies. It has been suggested by some
that the morphology of the Hill-Sachs defect is a prognostic factor for the
degree of
instability85.
Burkhart and Danaceau suggested that the mismatch in the articular arc that
occurs with a Hill-Sachs lesion is the important pathoanatomic
feature86.
Most Hill-Sachs lesions are simply ignored at the time of surgery, and the
anterior aspect of the capsule and labrum are addressed with an anatomic
repair, as discussed previously. When the bone defect is large, however, it
may need to be addressed. Unfortunately, there are no guidelines in the
literature about the size of defect that requires surgical treatment. We
become concerned when the defect exceeds 20% to 30% of the humeral head as
measured on a computed tomography scan or when a humeral head defect is
combined with a glenoid defect.
Surgical options for the management of humeral head defects include
reconstruction of the humerus with an allograft to restore the humeral
articular arc, reconstruction of the glenoid with an anterior bone graft to
lengthen the glenoid articular arc and prevent the humeral defect from
engaging the glenoid rim, or rotation of the humeral head with an osteotomy to
move the defect so that it does not come into contact with the anterior aspect
of the glenoid. If there is an associated glenoid defect, we recommend that
the glenoid be reconstructed first; if the humeral defect is still marked, it
can be reconstructed with an allograft. However, the evidence for each of
these approaches is largely anecdotal and based on small series or case
reports86-88.
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End-Stage Instability
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In rare cases, individuals will continue to complain of instability despite
attempted surgical reconstructions. In certain salvage settings, glenohumeral
arthrodesis may be the only option
available58,59;
however, Richards et
al.89 made the
sobering observation that many of these patients had sensations of instability
despite radiographic evidence of a solid fusion. Moreover, in some of these
patients, problems with the scapulothoracic joint developed as a result of
severe posturing, secondary scapular winging, pseudo-winging, and a snapping
scapula. These symptoms may occur as a result of, or be aggravated by, the
arthrodesis89.
Despite the concerns about arthrodeses, there may be no other reasonable
surgical option for this subcategory of patients.
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Revision and Complex Problems
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Revision surgery for shoulder instability is among the most technically
challenging of all. Nevertheless, it can also be among the most satisfying
procedures if basic principles are observed. When non-anatomic repairs need to
be revised, the normal tissue planes are often distorted. This adds technical
complexity to the procedure and increases the risk of complications. When
attempting to salvage failed repairs for anterior instability, surgeons should
be prepared to face challenging scenarios such as distorted anatomic tissue
planes, severe scarring, capsular deficiencies from multiple prior surgical
procedures or thermal
capsulorrhaphy90,91,
osseous deficiencies due to erosion or fracture, and subscapularis
deficiencies.
Capsular Deficiency
Capsular deficiency is a rare condition, and there is a paucity of
literature dealing with soft-tissue deficiency in relation to
instability92-95.
Capsular deficiency is more common in revision settings and after thermal
capsulorrhaphy. The soft-tissue deficiency may include the subscapularis.
There are several reasonable surgical options for an unstable shoulder with a
deficient capsule. Lazarus and Harryman described a method of using hamstring
tendons for repair of such
deficiencies96, and
Warner et al. reported good outcomes after using a modification of that
technique95. The
long head of the biceps can be combined with the autograft for additional
support. Presently, this is our preferred method for treating anterior
shoulder instability in the setting of capsular deficiency (Figs.
6-A and
6-B).

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Fig. 6-A Illustration demonstrating anterior capsular deficiency. (Reprinted from:
Warner JPJ, Venegas AA, Lehtinen
JT, Macy JJ. Management of capsular deficiency of the shoulder. A report of
three cases. J Bone Joint Surg Am.2002
;84:1669
.)
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Fig. 6-B Illustration demonstrating capsular reconstruction, with use of the
hamstring tendons, performed to address a deficient anterior aspect of the
capsule. (Reprinted from:
Warner
JPJ, Venegas AA, Lehtinen JT, Macy JJ. Management of capsular
deficiency of the shoulder. A report of three cases. J Bone Joint Surg
Am. 2002;84:1669.)
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Gallie and Le Mesurier described the use of the iliotibial band for
capsular reconstruction to treat glenohumeral instability associated with an
irreparable
capsule97. More
recently, Iannotti et al. reported their experience with this technique in
seven patients92.
The results were generally good, with no recurrences or problems with
persistent apprehension.
Moeckel et al. described the use of Achilles tendon allograft in ten
patients who had persistent anterior instability following shoulder
arthroplasty (in a series of 236 total shoulder
arthroplasties)93.
The results were generally fair to good with some loss of motion but
restoration of stability.
Subscapularis Tendon Tears
Rupture of the subscapularis in association with primary anterior shoulder
instability is a rare condition, and the diagnosis can be subtle. It is more
common after a prior open repair for the treatment of instability, and it
should be suspected in patients who have had a prior anterior stabilization
procedure in which the subscapularis was released for
exposure98.
Subscapularis tears can also occur after shoulder arthroplasty with anterior
instability of the prosthesis, although discussion of this topic is beyond the
scope of this article. Failure to recognize and treat a subscapularis tear in
a proper and timely fashion can result in a poor outcome. A careful physical
examination to assess the subscapularis is necessary. Individuals with
subscapularis deficiency have increased passive external rotation and positive
belly-press and lift-off
signs99,100.
A computed tomography-arthrogram or magnetic resonance imaging-arthrogram can
also be helpful for evaluation of the structural integrity of the
subscapularis tendon. Three-dimensional imaging allows quantification of
muscle atrophy, which is best observed on the axial and sagittal oblique
views101. On rare
occasions, individuals who have had prior surgery have subscapularis
dysfunction due to denervation of the muscle, and in such settings an
electromyogram may be helpful.
There are several published studies on rupture of the subscapularis tendon
in association with
instability13,94,102-107.
Hauser102 was, to
our knowledge, the first to describe an isolated tear of the subscapularis
tendon in association with anterior instability. Neviaser et
al.108 emphasized
that a rupture of the subscapularis tendon should be suspected in all patients
with recurrent instability and in older patients after an initial anterior
dislocation of the shoulder. Results of surgical treatment of subscapularis
tendon tears are less successful than those of supraspinatus tears. Gerber and
Krushell100
emphasized the importance of a timely diagnosis and early surgical management.
Results are better if the duration between the traumatic event and the repair
is short. A delay in diagnosis leads to retraction of the tendon and atrophy
of the muscle so that tendon mobilization becomes difficult. Results of
surgical repair are usually good with regard to pain relief and restoration of
stability, but many patients continue to have mild-to-moderate internal
rotation
weakness100,105.
When the subscapularis tendon is deficient or irreparable, a pectoralis
major muscle transfer may be used to augment or substitute for the
subscapularis. Gerber and
Krushell100
originally described the technique for mobilization and repair of the
subscapularis tendon and recommended that the inferior portion of the
subscapularis tendon be repaired so that the pectoralis major transfer can be
used simply to augment the function of the deficient upper part of the tendon
(Fig. 7). There have been
several reports on transfer of the pectoralis major tendon for treatment of
anterior shoulder
instability66,94,100,109-111.
Decreased pain and restored stability are the main benefits of this surgery.
Usually, functional gains in terms of mobility are variable and more limited.
Even when flexion and abduction are improved, many individuals remain limited
with regard to their ability to perform overhead activities. In the majority
of instances, the lift-off test and the bellypress test remain positive
postoperatively.

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Fig. 7 Illustration demonstrating a pectoralis major transfer for the treatment of
subscapularis deficiency with the technique of Gerber and
Krushell100. The
entire pectoralis major is transferred superiorly to the lesser tuberosity to
substitute for the deficient subscapularis. (Reprinted from:
Jost B, Puskas GJ, Lustenberger A,
Gerber C. Outcome of pectoralis major transfer for the treatment of
irreparable subscapularis tears. J Bone Joint Surg Am.2003
;85:1947
.)
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Complications and Pitfalls
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Recurrence of Instability
Recurrence is the most frequently reported complication after open and
arthroscopic surgery for the treatment of anterior
instability2,26,27,96,112-118.
Recurrence may be secondary to a new traumatic event or to atraumatic
events112,119,120.
Patients with a traumatic cause for the recurrence usually have better results
after revision surgery than do patients with atraumatic
recurrence62. The
recurrence rate is related to the number of prior operations. For example,
Levine et al.62
found that the recurrence rate was 17% in patients who had had one prior
operation, whereas it was 44% in individuals with multiple prior failed
surgical procedures. The repetitive damage to the subscapularis and the
capsule undoubtedly compromises the results of additional surgery.
A variety of factors can contribute to the failure of open surgical
treatment of anterior instability. The most common are an incorrect diagnosis,
an incorrect or technically inaccurate surgical procedure, a bone defect with
loss of glenoid concavity, and anterior capsular deficiency. Examples of
misdiagnoses are a failure to recognize posterior or multidirectional
instability
patterns27,54,112,116,121,
a failure to diagnose a substantial voluntary component to the
instability61,122,
and a failure to recognize and treat associated injuries. Incorrect or
technically imprecise surgical procedures can also lead to recurrence.
Subscapularis rupture is a complication of faulty technique that can be
devastating. Numerous studies have shown that residual Bankart
lesions123,
undercorrected anterior capsular redundancy, and unrecognized laxity of the
rotator
interval2,26,27,31,39,62,113,123
result in recurrent instability. As discussed previously, a defect in the
glenoid concavity due to an osseous Bankart lesion or an erosion of the
anterior glenoid rim increases the risk of
recurrence54,69-71.
Stiffness
Stiffness after surgery for the treatment of open anterior instability has
been noted infrequently in the literature, and the prevalence is probably
underreported71,119,124.
Certain anatomic repairs were designed to limit external rotation and hence
the risk of recurrence, so loss of motion was not considered a complication.
In some settings (e.g., capsular reconstruction or revision surgery), limited
external rotation remains an expected outcome, and this should be conveyed to
patients preoperatively. While loss of 10° of external rotation may have
little functional consequence for most individuals, it may be devastating for
an athlete who engages in overhead sports. This is an important point that
should be considered when selectively shifting the capsule. Overconstraint
should be avoided, as an overconstrained joint has abnormal kinematics, with
shear across the articular cartilage and altered joint reactive
forces125.
Harryman et al.126
showed that passive motion of the glenohumeral joint is coupled reproducibly
with translation of the humeral head on the glenoid. When the anterior aspect
of the capsule is overly tight, the humeral head has excessive posterior
translation with external rotation. This posterior translation creates
shearing forces on the posterior glenoid rim that may result in cartilage
erosion and early
osteoarthrosis119,121,127.
This phenomenon has been called "capsulorrhaphy arthropathy" or
"arthritis of dislocation" and results from loss of motion with
subsequent cartilage deterioration and joint arthrosis. Unfortunately, there
is no clear threshold beyond which these biomechanical consequences are
realized; however, a loss of external rotation of >30%, as compared with
the external rotation of the contralateral shoulder, increases the risk of
capsulorrhaphy
arthropathy119,121,127.
Motion loss is best prevented at the time of the surgical repair by
physiologically tensioning the capsule while the arm is in abduction and
external rotation. To avoid overconstraint, a rule of thumb has been to
position the shoulder in 30° of external rotation and 30° of
abduction. Furthermore, proper postoperative rehabilitation can prevent the
development of excessive stiffness. When refractory motion loss persists, a
formal capsular release may be
considered125.
Subscapularis Deficiency
Rupture of the subscapularis after an open repair for the treatment of
anterior instability causes substantial functional disability, which may or
may not be associated with recurrence of instability. Often, such tears are
not recognized when patients present postoperatively with weakness and pain
but no clear evidence of recurrent instability. A high index of suspicion and
a careful physical examination are necessary in order to detect this
problem.
When a subscapularis rupture occurs, repair poses a real surgical challenge
and a risk of injury of the surrounding neurovascular
structures128-130.
Unless the rupture is detected and addressed quickly, the subscapularis muscle
and tendon often retract and adhere to the surrounding structures. The
axillary nerve, musculocutaneous nerve, and brachial plexus are all at risk.
This problem is best avoided by meticulous repair of the tendon. If the
subscapularis ruptures, a direct repair of the tendon is often successful. In
chronic cases, tendon transfer of the pectoralis major is necessary, as
previously
described100,109,110.
Arthrosis
Glenohumeral arthrosis is a well-described complication of various surgical
procedures done to correct shoulder
instability21,22,67,131-135.
Overtightening of the anterior structures, with stiffness, can drive the
humeral head posteriorly, creating shear on the cartilage and early arthrosis.
Paradoxically, some patients may have instability and stiffness. The shoulder
feels unstable because of excessive laxity in the axillary pouch and an
untreated inferior glenohumeral ligament detachment, yet it feels stiff
because the middle glenohumeral ligament, the rotator interval, and sometimes
the subscapularis are excessively tight. Complex releases with revision
capsular shift may be required. An example is a z-plasty subscapularis
lengthening combined with an anterior-inferior selective capsular shift.
Fortunately, such scenarios are rare.
Other causes of premature osteoarthrosis are iatrogenic, such as anterior
impingement on a coracoid bone block that was placed too far laterally along
the glenoid
rim21,22,78,80,
impingement on local hardware such as a screw, and incorrect intra-articular
placement of metal
anchors134.
Hardware Problems
Any surgical implant has the potential to break, loosen, and migrate.
Zuckerman and
Matsen134
emphasized that loose hardware in the shoulder can migrate and threaten the
vital structures of the thorax. They also reported that most of their patients
with hardware problems required additional surgery and had marked iatrogenic
chondral defects. Moreover, when hardware needs to be removed, there is always
the potential for leaving bone defects that require grafting.
Neurovascular Injuries
The axillary nerve, musculocutaneous nerve, and brachial plexus are at risk
during open surgery for the treatment of anterior instability. Injuries may
occur as a result of excessive tissue retraction, especially retraction of the
coracobrachialis; direct laceration; or suture entrapment. Fortunately, most
are transient neurapraxias. Shoulder surgeons should be comfortable locating
and isolating the axillary nerve, the musculocutaneous nerve, and the brachial
plexus, especially in revision settings. Of all of the operations described in
this review, the Bristow and Latarjet procedures are associated with the
highest risk of injury to the axillary and musculocutaneous
nerves79,128,130,136.
Revision surgery after a failed Bristow or Latarjet procedure can be quite
challenging, and exposing the axillary nerve in such instances can be
difficult.
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Overview
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While arthroscopic capsulolabral repair is becoming the standard of care
for the treatment of traumatic recurrent anterior shoulder instability, open
approaches are still reliable, time-tested options that in many instances
remain the gold standard. Despite tremendous advances in arthroscopic
technique, major bone loss, soft-tissue deficiencies, and revision situations
often require open approaches. As arthroscopic techniques continue to evolve,
surgeons should carefully and continuously redefine their indications on the
basis of their surgical skill and the spectrum of relevant pathological
conditions that may be faced. As detailed in this review, there are many
instances in both primary and revision surgery for the treatment of anterior
shoulder instability in which an open approach remains the preferred method of
treatment. A surgical approach that combines careful preoperative and
intraoperative evaluation with a skillful technique ensures the highest
possibility of good and excellent surgical outcomes.
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