Glenohumeral Joint Subluxations, Dislocations, and Instability

Initial management of shoulder dislocation begins with
identification of the injury. Often the patient may be able to clearly
recount the shoulder position as well as the direction of the applied
force. In other instances, this information may be more clearly
obtained from an eyewitness. Additional information regarding prior
shoulder injury, prior episodes of instability, and prior treatments
should all be documented. Hand dominance, occupation, activity level,
and general health history should also be obtained. A general survey of
the patient, including an adequate examination of the spinal column,
should then be performed. Inspection of the shoulder may reveal an open
wound, localized swelling, or a gross deformity. Often these
deformities can be best visualized by inspecting the patient from
behind, with the patient in a sitting position. With an anterior or
posterior glenohumeral dislocation, the humeral head may be palpable
beneath the skin.

A complete shoulder examination may not be possible
because of pain and muscle spasms. Whenever possible, however, the
limits of shoulder motion should be established as they may provide
insight into both the severity and the direction of the instability.
Patients with an anterior dislocation, for example, will typically
demonstrate limitations in internal rotation and abduction. In
contrast, patients with a posterior dislocation will often demonstrate
limitations in external rotation. In very rare instances, referred to
as luxatio erecta humeri, the patient may suffer from inferior glenohumeral dislocation with the arm locked in fully abducted position (Fig. 38-4).⁴⁵,²⁶⁸,²⁹²
Before any manipulation, a complete neurovascular examination of the
upper extremity must be performed and documented. The axillary nerve is
the most commonly injured nerve after an anterior glenohumeral
dislocation, with some electrodiagnostic studies reporting rates as
high as 60%.¹⁷,²⁶⁰ Therefore, both the motor and the sensory component of this nerve must be examined (Fig. 38-5). Although quite rare, vascular injuries following shoulder dislocations have also been reported.⁶⁵,¹⁴⁸

Patients with shoulder instability may present with a
variety of clinical symptoms. Some may present for definitive care
after being treated at a local emergency room for an acute shoulder
dislocation. Some may present with a recent exacerbation of a recurrent
instability. Others may present with a vague history of pain without
clinical suspicion or prior diagnosis of instability. Because of this
variability in presentation, the importance of an accurate and complete
history cannot be overemphasized.

As with all patients with a shoulder related complaint,
general orthopaedic information should be obtained first. This includes
age, occupation, hand dominance, level of sporting or recreational
activity, presence of any previous injury or surgery, and functional
impairments because of shoulder symptoms. If pain is the predominant
complaint, its characteristics such as severity, location, duration,
and precipitating position and/or activity must be clearly defined. In
contrast, if instability is the predominant complaint, the frequency
and the severity of the instability as well as the susceptible shoulder
positions should be elicited. Often these patients have been avoiding
specific tasks that involve placing their shoulder in a position
vulnerable to dislocations. As such, details of their functional
limitations may provide clues to the direction and the severity of the
instability.

Whenever possible, the mechanism of shoulder instability
should be defined clearly. This includes the timing, the amount of
applied energy, the position of the shoulder at the time of the impact,
and the degree of instability. For patients with recurrent instability,
the severity of force associated with a recent exacerbation may be
slight such as raising the arm or reaching for an object. Any history
of previous shoulder instability should prompt questions regarding the
nature of the injury as well as any prior treatments. Clinical
evaluation of patients with recurrent instability should include
questions regarding voluntary instability. Any issues regarding a
secondary gain from shoulder instability should also be defined. If a
patient can dislocate the shoulder voluntarily, it should be observed
firsthand in order to identify the position of the arm, the amount of
needed effort, and the direction of dislocation. In addition, these
patients should be queried for any associated neurologic signs such as
weakness, numbness, and tingling sensations.

Examination of an unstable shoulder can be quite
challenging. Some of the findings may be subtle, and the ultimate
diagnosis may be difficult to establish. In patients who have suffered
a recent instability episode, associated symptoms may be severe enough
to preclude an adequate examination. For these patients, a basic
examination to document glenohumeral joint reduction and neurologic
status may be all that can be accomplished during the initial visit. If
so, they should be evaluated more thoroughly at a later date when
majority of the pain has subsided. A detailed neurologic examination of
the upper extremity must be performed and documented during all
clinical evaluations.

A thorough examination of the shoulder begins with
inspection. Any abnormalities such as asymmetry, muscular atrophy,
localized edema, or ecchymosis should be noted. This is usually
followed by manual palpation for localized tenderness and bony defects.
Range of motion of the affected shoulder should be obtained and
compared with the contralateral shoulder. In addition, differences
between active and passive range of motion should be noted. If
possible, the etiology of this difference, whether caused by pain,
weakness, or both, should be determined. General strength testing is
performed with specific maneuvers to identify rotator cuff weakness.
This is particularly important for an older individual, because the
association between

rotator cuff tears and shoulder dislocations increases significantly with age.¹⁹¹
Findings consistent with a generalized systemic laxity are also noted.
These include elbow hyperextension, hyperflexion of the wrist (thumb to
forearm maneuver), hyperextension of the metacarpophalangeal joints,
and knee hyperextension (Fig. 38-6).
Provocative maneuvers for shoulder instability are typically reserved
for the end of the examination as they may reproduce the clinical
symptoms of pain and apprehension. For most techniques, the maneuver
should be performed bilaterally to compare and contrast the symptomatic
shoulder with the asymptomatic shoulder.

One of the most widely used examinations of instability
is the “drawer” test. This maneuver can be performed either with the
patient in the sitting or supine position. It can be used to assess
both anterior and posterior instability. It has been suggested that
this maneuver is most reliable if the arm is held in 80 to 120 degrees
of abduction, 0 to 20 degrees of forward flexion, and 0 to 30 degrees
of external rotation.⁸ If the
patient is supine, the entire shoulder should be off the table to allow
free access to the shoulder girdle. While the shoulder girdle is
manually stabilized with one hand, the other hand manipulates the
humeral head for anterior translation (Fig. 38-7).
For normal shoulders this translation should be smooth with a firm
endpoint. If the translation is excessive in comparison with the
contralateral shoulder, or if the maneuver reproduces the clinical
symptoms of apprehension or pain, a presumed diagnosis of anterior
instability can be established. This is a reliable test when the
patient is able to relax the shoulder muscle sufficiently and allow the
maneuver to be performed without tension.⁵⁵
In addition to anterior instability, the same maneuver can also be
adjusted to test for posterior instability. This is accomplished by
manually translating the humeral head posteriorly. Again, posterior
instability is suspected if the maneuver reproduces pain or
apprehension. In this fashion, the “drawer” test can be used to test
for instability in multiple directions.

A variant of the drawer test is the “load shift” test.²⁵⁰
Unlike the “drawer” test, the arm is placed in 20 degrees of abduction
and 20 degrees of forward flexion. Rotation is maintained at neutral,
and longitudinal pressure is applied to the humeral head in order to
load the glenohumeral joint. Similar to the “drawer” test, the humeral
head is then grasped and translated in either the anterior or posterior
direction to assess for laxity and pain.⁸

Although it is generally used to test for inferior
laxity, the “sulcus” test is often positive in many patients with
multidirectional instability (Fig. 38-8).¹⁸⁷
This maneuver is performed in the sitting position with the shoulder
fully adducted. By manually placing downward traction on the arm,
inferior translation of the humeral head is created. Significant
translation will produce a noticeable “dimple” or “sulcus” at the
lateral edge of the acromion. By placing the shoulder in external
rotation, the sulcus test can also be used to estimate the integrity of
the rotator interval structures such as the coracohumeral ligament and
the superior glenohumeral ligament. External rotation of the shoulder
should place these structures under tension and allow them to act as a
restraint to inferior translation. As such, a positive sulcus sign with
the shoulder in external rotation would suggest excessive laxity within
the structures of the rotator interval.⁸

The “apprehension” test specifically examines anterior instability of the glenohumeral joint.²³⁹ This maneuver is designed

to cause the feeling of imminent dislocation (apprehension) in patients
as their shoulder is placed in a position that is vulnerable to
dislocation. The patient is placed in the supine position with the
shoulder slightly off of the table. The shoulder is then positioned in
90 to 100 degrees of abduction and neutral rotation. From this point,
the shoulder is externally rotated until it reaches its maximal limit
or until the feeling of apprehension is reported by the patient (Fig. 38-9A).
Some patients may report pain instead of apprehension. Although pain
may be used as an indicator for instability, it is typically not as
specific or as reliable as apprehension in documenting anterior
instability.⁵⁵,¹⁵⁵
Modifications of this maneuver that try to either exaggerate or
diminish the instability have also been described. As such, the
“fulcrum” (Fig. 38-9B) and the “crank” test (Fig. 38-10)
are similar to the “apprehension” test, but an anteriorly directed
force is placed on the posterior aspect of the shoulder to exaggerate
the instability. In contrast, in the “relocation test,” a posteriorly
directed force is placed on the anterior aspect of the shoulder to
eliminate the feeling of apprehension (Fig. 38-11).
Finally, the “surprise” test is another variation of the apprehension
test where the examination starts with a posteriorly directed force on
the anterior shoulder. As this force is manually stabilizing the
glenohumeral joint, the patient does not experience apprehension even
when the shoulder is placed in abduction and maximal external rotation.
By abruptly removing this force, the patient will suddenly experience
apprehension or pain. Although all these maneuvers can detect anterior
instability, a recent study has suggested that the surprise test may be
the most accurate.¹⁵⁵

In contrast to these maneuvers that examine anterior
instability, the “jerk” test is a provocative maneuver for posterior
glenohumeral instability (Fig. 38-12).¹³³
This maneuver can be carried out with the patient in either the sitting
or supine position. Again, if the patient is in the supine position,
the shoulder should be slightly off the table. After elevating the
shoulder to 90 degrees in the plane of the scapula, an axial load is
placed on the humerus such that the humeral head is compressed against
the glenoid. This can be easily accomplished by pushing axially against
the flexed elbow. By gradually adducting the shoulder, the humeral head
may subluxate or even dislocate posteriorly and produce a sudden jerk.
When the shoulder is taken out of adduction, the humeral head will
abruptly reduce back onto the glenoid and produce another jerk. The
findings from this test can be quite dramatic in patients with
posterior instability. Because of guarding, however, a positive finding
may be difficult to elicit in an awake patient. As such, instead of the
jerk, the test can also be considered positive if the maneuver elicits
the sensations of apprehension or pain.

Although all these provocative maneuvers can be informative,

voluntary or involuntary guarding may compromise the reliability of the
examination. If a clear diagnosis of instability cannot be established,
examination under anesthesia should be considered in select cases.
After adequate anesthesia and sedation, patients are unable to guard
against instability and the same provocative maneuvers can be performed
in a controlled environment. In addition, even with an established
diagnosis, examination under anesthesia should always be performed
prior to initiating any surgical procedure in order to confirm the
diagnosis.

The scapula has a complex three dimensional structure.
Notable parts of the scapula include the body, the spine, the acromion,
the glenoid, and the coracoid process (Fig. 38-23A).
Parts of the scapula articulate with the distal clavicle and the
humeral head to form the acromioclavicular and the glenohumeral joints,
respectively. The scapula rests on the posterior aspect of the thoracic
cage and is stabilized by the periscapular musculature. The glenoid
surface is located on the lateral aspect of the scapula such that its
surface has a slightly superior inclination relative to the vertical
axis of the body. This inclination has been shown to play an important
role in augmenting inferior stability of the glenohumeral joint.¹¹⁵
In addition, the scapula is anteverted 30 to 40 degrees in respect to
the coronal axis of the body, whereas the glenoid surface is roughly
orthogonal to the plane of the scapula.³⁷
Therefore, the glenoid surface is anteverted 30 to 40 degrees and faces
anterolaterally in respect to the coronal axis of the human body. This
glenoid anteversion, in turn, is matched by the retroversion of the
humeral head. With the humerus in neutral rotation (i.e., the forearm
pointing forward in respect to the body), the humeral head faces
posteromedially. In this fashion, the perpendicular axis of the humeral
head corresponds to the perpendicular axis of the glenoid fossa in
normal shoulders (Figure 38-23B).

The surface geometry of the glenoid was once believed to
be elliptical, with a vertical diameter that is greater than its
horizontal diameter. Unlike a typical symmetric ellipse, the inferior

glenoid
surface has a slightly greater horizontal dimension than the superior
glenoid surface. In fact, the inferior 2/3 of the glenoid roughly
approximates a circle, whereas the overall glenoid surface is “pear
shaped.”¹⁰⁸
The size of the humeral head can vary widely between individuals;
however, there appears to be a direct correlation between height and
the diameter of the humeral head such that a taller person typically
has a larger humeral head.¹¹⁰
Morphology of the humeral head is nearly spherical in shape, but the
articular cartilage has variable thickness along different axes. Thus,
the peripheral contour of its articular surface is also slightly
elliptical.¹¹⁰

The interaction between the humeral head and the glenoid
fossa has been intensely scrutinized and found to be very precise. For
most shoulder movements, the center of the humeral head is located
within 1 millimeter from the central axis of the glenoid cavity.¹⁰⁵
This is somewhat surprising because the overall size of the humeral
head is significantly greater than that of the glenoid. As such, at any
given position, the majority of the humeral head does not contact the
glenoid and remain “uncovered.”

In addition, the radius of curvature of the glenoid
surface also does not correspond to that of the humeral head. On
average, the radius of curvature of the glenoid is greater (less
curved) by 2.3 millimeters.¹¹⁰
Although this mismatch in size and radius of curvature may produce
decreased joint stability, it also prevents impingement of the proximal
humerus against the periphery of the glenoid. The end result,
therefore, is increased range of shoulder motion.

The bony anatomy of the glenohumeral joint has minimal
inherent constraints that allow for a large range of motion. The
majority of glenohumeral stability, therefore, is provided by the
various soft tissue structures that surround the joint. One of the most
important of these stabilizing structures is the glenoid labrum. The
labrum is a dense fibrous tissue which circumferentially surrounds the
glenoid. It is contiguous with the glenoid rim and interacts with the
glenohumeral ligaments and the intra-articular synovium (Fig. 38-24). The importance of the labral tissue to the overall joint stability has been well described in the literature.¹¹,¹²,¹⁴⁶
Correlation between traumatic anterior shoulder dislocations and an
anteroinferior labral defect is extremely high. As such, this labral
defect has been termed the “essential lesion.”¹¹,¹²

Despite the high association with instability, the
mechanism by which the labrum confers stability to the glenohumeral
joint is somewhat unclear. The anterior labrum may augment stability of
the joint by providing a secure attachment site for the glenohumeral
ligaments. Some earlier studies demonstrated that if the ligament
attachment sites can be maintained, excision of the labrum did not seem
to affect glenohumeral stability.²¹⁹,²⁶⁹
Anatomically, the labrum effectively enlarges and deepens the glenoid
surface by 1 centimeter and 50%, respectively, and provides additional
surface to interact against the humeral head.¹⁰⁴
Therefore, the labrum may provide stability to the joint by creating
additional surface for humeral head translation. Recent cadaveric
studies support this hypothesis as they demonstrated that if a labral
defect is created, the humeral head is no longer centered within the
glenoid fossa and the joint becomes increasingly unstable.⁵⁷,¹⁴⁶

The glenoid and the humeral head are enclosed within the
glenohumeral capsule. The joint capsule is generally loose and
redundant at most shoulder positions. At extremes of motion, however,
the capsule tightens and provides stability to the joint. Thus,
depending on the position of the shoulder, certain portions of the
capsule will tighten and act as a restraint against humeral head
translation. Studies have confirmed that different parts of the
glenohumeral capsule can act as a primary or a secondary stabilizer
against shoulder dislocation in all directions.²⁰¹,²⁴⁷

The capsule completely encompasses the joint such that
it maintains a stable and finite joint volume. In normal shoulders,
this finite volume provides stabilizing force on the joint, as
distracting the humeral head away from the glenoid will create a
relative vacuum within the capsule. In fact, physiologic
intra-articular pressure within the glenohumeral joint is slightly
negative.

Osmotic
action of the synovium is believed to remove free fluid from the joint,
thus creating a slightly negatively intra-articular joint pressure.¹⁴⁹
When the capsule is vented and opened to the atmosphere, the force
necessary to translate the humeral head decreases significantly.⁷¹,⁸¹,¹³⁹
The stabilizing force generated by the finite joint volume and the
associated negative intra-articular pressure may be as high as 146 N.
During a dislocation, the capsule undergoes a plastic deformation,
which may result in increased capsular volume.⁴⁹ This static stabilizing force has been demonstrated to be diminished in patients with shoulder instability.⁸¹

The glenohumeral ligaments are some of the most
important static stabilizers of the glenohumeral joint. They include
the superior glenohumeral ligament, the middle glenohumeral ligament,
the inferior glenohumeral ligaments, and the coracohumeral ligament.
All three glenohumeral ligaments are intimately associated with the
joint capsule. In fact, these ligaments were once believed to be variable thickenings within the joint capsule.⁴⁰
Multiple studies, however, have demonstrated that the glenohumeral
ligaments are consistently present and that they are clearly
distinguishable from the capsule.¹⁷¹,²²⁰

The superior glenohumeral ligament originates from the
anterior superior aspect of the glenoid and extends to the anterior
aspect of the humeral head just superior to the lesser tuberosity.
Biomechanical studies have demonstrated that this ligament acts as the
primary restraint to inferior translation in the adducted shoulder, and
as a secondary restraint to posterior humeral head translation.²⁴⁷,²⁷⁷
The middle glenohumeral ligament has a variable origin as it can arise
from the supraglenoid tubercle, anterosuperior aspect of the labrum, or
the scapular neck. It can be quite dense and “cord-like” in some
patients but practically nonexistent in others.¹⁸⁶
This ligament often becomes confluent with the tendon of the
subscapularis muscle and attaches to the inferior aspect of the lesser
tuberosity. In addition to acting as a secondary stabilizer against
anterior humeral head translation, the middle glenohumeral ligament
also appears to provide a restraint to excessive external rotation when
the shoulder is in approximately 45 degrees of abduction.²⁴⁷
The inferior glenohumeral ligament consists of three different
components: the superior band, the anterior axillary pouch, and the
posterior axillary pouch.¹⁹⁷ This
ligament originates from the anteroinferior aspect of the labrum and
extends to the inferior aspect of the lesser tuberosity. The inferior
glenohumeral ligament complex has been compared to a hammock-like swing
that surrounds and supports the humeral head when the shoulder is
abducted.¹⁹⁹ As such, this ligament
has been demonstrated to be the primary stabilizer against anterior and
posterior translation of the humeral head, as well as being a restraint
against excessive external rotation of the abducted shoulder.²³,¹⁹⁸,²¹⁹

In a majority of the unstable shoulders, these ligaments
are compromised from their origin at the glenoid. It has also been
demonstrated, however, that the ligaments and the capsule may be
damaged in midsubstance or at their insertion in the humeral head.¹⁸²,¹⁹³ Both of these injuries may occur as an isolated entity or in conjunction with other lesions such as labral defects.²²⁴

In contrast to the glenohumeral ligaments, the
coracohumeral ligament originates from outside the joint. It arises
from the lateral aspect of the coracoid process, passes within the
interval between the subscapularis and the supraspinatus tendons (i.e.,
the rotator interval), and attaches to the lesser and greater
tuberosities.¹²⁴ This structure is
tight when the shoulder is adducted and becomes loose when the shoulder
is abducted. 13 Therefore, the coracohumeral ligament is believed to

prevent
excessive external rotation when the arm is adducted. In addition, this
ligament is also believed to stabilize the joint against inferior
subluxation when the arm is adducted.¹³,²⁰²

The rotator cuff consists of the subscapularis, the supraspinatus, the infraspinatus, and the teres minor muscles (Fig. 38-25).
Although these structures are generally considered to be dynamic
stabilizers of the glenohumeral joint, their tendons surround the joint
and often interdigitate with the joint capsule.³⁹ Therefore, even without muscle contractions, they can also act as static stabilizers of the glenohumeral joint.

During shoulder motion, muscle contractions may generate
a displacing force across the glenohumeral joint. Contraction of the
anterior deltoid muscle, for example, produces a posteriorly directed
force on the humeral head. If left unbalanced, this force can create
posterior shoulder instability. To counteract these forces, the rotator
cuff muscles selectively contract to maintain the humeral head centered
within the glenoid fossa. Thus, the rotator cuff muscles counterbalance
the displacing forces created by the contractions of other shoulder
girdle muscles. In this fashion, they act to dynamically stabilize the
glenohumeral joint.¹⁴¹,¹⁸⁶,²⁵⁹

In addition to countering displacing forces,
contractions of the rotator cuff muscles also generate a medially
directed force on the humeral head. This results in compression of the
humeral head against the glenoid fossa, which in turn provides
additional joint stability. Dynamic stability conferred by joint
compression appears to be active throughout all shoulder motion.¹⁴⁷,¹⁵⁴,²⁷⁶ In fact, sufficient joint compression can even overcome the destabilizing effects of ligament sectioning and joint venting.²⁷⁶
Thus, dynamic stability provided by the rotator cuff muscles may be
able to compensate for the loss of other stabilizing structures.

The proximal biceps tendon originates from the
supraglenoid tubercle, courses along the rotator interval, and exits
the glenohumeral joint into the bicipital groove of the humerus. The
physiologic role of the proximal biceps tendon has received much
attention, but remains somewhat controversial. Experimental studies
have shown that loading of the biceps tendon can decrease the tension
on the inferior glenohumeral ligament.²³³ Loading of the biceps tendon can also decrease humeral head translation in all directions, especially in the adducted shoulder.¹¹³,²⁰⁴
In fact, a cadaveric study demonstrated that loading of the biceps
tendon can prevent anterior shoulder dislocation even when the joint is
destabilized by venting or by creating a labral lesion.¹¹³
Thus, loading of the biceps tendon appears to provide a stabilizing
effect on the glenohumeral joint. Notably, a recent electromyographic
study demonstrated that when forearm position is controlled, the biceps
muscle remains electrically silent during all shoulder motion.¹⁵²
This has led to the conclusion that, physiologically, the biceps tendon
may not be under any significant tension during normal shoulder motion.
Without significant loading, it is unclear whether the biceps tendon
confers any additional stability to the glenohumeral joint.

Superficial to the rotator cuff tendons, the shoulder is
maintained within the confines of the coracoacromial arch. This arch is
formed by the coracoid process, the coracoacromial ligament, and the
acromion. These structural constraints limit the extent of
anterosuperior, superior, and posterosuperior translation of the
humeral head. In patients with a large rotator cuff tear, for example,
this arch often represents the last restraint to anterosuperior
glenohumeral dislocation. In normal shoulders with intact rotator cuff
tendons, there also appears to be contact and load transfer between the
coracoacromial arch and the rotator cuff tendons.⁶²,²⁹⁰
Therefore, during normal shoulder motion, a downward force is exerted
by the coracoacromial arch, through the rotator cuff tendons, onto the
humeral head to limit superior translation.

The skin incision is placed on the anterior axillary line starting from the coracoid process and extending distally (Fig. 38-26A).
In most patients, the surgical incision can be placed in line with the
axillary fold for improved cosmesis. After the skin incision and
subcutaneous dissection, the interval between the anterior deltoid and
the pectoralis major muscle is identified. This area, also referred to
as the deltopectoral interval, is outlined by the cephalic vein which
must be dissected and retracted away from the surgical field (Fig. 38-26B).
The cephalic vein is typically retracted laterally as most small
feeding vessels originate from the deltoid muscle. The underlying
clavipectoral fascia can then be incised to gain access to the shoulder
(Fig. 38-26C). The overlying subscapularis
tendon may be split in line with its fibers or it can be released just
medial to its insertion at the lesser tuberosity (Fig. 38-26D).
It must be stressed that rigid and anatomic repair of the subscapularis
tendon must be completed at the end of the procedure as good surgical
results correlate with subscapularis function.²⁴³ At this

point, the capsule is vertically incised to expose the joint and the anterior glenoid margin.

The skin incision is usually placed just medial to the
posterolateral corner of the acromion, extending to the axillary
crease. For access to the glenohumeral joint, traditional approaches
have released the deltoid muscle from its origin on the acromion.
Recent modifications of the approach, however, specifically avoid the
release of the deltoid origin. For most patients, adequate exposure can
be obtained by splitting the deltoid from the posterior acromion to the
upper border of the teres minor (Fig. 38-27). The theoretical advantage of this modification is the preservation of strength and function of the posterior deltoid.²⁸⁴
Once the rotator cuff tendons are exposed, the infraspinatus tendon can
be incised and reflected medially. Excessive medial reflection should
be avoided in order to prevent injury to the suprascapular nerve (Fig. 38-28).
In situations where the infraspinatus tendon is very lax, it may be
possible to simply retract the tendon superiorly instead of releasing
it. The teres minor muscle fibers are then retracted inferiorly to gain
exposure to the posterior capsule. Care must be taken when handling the
teres minor because the axillary nerve and the posterior humeral
circumflex vessels lie just inferior to this structure in the
quadrilateral space. Once the posterior capsule is isolated, it is
incised to expose the joint.

An acute shoulder dislocation is a condition that
requires emergent care. The joint should be reduced to its anatomic
position as soon as possible, and a closed reduction should be
attempted for most patients. In the select patients with concomitant
proximal humerus fractures, however, reduction under anesthesia should
be considered. The likelihood of a successful closed reduction is
dependent on multiple factors, including the presence of muscle spasm,
duration of the dislocation, presence of interposing structures, and
the availability of adequate assistance.

To obtain adequate muscle relaxation and pain control
during shoulder reduction, intravenous analgesic and sedation agents
are often used. Although these agents can be extremely valuable, their
use necessitates careful patient monitoring. In rare circumstances,
excessive sedation may even lead to a respiratory compromise that
requires formal airway protection. As such, administration of
intravenous agents typically requires the use of significant clinical
resources. Recently, some authors have reported that intra-articular
injection of lidocaine, rather than intravenous agents, can be used to
effectively control pain and muscle spasms during shoulder reduction.
They demonstrated that closed reduction after intra-articular lidocaine
injection had high rates of success, especially if the attempts were
performed within 5.5 hours after the dislocation.¹⁷⁶
When compared with those who received intravenous agents, these
patients were also shown to spend less time in the emergency room and
incur less expense.¹⁷⁶

After administration of either intra-articular or
intravenous analgesia, a closed reduction can be attempted. A number of
different reduction techniques and maneuvers have been described in the
literature.²⁸⁶ Some of the more
commonly utilized techniques are described below. All of these
techniques rely on appropriate positioning of the shoulder with gentle,
slow, and sustained traction on the arm. Sudden or forceful
manipulations are avoided because they can lead to significant
complications. If initial shoulder reduction is unsuccessful, the
degree of sedation and analgesia must be evaluated to ensure that
adequate muscle relaxation has been obtained. If closed reduction is
not successful, the patient should then be taken to the operating room
on an emergent basis for either closed or open reduction. Once closed
reduction is accomplished, anatomic reduction of the glenohumeral joint
must be confirmed with radiographs. In addition, postreduction
documentation of the neurovascular status must also be performed.

One of the earliest closed reduction techniques was originally described by Hippocrates (Fig. 38-29A).⁹²,⁹³
This method utilizes the concept of traction and countertraction to
distract the glenohumeral joint and is applicable for most shoulder
dislocations. If performed by a single person, countertraction can be
provided by a foot that is placed on the thorax just inferior to the
axilla. If assistance is available, countertraction can also be
provided by a sheet that is placed around the upper thorax and held
steady by an assistant (Fig. 38-29B). Against this countertraction, slow and steady traction is applied to the arm

to distract the humeral head away from the glenoid. Upon disengagement
of the humeral head from the glenoid rim, the traction is released, and
the joint is allowed to reduce back to its anatomic position. In some
instances, gentle rotation or manipulation of the humeral head may be
required to mobilize the humeral head.

A similar traction maneuver is also utilized in the Stimson technique.²⁵⁵
Following its original description, this technique has undergone a few
modifications. The patient is placed in prone position with the
affected arm hanging free over a table (Fig. 38-30).
In this manner, the table provides a stable base against which a gentle
downward traction is placed on the arm. The traction can be applied
manually or by attaching weights to the wrist. Typically, 5 pounds is
sufficient for most patients. Depending on the size of the patient,
however, the amount of weight can be varied accordingly. By applying
this traction for a period of time (10 to 20 minutes), the shoulder
musculature will fatigue and allow sufficient relaxation for humeral
head disengagement. The traction is then released, and the joint is
allowed to reduce back to its anatomic position.

Another commonly utilized reduction maneuver is the Milch technique, which is especially useful for anterior dislocations.¹⁷⁴
Unlike some of the other maneuvers, this technique relies on shoulder
position rather than distraction. The maneuver can be performed with
the patient in either supine or prone position. Upon administration of
analgesia and moderate traction, the arm is abducted and externally
rotated. The dislocated humeral head is then manually manipulated back
into the joint. Various authors have reported that this method is
associated with a high rate of success and with minimal complications.¹⁴²,²⁴¹

After a successful closed reduction that is confirmed by
radiographs, the arm should be immobilized for a period of time.
Although most surgeons agree that a brief period of immobilization

is
required for patient comfort and protection, the exact protocol for
immobilization is still controversial. Thus recommendations regarding
the type, duration, and position of immobilization have yet to be
firmly established.

In comparison to a simple sling, immobilization in a
Velpeau dressing, which includes a sling and a swath, does not appear
to alter the subsequent development of recurrent instability.⁵²
Therefore, since more rigid orthoses tend to be quite cumbersome, a
simple sling is preferred for most patients. As for the duration of
immobilization, some series have reported no correlation between the
duration of immobilization and the development of recurrent instability.⁹⁸,¹⁷²
In a prospective randomized study, for example, Hovelius and colleagues
showed that the type and duration of initial immobilization had no
affect on the development of recurrent instability.⁹⁷
In contrast, other studies have reported decreased rates of recurrent
instability in patients whose shoulders were immobilized for a short
period of time. For example, one study showed that patients who were
immobilized for more than 1 week demonstrated a significantly decreased
rate of recurrent instability in comparison with their nonimmobilized
counterparts.¹²⁸ In other studies,
the incidence of recurrent instability in patients who were immobilized
for less than 3 weeks was nearly twice that of those who were
immobilized for 3 weeks or longer.¹³⁶,²⁵⁶
One of these studies also demonstrated that the duration of
immobilization affected recurrent instability only in patients younger
than 30 years of age. For older patients immobilization had minimal
impact on recurrent instability.¹³⁶ Therefore, age of the patient should also be considered when deciding on the duration of postreduction immobilization.

In addition to the type and duration of immobilization,
the position of immobilization has also received significant attention.
A simple sling places the shoulder in internal rotation. Some studies
have suggested that this position may not be optimal in preventing
recurrent instability. In patients who sustained a traumatic anterior
shoulder dislocation, position of the anterior labrum after reduction
appears to be more anatomic if the arm is positioned in slight external
rotation.¹¹⁶ This radiographic
observation has been supported by a clinical study which demonstrated
that, at a relatively short-term follow-up period of 15 months,
patients immobilized in external rotation did not develop recurrent
instability. In contrast, patients who were immobilized in the
traditional internally rotated position demonstrated a recurrent
dislocation rate of 30%.¹¹² This
difference was even more striking for patients younger than 30 years of
age, as the rates of recurrent dislocation in the external and the
internal rotation groups were 45% and 0%, respectively.¹¹²

In contrast with these promising results, some of the
more recent studies have demonstrated no such advantage for
immobilization in external rotation. As such, a surgically created
Bankart lesion placed in external rotation did not demonstrate any
change in pressure between the glenoid and the capsulelabral complex.¹⁵³
Also, a recent study directly compared sling immobilization against
external rotation immobilization after a primary dislocation event in
patients less than 35 years old. Over 2-year follow-up, no significant
difference was noted between the groups, with the sling group having
27% rate of recurrent instability and the external rotation group
having a 23% rate of recurrent instability.²⁸²
With seemingly contradictory data, it appears that the consequences of
immobilization in external rotation are incompletely understood.
Therefore, further studies are still needed to optimize the
postreduction immobilization protocol.

Nonoperative management of patients with glenohumeral
instability relies on the principles of immobilization, protection, and
rehabilitation. Immobilization allows for general recovery of the
shoulder from the traumatic incident. In addition, immobilization also
allows for the initial healing of the static stabilizers. As discussed
in the previous section, the optimal protocol for the position and
duration of immobilization has not been clearly defined.

The second principle of nonoperative treatment is
protection. A brief period of immobilization is designed to protect the
shoulder from additional episodes of instability. Subsequent to this
initial phase, activity level of the patient must be modified to allow
for the healing of the static stabilizers. Activity patterns are
altered so that the shoulder is not placed in positions vulnerable to
dislocation. Typically, this is accomplished by limiting the range of
shoulder motion as well as refraining from participating in any
high-risk activities. Experiments in primates demonstrated that 3
months were required to restore normal collagen structural patterns in
the shoulder capsule, and that 4 to 5 months were required to restore
normal tensile strength.²¹⁹ Therefore, this may provide a reasonable guideline for the period of protection.

The final principle of nonoperative treatment is
rehabilitation. Dynamic stabilizers are strengthened to provide
additional stability for the compromised joint. Compression of the
glenohumeral joint by the rotator cuff muscles, for example, can
overcome the destabilizing effects of ligament sectioning and joint
venting.²⁷⁶ As such, muscle
rehabilitation may be able to compensate for the loss of some static
stabilizers. Specific protocols for rehabilitation of the shoulder can
vary; however, most protocols concentrate on strengthening the rotator
cuff as well as the deltoid muscles.³¹,²⁸⁶
In addition, some authors have also stressed the importance of
strengthening the periscapular musculature, as they allow the scapula
to function as a stable platform for shoulder motion.³¹,⁷³

The likelihood of successful nonoperative treatment for
shoulder instability can vary widely, depending on a multitude of
factors. For example, those with associated injuries such as rotator
cuff tear or a bony defect are less likely to be amenable to
nonoperative management. Misamore evaluated nonoperative treatment of
multi-directional instability and found that patients who were likely
to improve with therapy did so within 3 months of initiating a therapy
program. Patients who had unilateral symptoms, symptoms with activities
of daily living, and high grades of laxity were likely to fail
conservative treatment and require surgical intervention.¹⁸⁰
In a long-term follow-up study, Hovelius recently noted that 42% of
patients treated with therapy had no recurrent instability, whereas an
additional 7% had only one additional dislocation.⁹⁹

The procedure begins with an arthroscopic examination of
the entire joint to clearly identify the structural defects.
Significant bony defects in the glenoid or the humeral head must be
documented, as their presence may require conversion to an open
procedure. According to some studies, a glenoid defect greater than 21%
to 30% of the surface area or a Hill-Sachs defect that engages the
anterior glenoid rim with abduction and external rotation is associated
with a high likelihood of recurrent instability.³⁰,¹¹⁴,¹²⁹
In addition, the labrum must be carefully examined for any damage, and
the capsule should be assessed for redundancy and notable defects. Some
surgeons have utilized the “drive thru” sign to describe a loose joint.²⁰⁶,²⁰⁹
This sign is positive if the arthroscope can be easily passed from the
posterior portal, through the joint, into the anteroinferior quadrant.
Unfortunately, although this sign is associated with shoulder laxity,
it is not specific for shoulder instability and its accuracy for
diagnosing shoulder instability is less than 50%.¹⁶⁶
Upon completion of the diagnostic arthroscopy, the necessary portals
are established. Although surgical techniques vary among surgeons, most
tend to utilize the posterior portal for the arthroscope and anterior
portals for the instruments. If an anteroinferior capsulolabral lesion,
also known as the “Bankart” lesion, is identified, the defect must be
repaired (Fig. 38-31A). The medially displaced labrum should be mobilized and reattached to the glenoid rim in its anatomic position (Fig. 38-31B,C). This surgery is often referred to as the arthroscopic Bankart procedure.

Early arthroscopic techniques utilized a metallic staple
to reattach the labrum. Unfortunately, this technique was associated
with relatively high rates of complications (12%) and recurrent
instability (33%).⁴⁸,¹²⁰,¹⁴³
Others have described an arthroscopically assisted transglenoid suture
technique to reattach the labrum. Although short-term follow-up data
indicated excellent results with this procedure in the majority of
patients, at a midterm follow-up of 2 to 8 years, the results
deteriorated with reported recurrent instability in 17% of the patients.¹⁶⁸,²⁶⁶
More recently, arthroscopic stabilization techniques have utilized
suture anchors that can be placed at the anterior glenoid rim. These
anchors provide a stable base to reattach the capsulolabral complex.
Using suture anchors to address an isolated an anterior labral lesion
and mild capsular redundancy, various authors have reported good to
excellent results in the vast majority of patients, including those
with a “high demand” shoulder such as collegiate and professional
overhead athletes.³⁴,⁵³,¹³⁰,²¹⁴,²²²
With relatively short-term follow-up, these studies also reported very
low rates of recurrent instability between 0% and 10% for most patients
and 12.5% to 16.5% for high-demand “collision” athletes.³⁴,⁵³,¹³⁰,¹⁶⁴,²⁶⁵,³⁵⁵ At mid-term follow-up of 2 to 6 years, the rate of recurrent instability was still only 4% to 7%.¹²⁹,¹⁴⁴,²³⁰
Negative prognostic factors for arthroscopic anterior stabilization
include bone loss, inferior laxity or multidirectional instability, and
total number of anchors used in the repair being less than four.²⁰

In addition to the repair of the torn labrum, if
associated defects are noted in the capsule or the humeral attachments
of the ligaments, they must also be repaired as well. A midsubstance
tear in the capsule can occur in up to 4% of the cases and require an
anatomic repair for optimal results.¹⁸²,²²⁶
Similar to the midsubstance tears, HAGL lesions can occur in 1% to 9%
of cases of recurrent shoulder instability and may be the defect
responsible for persistent instability after surgical stabilization.²⁸,²⁶⁴,²⁸⁹

Although most surgeons would prefer repairing this defect using an open
technique, some authors have described an arthroscopic repair of the
lesion with early favorable outcome.¹³⁷,²²⁸,²⁵³

With advancing technology and expertise in arthroscopy,
a number of surgeons have recently reported on their experience
performing arthroscopic surgeries on shoulders that were traditionally
addressed with open techniques. As such, patients who have previously
failed a surgical procedure have been stabilized with arthroscopic
methods with reasonable outcomes.²²,¹⁸⁹ Arthroscopic techniques have also been used to repair anterior glenoid bone defects associated with “bony Bankart” lesions.²⁵⁸

In addition to the capsule and the labrum, the rotator
interval must also be scrutinized during any stabilization procedure.
Biomechanical studies have demonstrated that these structures
contribute to the stability of the humeral head against posterior
translation, inferior translation, and excessive external rotation.¹³,²¹²,²⁷⁷,²⁹¹ In addition, thermal shrinkage of the interval tissue has been shown to decrease anterior translation of the humeral head.²⁴⁹ Thus, defects within the rotator interval may contribute to instability in multiple directions.⁵⁹,¹⁹⁵ Several surgeons have described arthroscopic techniques for the evaluation and imbrication of the rotator interval tissue.⁶⁹,¹²⁶,²¹²,²⁷⁰
For patients with clinical or arthroscopic findings consistent with an
interval defect, the rotator interval tissue should be imbricated. This
should be performed at least 1 cm lateral to theglenoid surface in
order to avoid tethering the coracohumeral ligament that can result in
loss of external rotation.²¹² In
patients who continue to demonstrate symptoms consistent with
instability without a prior dislocation, isolated interval closure may
lead to good and excellent outcomes.⁵⁹
In the majority of the patients, however, rotator interval closure
represents a supplemental stabilization technique that is performed in
conjunction with repair of other lesions.²⁹¹

Arthroscopic capsulorrhaphy can be quite cumbersome and
requires significant surgical expertise. In order to simplify the
procedure, an arthroscopic technique called thermal capsulorrhaphy was
developed. By applying a source of heat, from either a laser or a
radiofrequency probe, the capsular tissue can be caused to contract.⁵⁴,²⁶¹ The end result of the process is to decrease capsular redundancy, decrease joint volume, and reduce glenohumeral translation.²⁷⁴
Initial enthusiasm for thermal capsular shrinkage was due, in part, to
the fact that the technology can be applied to all parts of the
glenohumeral capsule and required less surgical expertise than other
arthroscopic procedures. Hence even surgeons without extensive
arthroscopic experience were able to use this technology to treat
patients with shoulder instability. Unfortunately, however, the
procedure has been associated with unpredictable outcomes.¹⁷⁸ Some authors have reported good to excellent clinical outcomes after a relatively short follow-up period.¹⁸¹,²²³ Even for overhead athletes, good to excellent results were obtained in 88% of

the patients.²²³ In contrast, other authors have reported clearly inferior results with recurrent instability in 24% to 47% of the patients.⁴³,⁸⁸,¹⁷⁹,²⁰⁷ According to one prospective study, an unsatisfactory outcome was documented in 37% of the patients.⁴³ In addition, anatomic studies have raised concerns regarding possible thermal damage to the nearby axillary nerve.⁸⁰,¹⁶⁵
Clinical studies have substantiated these concerns. In one study
axillary nerve neuropathy was observed in 21% of the patients who were
treated with thermal capsulorrhaphy.¹⁷⁹ In addition, significant capsular thinning or necrosis may also result, requiring soft tissue grafting.³,¹⁷⁸,²⁰⁷ Other noteworthy complications of this procedure include excessive stiffness as well as extensive chondrolysis (Fig. 38-32).³⁸,⁸⁸,¹¹⁷,¹⁵¹,¹⁷⁹
Because of these issues, thermal capsulorrhaphy has experienced a
significant decline in popularity. Thus, although this technology may
play a role in augmenting other stabilization constructs, most authors
do not recommend its use as the primary procedure for shoulder
stabilization.⁸⁸

Among the numerous techniques that have been described
to treat patients with anterior glenohumeral instability, the open
Bankart procedure is perhaps the most commonly performed surgery. In
this procedure, the anterior labral defect is identified, mobilized,
and then reattached to its original anatomic site on the anterior
inferior glenoid rim.¹¹,¹²
Reattachment of the labrum to the glenoid rim can be achieved using a
number of different methods. In the original description by Bankart,
drill holes in the glenoid were utilized. He reported no recurrent
dislocations in 27 consecutive patients who were treated with this
technique.¹² Other authors,
utilizing the same technique, were also able to duplicate this success.
The reported rate of recurrent dislocation after this procedure is
roughly 2% with good to excellent results in the vast majority of
patients.¹⁰³,²²⁵
Recently, instead of drill holes, surgeons have utilized suture anchors
to reattach the labrum. Using this technique, good to excellent results
have been reported in 88% to 94% of the patients, with recurrent
dislocations in only 0% to 9.7% of the patients at short- to midterm
follow-up.^* With a long-term follow-up at 29 years,
recurrent instability rate after this procedure was still low at 10%.
Joint arthrosis was noted in surprisingly high 40% of the patients, but
symptomatic in only 16.6% of the patients. Overall, despite the joint
arthrosis, 100% of patients were satisfied with the surgery.²⁰⁸

In addition to the repair of the labrum, some authors
have also recommended reduction of the capsular redundancy. Termed the
“capsulolabral reconstruction,” this technique utilizes a similar
surgical approach to correct the pathoanatomic changes in both the
labrum and the capsule.¹¹⁸,¹⁴⁰,¹⁸³ After

standard anterior exposure, the capsule is isolated from the
subscapularis. At this point a “T”-shaped incision is made on the
capsule which includes both a horizontal and a vertical incision (Fig. 38-33).
The vertical incision can be placed laterally near the humeral head or
medially next to the glenoid rim depending on the specific technique to
be performed. With the additional horizontal incision, two separate
flaps of capsule, one superior and one inferior, are created. If a
labral defect is present, it is repaired as described previously. The
two flaps of the capsule are then imbricated onto each other by
shifting the inferior flap superiorly and the superior flap inferiorly.
In this fashion, parts of the capsule are overlapped on each other, and
the overall capsular volume can be significantly reduced. It should be
emphasized that the capsular plication is performed only to remove the
redundancy in the tissue. Excessive anterior capsular tightening can
alter the biomechanical characteristics of the joint, including
increased posterior humeral head translation and increased joint
contact forces with arm elevation, which in turn may lead to premature
joint arthrosis.²⁷⁵ Using this
technique, various authors have reported good to excellent outcomes in
the vast majority of patients with extremely low rates of recurrent
dislocation. Even in patients with high functional demands, this
procedure has been associated with good to excellent results in 92% to
96% of the patients, with recurrent dislocation in only 0% to 4% of the
patients.¹¹⁸,¹²¹,¹⁸³,²⁰⁵

For the capsulolabral reconstruction, the primary focus
is to restore the normal anatomy of the capsulolabral complex. The
subscapularis tendon is not imbricated during the procedure because it
is not a part of the pathoanatomy. Rather, it is usually repaired back
to its original length. In the Putti-Platt procedure, however, the
capsular defects are essentially ignored. Rather, the primary focus is
shifted to the subscapularis tendon, as it is divided at its midpoint
and imbricated upon itself.²⁰⁰ After
making a vertical incision 2 to 3 centimeters medial to the lesser
tuberosity, the lateral stump of the tendon is fixed to the glenoid rim
with sutures around the capsule and the labrum. The medial stump is
then laid on top and repaired to the lateral stump. In this fashion,
the subscapularis tendon is significantly shortened, and the amount of
external rotation is greatly reduced. Compared with the Bankart and the
capsulolabral reconstruction procedures, results after the Putti-Platt
procedure appear to be clearly inferior. As such, good to excellent
results were found in only 55% to 85% of the patients, and recurrent
instability was observed in 9% and 35% of the patients.⁶³,¹³⁵,¹³⁸,²⁹⁴ This procedure is also associated with loss of shoulder strength and motion.⁶³,¹³⁵,²⁷³,²⁹⁴
Although loss of external rotation can exceed 40 degrees in some
patients, most studies have reported an average loss of 9 to 23 degrees.⁴¹,¹³⁵,²⁷³,²⁹⁴
Finally, long-term follow-up of patients who underwent the Putti-Platt
procedure demonstrated a high incidence of progressive and symptomatic
glenohumeral arthritis (Fig. 38-34). According
to several studies, mild to moderate osteoarthritis was seen in 26% to
30% of the patients, and the severity of the arthritis correlated
directly to the duration of follow up.¹,¹³⁵,²⁷³
It has been suggested that the development of arthritis is related to
the loss of external rotation and posterior subluxation secondary to
overtightening of the anterior shoulder structures. Nonetheless, a
recent study of patients who had the Putti-Platt procedure also showed
that shoulders without a significant loss of motion can still develop
symptomatic joint arthrosis.⁸⁶

Another technique that alters the normal anatomy of the subscapularis tendon is the Magnuson-Stack procedure.¹⁵⁷
In this procedure, the insertion of the subscapularis tendon is
transferred from the lesser tuberosity to a position that is lateral to
the bicipital groove. With this technique, the primary goal

is
to create a tight anterior soft tissue sling that will support the
humeral head against anterior translation. Proponents of this procedure
demonstrate that good to excellent results can be obtained in 90% to
97% of the patients, with low rates of recurrent dislocations.²,⁸⁹,¹⁷⁵ Even with long-term follow-up, reported rates of recurrent instability have been less than 5%.¹²⁵,²³⁴
Although these results are impressive, nonphysiological means of
shoulder reconstructions have generally fallen into disfavor since they
alter the normal biomechanics of the glenohumeral joint and do not
directly address the underlying pathoanatomy. As expected, the
Magnuson-Stack procedure is associated with a loss of external rotation
and forward elevation. In comparison with the patients who underwent
the Putti-Platt procedure, however, this loss was fairly minimal at 5
to 10 degrees.²²¹,²³⁴
Other reported complications of the procedure include excessive
anterior tightening with posterior glenohumeral subluxation, damage to
the biceps tendon, and early joint arthrosis.¹,⁷⁷,⁸⁶

In addition to the soft tissue techniques, a number of
different bony procedures have been described to treat patients with
anterior glenohumeral instability. Defects greater than 30% of the
glenoid surface may be associated with persistent instability.¹¹⁴,¹⁸⁴
Therefore, if these defects are present, they can be addressed by
placing a piece of bone on the glenoid neck in order to provide an
additional surface to interact against the humeral head and to act as a
buttress against anterior dislocation. Even without a glenoid bone
defect, however, surgeons have utilized various bony procedures to
stabilize the glenohumeral joint with varying degrees of success.

Because of its nearby location, the coracoid process has
been utilized in two of the more commonly performed bony procedures.
The first is the Bristow procedure in which the tip of the coracoid
process, with the conjoined tendons attached, is transferred through a
split in the subscapularis muscle and fixed onto the anterior inferior
glenoid rim just outside the capsule.⁹⁰ A subsequent modification of the procedure transfers the coracoid process over the superior border of the subscapularis tendon.²⁶⁷
Usually, the rim of the glenoid is exposed and decorticated in order to
enhance bony union between the cut surface of the coracoid process and
the glenoid rim. Because of the remaining capsule, however, some
portion of the transferred bone will not directly interact with the
exposed glenoid rim. Patient satisfaction rate at early and midterm
follow up after this procedure has been reported to be between 82% and
97%.¹⁰,⁵⁸,²⁶⁷ Recurrent dislocations after the procedure were very uncommon, with the reported incidence between 0% and 6%.⁵⁸,⁹⁶,¹⁵⁶,²⁶⁷ If episodes of subluxations are also included, however, the rate of recurrent instability is much higher at 8.5% to 21%.¹⁰,⁵⁸,⁹⁶,²⁶⁷
With an extended long-term follow up of 26 years, one study has
demonstrated that both patient satisfaction and joint stability
deteriorated to 70% and 85%, respectively.²⁴⁵
In addition, the Bristow procedure is also associated with high rates
of complications that include loss of external rotation, problems
related to the screw fixation, residual pain, and graft nonunion.⁵⁸,²⁶⁷ In fact, the rate of screw-related complications was reported to be as high as 24% in one study.¹⁹⁴
Because of these concerns, some authors have recommended that the
Bristow procedure not be performed for routine anterior stabilization
of the shoulder.²⁴⁵,²⁹³

Another bony procedure that utilizes the coracoid
process is the Latarjet procedure. In comparison with the Bristow
procedure, a significantly larger portion of the coracoid process is
transferred to the neck of the glenoid. The bone is placed in an
extracapsular position, laid on its side, and fixed to the scapula with
screws. At a long-term follow-up evaluation, good to excellent clinical
results were found in 88% to 93% of the patients who were treated with
this procedure.⁴,²⁵² Rates of recurrent instability, including both subluxation and dislocation, have been reported to be between 2% to 10%.⁴,¹⁰⁰ Ninetyeight percent patient satisfaction has been described at 15-year follow-up.¹⁰²
Despite these clinical results, however, the procedure is also
associated with the subsequent development of joint arthrosis. Although
the majority of the changes were classified as mild, glenohumeral
arthrosis was reported in 30% to 71% of the patients.⁴,¹⁰⁰,¹⁰¹ In one study, moderate to severe arthrosis was described in 14% of patients with a Latarjet procedure at 15-year follow-up.¹⁰¹

Another of the more commonly used bony procedures is the Eden-Hybbinette procedure.⁵⁰,¹⁰⁹
The original description as well as the modification of the procedure
places an iliac crest bone graft on the anterior aspect of the glenoid.
Therefore, the humeral head must translate further to dislocate.
Long-term studies of this procedure have shown good to excellent
results in 75% to 85% of the patients.²⁷,²¹⁷,²¹⁸ Reported rates of recurrent dislocations have been mixed, with some authors reporting only 4% and others reporting up to 33%.²⁷,¹³⁸,²¹⁸
Unfortunately, after long-term follow-up evaluation in excess of 15
years, several authors have reported joint arthrosis in 47% to 89% of
the patients.²¹⁷,²¹⁸
Thus the Eden-Hybbinette procedure has lost much of its popularity as a
primary procedure for routine anterior shoulder stabilization.

In contrast to these procedures that place the bone
outside the joint, another option is to place the bone graft within the
joint. Intra-articular bone grafts are typically inserted to restore,
rather than to enlarge, the glenoid surface. Although individual
techniques can vary, most surgeons place the bone against decorticated
glenoid neck and then fix the graft using several metallic screws. The
fixed graft is subsequently contoured to match the surface of the
native glenoid. Finally, the anterior capsule and the subscapularis
tendon are restored to their anatomic position. A limited series of
patients treated in this fashion demonstrated good results with absence
of apprehension and return to preinjury level of athletic activities.
The authors noted that intra-articular placement of grafts improved the
likelihood of graft union as well as allowing improved matching of the
glenoid surface.²⁷⁸ Hence, although
long-term clinical data are still lacking, this technique may provide a
promising alternative to addressing symptomatic glenoid bony defects.

Isolated posterior instability is relatively rare and thought to comprise 2% to 12% of all shoulder instability cases.²¹,²⁴
As such, the clinical history and examination must be thoroughly
reviewed in order to ensure that the instability is isolated to the
posterior direction only. For these patients, indications for surgery
include failure of nonoperative management, open dislocations,
irreducible dislocations, and unstable reductions. In some patients,
traumatic posterior dislocations may be associated

with
a large bony defect in either the glenoid or the anteromedial humeral
head (reverse Hill-Sachs lesion). With these defects, even after a
concentric reduction is obtained, joint stability may be compromised
enough to warrant operative management.

Once the decision to proceed with an operation has been
established, there are multiple available surgical options. Surgical
stabilization may be performed arthroscopically, through an open
anterior approach, or through an open posterior approach. To date, no
single approach or technique has been associated with conclusively
superior results. As such, the choice of any specific procedure should
be based on patient expectations as well as surgeon-related factors
such as familiarity, technical expertise, and available equipment and
personnel.

The procedure starts with a diagnostic arthroscopy to
identify and document any structural defects. Although specific
protocols may vary among surgeons, most utilize an anterior portal for
the arthroscope and two posterior portals for the instruments. If a
posterior capsulolabral detachment is identified, it should be
mobilized and reattached to the posterior glenoid rim. Recently use of
suture anchors has become the technique of choice for capsulolabral
reattachment. Unlike anterior instability, however, a posterior
capsulolabral detachment is a much less common finding. For posterior
instability, capsular redundancy seems to play a more critical role. As
such, this redundancy should be addressed by performing arthroscopic
posterior capsulorrhaphy.²¹

Using this arthroscopic technique, authors have reported
good to excellent results in 86% to 96% of the patients at shortto
midterm follow up.¹³¹,²⁸¹,²⁸⁸ Rates of recurrent instability in these studies have ranged from 0% to 12%.²¹,²⁴,⁷⁵,¹³¹,²¹⁶,²⁸¹
One recent study confirmed that frank posterior dislocations after
surgery were very rare; however, clinically significant posterior
subluxations may be more common. In this study 11% of the patients
failed clinical stability tests and 8% pursued revision surgery for
persisting pain, instability, or decreased function.²⁴

Similar to anterior and multidirectional instability,
some authors have recommended the use of thermal capsulorrhaphy to
reduce posterior capsular redundancy. As mentioned previously, however,
this technology may be associated with unacceptable risks for clinical
failures and complications, frequently resulting in persisting pain,
instability, and damaged capsular tissue. As such, routine use of this
technique as a primary stabilizing procedure has fallen into disfavor.

In selective patients with atraumatic glenohumeral
instability whose primary complaint is in the posterior direction, an
anterior approach for posterior shoulder stabilization has been
described.²⁸⁵,²⁸⁶
This procedure is performed in a manner similar to the inferior
capsular shift procedure for patients with multidirectional
instability. The anterior deltopectoral approach is utilized to expose
the shoulder. After releasing the subscapularis tendon and isolating
the capsule, the capsule is released from the humeral neck as far
posteriorly as possible. The capsule is then advanced anteriorly and
superiorly in order to remove the redundancy in the anterior, inferior,
and posteroinferior aspects of the joint. In addition to the capsular
imbrication, the anterior approach also provides an opportunity to
address the concomitant laxity in the rotator interval. In this
fashion, humeral head translation is reduced in all directions. At a
midterm follow up of 5 years, a case series reported good to excellent
results in 9 of the 10 patients who were treated with this technique.²⁸⁵

Following a traumatic posterior dislocation, a large
bony defect in the anterior aspect of the humeral head (also known as
the reverse Hill-Sachs lesion) may be present. If the defect is large,
it may engage the posterior glenoid rim during internal rotation,
resulting in recurrent episodes of instability. Therefore although an
anatomic joint reduction can be initially obtained, stable and
congruent motion may not be maintained. For these patients, the bony
defect is the primary pathology and it can be addressed with the
McLaughlin procedure (Fig. 38-35A). The
original description of the procedure includes an anterior approach
with release of the subscapularis tendon from the lesser tuberosity.
The released tendon is then transferred into the bony lesion to fill
the defect and to prevent the humeral head from engaging the posterior
glenoid rim.¹⁷⁰ A modification of this procedure, described by Neer (Fig. 38-35B),
does not release the subscapularis tendon. Rather, the lesser
tuberosity is osteotomized with the attached tendon so that it can be
transferred into the bony defect.⁶⁰,²⁸⁶
Although similarly filling the defect, this modification creates a more
stable construct with improved potential for healing. Although only a
few studies

have
been published, authors have reported stable shoulders with congruent
motion in the majority of patients who were treated with this operation.⁶⁰,¹⁷⁰

For patients with unidirectional posterior instability
or for those with multidirectional instability whose primary symptoms
are in the posterior direction, a posterior approach to the shoulder
can be utilized. Upon exposure of the joint, if a clear capsulolabral
detachment is present, it should be repaired. In addition, posterior
capsular redundancy is addressed by performing posterior capsulorrhaphy
in a manner similar to anterior capsulorrhaphy. For these procedures
meticulous surgical technique must be utilized, because the posterior
capsule is often very thin and fragile.

Some authors advocate posterior capsulorrhaphy using
metallic staples for fixation. According to one series, however,
unsatisfactory results were reported in 9 of the 20 (45%) patients.²⁶³
The authors suggested that the high rate of failures may be related to
general ligamentous laxity and unrecognized multidirectional
instability.²⁶³ Regardless, the use of a staple has been abandoned in favor of suture capsulorrhaphy.²⁶³
Results following posterior suture capsulorrhaphy are more encouraging.
Studies have reported good to excellent results in 80% to 92% of the
patients who were treated with this procedure. Rates of recurrent
instability have been reported to be between 11% and 23% in these
studies.¹⁶,⁶⁴,²²⁷

Several authors have suggested that patients with
recurrent posterior instability may possess excessive glenoid
retroversion, and that this retroversion may be responsible for the
high rates of surgical failures.⁶⁴,¹⁰⁶,¹³²,²⁸⁷
If excessive retroversion (e.g., greater than 30 degrees) does exist,
normal glenoid version can be restored by performing a posterior
glenoid osteotomy. This procedure utilizes a similar surgical approach
as described above. After exposing the joint, an opening wedge
osteotomy is performed at the posterior scapular neck. The opening
wedge can be stabilized with a bone graft from either the iliac crest
or the posterior acromion. Surgical exposure of the scapular neck must
be performed with caution as the suprascapular nerve lies in close
proximity and is susceptible to injury during the procedure.

Case reports of glenoid osteotomy have mostly produced satisfactory results.¹⁵,
287 A recent report of 32 patients who were treated with this procedure
also noted good to excellent results in 82% of the patients.⁷⁶ Rates of recurrent instability after the procedure have been reported to be between 12% and 17%.⁷⁶,⁸⁵
Unfortunately, however, this procedure is also associated with a
variety of complications including anterior subluxation, coracoid
impingement, glenohumeral arthrosis, and intra-articular glenoid
fracture.⁶⁴,⁷⁰,⁷⁶,⁸⁵
Therefore some authors have suggested that the procedure be performed
only in patients whose glenoid shows significant retroversion in excess
of 30 degrees.²⁸⁶

Multidirectional instability of the shoulder is often a
difficult diagnosis to establish. In many instances, patients exhibit
signs of generalized ligamentous laxity and the onset of their shoulder
symptoms are not preceded by significant trauma. In other instances,
however, patients exhibit signs of generalized ligamentous laxity but
sustain an injury that produces unidirectional instability. As such, it
is difficult to determine whether these patients should be categorized
and treated in a manner similar to unidirectional or multidirectional
instability. These nuances in establishing a clear diagnosis have
contributed to the lack of a true consensus for surgical management of
these patients. Most surgeons do agree, however, that the primary
treatment for patients with atraumatic multidirectional instability
should be nonoperative, with a primary focus on shoulder
rehabilitation. Strengthening of the dynamic shoulder stabilizers has
the potential to compensate for the generalized laxity of the static
shoulder stabilizers. Operative treatment for these patients is
indicated only when nonoperative management has been unsuccessful.
Although the specific indications may vary among surgeons, operative
management is generally recommended for patients who suffer from
continued pain and/or disability despite participation in a structured
physical rehabilitation program for greater than 3 to 6 months.

Once the decision for an operative stabilization has
been established, the procedure may be performed arthroscopically or as
an open procedure. For open procedures, some surgeons preferentially
utilize an anterior approach, whereas others utilize either an anterior
or a posterior approach based on the primary direction of instability.
The “gold standard” for surgical management of multidirectional
instability has been the open stabilization. With recent technological
advances, results after arthroscopic stabilizations are clearly
improving. A recent study of arthroscopic capsulorrhaphy demonstrated a
fairly low rate of instability at 10.5%.¹⁶⁰
Nevertheless, to date, long-term outcome studies after arthroscopic
techniques are still lacking and have yet to replicate those of open
surgery (Table 38-4).^*

After performing an examination under anesthesia to
confirm the diagnosis, a diagnostic arthroscopy is performed to
document the pathology. In the vast majority of patients with
atraumatic multidirectional instability, a clear capsulolabral
detachment is not present. The most common finding is the presence of
redundant capsule in the anterior, inferior, and posterior aspects of
the joint, all of which must be addressed. For arthroscopic
capsulorrhaphy in the anterior region, the arthroscope is typically
placed through a posterior portal whereas the instruments and the
sutures are managed through anterior portals. In contrast, for
posterior capsulorrhaphy, the arthroscope is placed through the
anterior portal whereas the instruments and the sutures are managed
through posterior portals. Again, the capsulorrhaphy typically starts
in the inferiormost aspect of the joint and progresses superiorly until
the redundancy in the capsule has been sufficiently removed.

According to one study, arthroscopic capsulorrhaphy
using transglenoid suture technique has been associated with 88% good
to excellent results and 12% recurrent instability.²⁷¹
Subsequently, surgeons have slightly modified the technique to perform
the entire capsulorrhaphy using suture tying techniques. With a
relatively short follow up of approximately 3 years, two studies have
reported good to excellent results in 94% to 95%

of the patients. In addition, they reported very low rates of recurrent instability at 2% to 5%.⁶⁸,¹⁶⁹
Mid- and long-term follow-up studies of this technique, however, are
still lacking. Rotator interval closure may be added to capsular
plication in the setting of multidirectional instability in order to
further limit humeral head translation.

Another arthroscopic technique that has been utilized to
treat patients with multidirectional instability is thermal
capsulorrhaphy. As noted in the previous sections, outcomes after this
procedure have been mixed. Various studies have reported recurrent
instability in 19% to 47% of the patients.⁴³,⁵⁶,⁶¹,¹⁷⁹
In addition to these high rates of recurrent instability, this
procedure has also been associated with high rates of complications.
Therefore, routine use of this technique for patients with
multidirectional instability has fallen into disfavor.

Some authors treat all patients with multidirectional
instability through an open anterior approach. This procedure is
performed in a manner similar to open anterior capsulolabral
reconstruction, as described in the previous section. The primary
difference, however, is the focus on the inferior aspect of the
shoulder capsule. As such, inferior capsular redundancy must be
addressed by first releasing the capsule from the humeral neck all the
way to the posterior inferior quadrant of the joint. The released
capsule is then advanced anteriorly and superiorly to remove the global
capsular redundancy. The original description of this inferior capsular
shift procedure was reported by Neer et al.¹⁸⁷
In their preliminary series, satisfactory results were reported in 39
of the 40 patients, with only one patient developing recurrent
instability. Several subsequent studies have reported comparable
results with good to excellent results in over 90% and recurrent
instability in less than 10% of the patients.⁹,⁴²
In one report, the authors also noted that the failures occurred early
and that the overall outcomes did not deteriorate over time.⁴²
Biomechanical analysis of the inferior capsular shift demonstrated that
glenohumeral mechanics and contact pressures did not change
significantly, compared with normal joints.²⁷⁵,²⁸⁰ Therefore, even with long-term follow-up, development of glenohumeral arthrosis will hopefully remain minimal.

Rather than utilizing an anterior approach in all
patients, some surgeons recommend approaching the shoulder from the
direction of primary instability. As such, if a patient exhibits signs
of multidirectional instability but has a primary complaint of
posterior instability, a posterior approach is suggested. A posterior
capsular shift procedure is performed as described previously. Again,
particular attention should be given to the inferior capsule in order
to remove the global capsular redundancy. Utilizing either an anterior
or a posterior approach based on the direction of primary instability,
authors have reported good to excellent results in 85% to 94% of the
patients.³⁵,⁸³,²¹³
Although the rate of recurrent instability was relatively low in two of
these studies (4% to 9%), one study reported recurrent instability in
26% of the patients.⁸³ These authors
also showed that the recurrent instability tended to occur early and
that the successful results were maintained over time.⁸³

Patients with a chronic shoulder dislocation usually
report a history of traumatic incident. The trauma may involve fall
from a height, motor vehicle accident, or less commonly, electrical
shock or seizure episodes. These accidents cause an acute shoulder
dislocation which is associated with significant pain. In most
patients, this pain is sufficient enough to seek immediate medical
attention. Chronic shoulder dislocations occur in situations when the
initial dislocation was unappreciated or when the patient did not or
could not seek adequate medical care. As such, chronic dislocations may
be observed in patients with extremely high tolerance of pain, patients
with decreased mental ability to recognize or verbalize their pain, and
patients with additional injuries that are more obvious or
life-threatening.

Several weeks after the injury, shoulder pain and edema
will start to dissipate. With the resolution of symptoms, patients may
start using their arm at waist level for functional activities. This
improvement can often be mistaken as the initial step in their
recovery. Despite these improvements, however, shoulder motion will
continue to be limited. Patients with an anterior dislocation typically
lack internal rotation and abduction, whereas those with a posterior
dislocation often lack external rotation and abduction. If the humeral
head remains engaged on the glenoid rim, shoulder motion will often be
associated with a mechanical block as well as crepitus. Because of this
limitation in motion, these patients can be misdiagnosed as having a
posttraumatic adhesive capsulitis or a “frozen shoulder.”⁸⁷,²⁴⁶ As the improvement in shoulder function reaches a plateau, a more serious injury is eventually suspected.

Patients with a chronic shoulder dislocation can suffer
from varying degrees of pain. Thus, some patients may report
surprisingly little pain whereas others will complain of excruciating
pain. In addition, their functional capacity can also vary widely with
some patients reporting fairly reasonable use of their arm, especially
at waist level. As a general group, however, these patients suffer from
significant shoulder dysfunction. Perhaps the most consistent of their
symptoms include stiffness, crepitus, deformity, and failure to use the
arm for overhead activities.

Management of a chronic shoulder dislocation remains a
challenge. Primary goals of treatment are satisfactory pain relief and
optimization of functional recovery. It is crucial for the surgeon to
establish reasonable expectations for the treatment. This information
must be thoroughly discussed with the patient and family. Desire to
perform aggressive, and often technically demanding, interventions
should be tempered by the patient’s expectations, general health,
anticipated functional recovery, and ability to participate in
postoperative rehabilitation.

Nonoperative treatment of chronic shoulder dislocations
may be appropriate for patients with minimal pain and disability.
Following the resolution of pain from the initial injury, elderly
patients with a low functional demand may demonstrate excellent
adaptation. With a functional contralateral upper extremity, these
patients may be able to perform activities of daily living despite
limitations in their shoulders. Nonoperative management may also be
desirable for patients with an unacceptably high medical risk for
surgery, patients with an uncontrollable seizure disorder, and patients
who are physically or mentally unable to comply with postoperative
instructions and rehabilitation. For these patients, initial treatments
should concentrate on supportive care. As such, they should undergo a
brief period of immobilization. Once they recover from the initial
injury, gradual rehabilitation that focuses on the restoration of
function should be instituted. As such, active assisted and active
motion exercises should be augmented with occupational therapy that
emphasizes activities of daily living. Aggressive passive stretching
exercises should be avoided as they can lead to further injuries.

Most outcome studies of nonoperative treatment for
chronic shoulder dislocations contain a small number of patients. As
such, firm conclusions are difficult to establish. In general, however,
these studies show that rarely is enough motion regained for overhead
activities.⁷⁴,⁸⁷,¹⁷⁰
Patients with a chronic posterior dislocation appear to have a more
favorable outcome than those with a chronic anterior dislocation.
Because of these findings, it must be stressed to the patient that the
treatment is based on achieving “limited goal” outcomes with tolerable
pain and function. As such, unrealistic patient expectations for a
normal shoulder must be addressed prior to the initiation of any
treatment.

Surgical management of a chronic shoulder dislocation
can vary widely. The choice to proceed with any specific procedure is
dependent on multiple factors including the chronicity of the injury,
associated bony injuries, and associated soft tissue injuries. Other
patient-related factors such as age, hand dominance, vocational
requirements, and medical comorbidities also play a significant role.
Because of this variability, no single procedure has been
preferentially used to treat patients with a chronic shoulder
dislocation.

The primary goal of surgery is a concentric and stable
joint. An attempt at closed reduction, even under general anesthesia,
is unlikely to be successful.⁷⁴,²⁴⁶
If the joint cannot be reduced, an open surgical reduction can then be
performed. In most situations, the deltopectoral interval is used for
an anterior approach to the shoulder. After exploration of the joint
and removal of any interposed tissues, the humeral head is reduced back
onto the glenoid. Because of soft tissue contractures, joint reduction
may not be stable. In these situations, appropriate soft tissue
releases must be performed. In a classic article by Rowe and Zarins,
appropriate soft tissue release and postoperative immobilization were
sufficient to maintain concentric shoulder reduction.²³⁸
For patients with chronic anterior dislocations, the arm was
immobilized anterior to the coronal plane of the body after the
surgical reduction. Conversely, for patients with chronic posterior
dislocations, the arm was immobilized posterior to the coronal plane of
the body. Of the seven shoulders that were treated in this fashion,
they observed good to excellent results in five shoulders and fair
results in two shoulders.²³⁸

Other authors, however, have recommended the use of supplemental fixation to maintain postoperative joint reduction.⁷⁴,¹⁹⁰,²⁸³ In a recent report of 10 patients with a chronic shoulder

dislocation, the shoulders were surgically reduced and then fixed with
percutaneously placed Kirschner wires through the acromion into the
humeral head. This construct was augmented with a Bristow procedure in
all patients. The Kirschner wires were left in place for 4 weeks during
which the patients were immobilized in a body bandage. At a follow up
of greater than 2 years, the author reported stable joint reductions in
all patients with a good to excellent clinical result in 8 of the 10
patients.⁷⁴

If chronic shoulder dislocation is associated with a
significant bony injury, the defect may need to be surgically
addressed. Based on the location and the size of the defect, a number
of different procedures may be considered. They include the McLaughlin
procedure, disimpaction and bone grafting, and resection arthroplasty.⁸⁷,¹²³,¹⁹⁰,²³⁸ If degenerative changes are present within the joint, shoulder replacement surgery can also be considered (Fig. 38-39).
Unfortunately, to date, no single procedure has clearly demonstrated a
superior outcome compared to others for the chronically dislocated
shoulder.