finnoff glenohumeral instdsability and dislocation.pdf

Phys Med Rehabil Clin N Am

15 (2004) 575–605

Glenohumeral instability and dislocation

Jonathan T. Finnoff, DOa,b,*,Susan Doucette, PT,MSc,Gregory Hicken, MDb

aDepartment of Health, Physical Education and Recreation,

Utah State University, Logan, UT 84341, USAbAlpine Orthopedic Specialists, 2380 North 400 East, Suite A,

North Logan, UT 84341, USAcLogan Physical Therapy, 550 East 1400 North, Suite M, Logan, UT 84341, USA

Glenohumeral joint instability is a common disorder of the shoulder. Theglenohumeral joint is the most mobile joint in the body, and by design, it hasgained the extra mobility at the expense of stability. Instability may present ina variety of ways. Pain may be the only symptom experienced by somepatients, whereas others may present with a frank dislocation. A thoroughunderstanding of the regional anatomy and biomechanics, the pathophys-iology of glenohumeral joint instability, and the performance of anappropriate history and physical examination should lead the examiner tothe correct diagnosis. This article reviews the anatomy of the shoulder jointcomplex; discusses the complex interplay of static and dynamic structuresthat provide glenohumeral joint stability; presents a classification system forglenohumeral joint instability; discusses the pathophysiology of glenohum-eral joint instability; presents a logical approach to the history, physicalexamination, and radiologic examination for glenohumeral joint instability;and discusses the current nonoperative and operative treatment options forthis disorder.

Anatomy and biomechanics

The shoulder complex is composed of the sternoclavicular joint,acromioclavicular joint, scapulothoracic articulation, and glenohumeraljoint [1]. The glenohumeral joint, which is considered an enarthrodial joint

* Alpine Orthopedic Specialists, 2380 North 400 East, Suite A, North Logan, UT 84341,

USA.

E-mail address: [email protected] (J.T. Finnoff).

1047-9651/04/$ - see front matter � 2004 Elsevier Inc. All rights reserved.

doi:10.1016/j.pmr.2003.12.004

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576 J.T. Finnoff et al / Phys Med Rehabil Clin N Am 15 (2004) 575–605

(ball and socket), depends on static and dynamic factors for joint stability. Amore detailed description of shoulder anatomy is presented in anotherarticle elsewhere in this issue.

Static stabilizers

The static stabilizers of the glenohumeral joint include the bonycongruence of the joint surfaces, the geometry of the glenohumeral joint,the glenoid labrum, the joint capsule and ligaments, and the negative intra-articular pressure [2]. The humeral head to shaft angle is 130� to 140�, and thehumeral head is retroverted 30� relative to the elbow’s transepicondylar axis[3]. The humeral head composes approximately one third of a sphere on theproximal humerus, which equates to an arc of 120� [3]. The glenoid fossa isthe articular surface on the scapula where the humeral head articulates. Thescapula rests in a position of 30� to 45� anterior to the coronal plane, and theglenoid fossa is approximately 7� retroverted relative to the scapula with a 5�

cephalad tilt [3]. The orientation of the glenoid fossa relative to the humeralhead provides a barrier to posterior and inferior glenohumeral jointinstability [4]. Proper scapulothoracic movement is required to maintainthe appropriate glenohumeral joint orientation for static glenohumeral jointstability.

The glenoid fossa is relatively shallow and covers only about 25% of thehumeral head surface [3]. This percentage is increased to approximately35% with the addition of the glenoid labrum [3]. The glenoid labrum isa fibrocartilaginous structure that is attached firmly to the rim of the glenoidin all regions except for the superior area, where it is attached loosely. Theglenoid labrum increases the glenoid fossa depth by 50% and provides anattachment point for the glenohumeral ligaments. The forces required todislocate the humeral head are decreased by 20% after removal of theglenoid labrum, indicating that this structure has an important role asa static stabilizer of the glenohumeral joint [5].

The glenohumeral joint capsule attaches proximally to the glenoidlabrum and distally to the surgical neck of the humerus [6]. The capsule islax in the mid ranges of glenohumeral joint motion and becomes taut at theextremes of motion. The glenohumeral joint capsule acts as a static stabilizerat end ranges of glenohumeral joint motion [6].

The glenohumeral ligaments are thickenings of the glenohumeral jointcapsule and include the superior, middle, and inferior glenohumeralligaments. Another ligament involved in the static stability of theglenohumeral joint is the coracohumeral ligament. Dempster [7] hypothe-sized that the capsuloligamentous restraints of the glenohumeral joint actedin a global or ring fashion. Any translation of the humerus on the glenoidwould result in tension of the capsuloligamentous structures on the same andopposite sides of the translation. This theory has been supported by researchdesigned to identify the stabilizing role of the glenohumeral ligaments.

577J.T. Finnoff et al / Phys Med Rehabil Clin N Am 15 (2004) 575–605

The superior glenohumeral ligament is the most constant of the threeglenohumeral ligaments and provides resistance to inferior and posteriorglenohumeral instability [4,8]. The superior glenohumeral ligament resistsposterior and inferior instability most efficiently when the humerus is inadduction and external rotation [9]. The coracohumeral ligament seems tohave a similar role to the superior glenohumeral ligament in preventingposterior and inferior glenohumeral joint instability [4,9,10]. The superiorglenohumeral ligament, coracohumeral ligament, and long head of the bicepstendon all are located within the rotator interval, an area between thesupraspinatus and subscapularis tendons [11]. The middle glenohumeralligament is the least consistent of the glenohumeral ligaments and is theprimary restraint to anterior glenohumeral joint instability when the humerusis abducted to 45� [12].

The inferior glenohumeral ligament includes an anterior band anda posterior band, which are divided by a loose area of capsule referred toas the axillary pouch [13]. With the humerus in 90� of abduction, the anteriorband of the inferior glenohumeral ligament becomes the primary restraint toanterior glenohumeral instability [13]. Selective incision of the posteriorcapsule and posterior band of the inferior glenohumeral ligament results inposterior subluxation of the glenohumeral joint, but an incision of the rotatorinterval is required before full dislocation can occur [14,15]. The posteriorstabilizing effect of the inferior glenohumeral ligament’s posterior band ismost effective at 90� of humeral abduction [16]. The requirement of pathologyto the anterior and the posterior static stabilizers of the glenohumeral jointbefore full posterior dislocation serves to reinforce further the circle theory ofcapsuloligamentous glenohumeral stability.

The intact glenohumeral joint has a negative intra-articular pressurecreating a vacuum effect across the glenohumeral joint [17]. Loss of this intra-articular pressure results in inferior subluxation of the glenohumeral joint[17]. Although the vacuum-stabilizing effect of the negative intra-articularpressure is primarily a stabilizer against inferior instability, it also serves toprevent instability in all other directions [18].

Dynamic stabilizers

The dynamic stabilizers of the glenohumeral joint include the scapularstabilizing and rotator cuff muscles and the long head of the biceps [19].Dynamic stability not only depends on the sufficient strength, flexibility, andendurance of these muscles, but also appropriate proprioceptive input andneuromuscular control [20].

The importance of optimal scapular function for glenohumeral jointstability cannot be overemphasized. The scapular stabilizing muscles orientthe scapula properly in relation to the humerus for optimal static anddynamic stability of the glenohumeral joint and stabilize the scapula duringglenohumeral joint movements [21]. The scapular stabilizing muscles include


the serratus anterior, trapezius, pectoralis minor, rhomboideus minor andmajor, latissimus dorsi, and levator scapulae [21].

The rotator cuff muscles include the supraspinatus, infraspinatus,subscapularis, and teres minor. These muscles contribute to dynamicglenohumeral joint stability through many mechanisms. Concavity compres-sion, first described byLippitt et al [22], refers to the compressive forces placedon the glenohumeral joint during rotator cuff muscle cocontractions. Theseforces press the humeral head into the glenoid fossa, center the humeral headwithin the glenoid fossa, and help resist glenohumeral translation. Becausethe glenohumeral ligaments are lax in the mid ranges of glenohumeral jointmotion, coordinated rotator cuff muscle contraction and concavity compres-sion are particularly important mechanisms for glenohumeral joint stabilityin these ranges [19]. At the distal insertion of the rotator cuff muscles on thehumerus, there is an intertwining of the joint capsule with the rotator cufftendons. With rotator cuff muscle contraction, it is possible that theglenohumeral joint capsule develops tension and increases in stiffness, actingas a dynamic musculoligamentous stabilizing system [19]. The rotator cuffmuscles also provide glenohumeral joint stability through passive muscletension and act as barriers to glenohumeral joint translation during activemotion [23,24]. In particular, the subscapularis seems to be an importantstabilizer of anterior and posterior glenohumeral joint stability [14,25].

Proprioception and neuromuscular control refer to the mechanism by whichthe position and movements of the shoulder girdle are sensed (propriocep-tion), are processed, and result in an appropriate motor response (neuro-muscular control) [20]. Glenohumeral joint instability often is associated witha concomitant decrement in proprioception [26]. The abnormal propriocep-tion is restored after surgical correction of the joint instability, suggesting thatthe mechanism of proprioceptive deficits in unstable glenohumeral joints isa lack of appropriate capsuloligamentous tension [27].

Classification of glenohumeral joint instability

The classification of glenohumeral joint instability includes the degree,frequency, etiology, and direction of instability [6]. The degree includesdislocation, subluxation, and microinstability. A dislocation implies that thehumeral head is disassociated from the glenoid fossa and often requiresmanual reduction. A subluxation occurs when the humeral head translates tothe edge of the glenoid, beyond normal physiologic limits, followed by self-reduction. Microinstability is due to excessive capsular laxity, is multidirec-tional, and is associated frequently with internal impingement of the rotatorcuff [6].

The frequency of instability can be acute or chronic [6]. Acute instabilityinvolves an acute injury resulting in subluxation or dislocation of theglenohumeral joint.Chronic instability refers to repetitive instability episodes.


The etiology of glenohumeral joint instability can be traumatic oratraumatic [6]. Unidirectional instability frequently is caused by a traumaticevent resulting in disruption of the glenohumeral joint. Atraumatic instabilityrefers to glenohumeral joint instability due to congenital capsular laxity orrepetitive microtrauma. Atraumatic instability can be subclassified intovoluntary and involuntary categories. An individual who can sublux ordislocate the glenohumeral joint volitionally has voluntary instability,whereas an individual who cannot do so has involuntary instability. Somepatients with voluntary instability have associated psychological pathology,which portends a poor outcome if surgical stabilization is performed [28].

Glenohumeral joint instability can be unidirectional or multidirectional.Unidirectional instability refers to instability only in one direction. The mostfrequently occurring type of unidirectional instability is traumatic anteriorinstability [6]. Multidirectional instability is instability in two or moredirections and is usually due to congenital capsular laxity or chronic repetitivemicrotrauma [6].

Pathophysiology of glenohumeral joint instability

Glenohumeral joint instability may result from three primary etiologies:acute major trauma, chronic repetitive microtrauma, or congenital abnor-malities [10]. This section discusses common pathologic lesions associatedwith glenohumeral joint instability.

Anterior instability

Anterior instability is caused most frequently by a tear in the anterior-inferior glenohumeral joint capsule (involving the middle glenohumeralligament or anterior band of the inferior glenohumeral ligament) ordetachment of the anterior-inferior glenoid labrum from the glenoid rim[19]. The latter of these two entities frequently is referred to as aBankart lesion[29]. Bankart lesions also can involve a fracture of the anterior-inferiorglenoid rim, commonly referred to as a bony Bankart lesion [30]. Variations ofthe Bankart lesion include the Perthes lesion and the anterior labroligamen-tous periosteal sleeve avulsion lesion [30]. Other anatomic lesions thatcontribute to anterior glenohumeral joint instability include humeralavulsion of the glenohumeral ligament, superior labral anterior posteriorlesions, injury to the rotator interval, and rotator cuff tear (particularly to thesubscapularis muscle) [19]. Acute anterior glenohumeral joint dislocationsalso frequently are associated with a compression fracture of the postero-lateral aspect of the humeral head, referred to as a Hill-Sachs defect [30].

Inferior instability

Inferior glenohumeral joint instability typically does not occurin isolation. Causes of inferior glenohumeral joint instability include


capsuloligamentous laxity; absence of the glenoid fossa upward tilt; andlesions to the rotator interval, inferior glenohumeral ligament, superior gleno-humeral ligament, coracohumeral ligament, and inferior glenoid labrum.

Posterior instability

Congenital glenoid hypoplasia or excessive glenoid or humeral retrover-sion has been reported to contribute to posterior glenohumeral jointinstability. More common lesions that lead to posterior glenohumeral jointinstability include excessive capsuloligamentous laxity and injury to therotator interval, superior glenohumeral ligament, posterior band of theinferior glenohumeral ligament, coracohumeral ligament, or subscapularismuscle [10]. A tear of the posterior-inferior glenoid labrum causingseparation from the glenoid fossa rim, often referred to as a reverse Bankartlesion, or a fracture of the posterior inferior glenoid fossa rim also may causeposterior glenohumeral joint instability [10,31]. A reverse Hill-Sachs defectalso may be present, representing an impaction fracture of the anteriorhumeral head [10,31].

Multidirectional instability

Multidirectional instability may be due to primary or secondarycapsuloligamentous laxity. It frequently is seen bilaterally and may beaccompanied by generalized joint laxity [6]. Occasionally, recurrent unilateraljoint instability stretches the glenohumeral capsuloligamentous structures tothe point where multidirectional instability develops secondarily [6]. Anotherpossible cause for secondary multidirectional instability is the presence of anunderlying connective tissue disorder, such as Marfan’s or Ehlers-Danlossyndromes [6].

History

The history should include the patient’s chief complaint, age, handdominance, and vocational and avocational activities. Although manypatients with glenohumeral joint instability have vague symptoms, commoncomplaints of patients with shoulder instability include pain, popping,catching, locking, an unstable sensation, stiffness, and swelling [32].When thepatient reports pain, the location, quality, intensity, and any radiation of thepain should be determined. The patient should be asked about exacerbatingand alleviating factors. It also is important to determine when the symptomsfirst were noticed, the frequency of symptoms, and positions or activities thatresult in instability episodes.

A history of acute trauma or chronic, repetitive microtrauma should beobtained. Some patients may have a history of glenohumeral jointdislocation, and the examiner should determine the direction of dislocation,


the duration of the dislocation, whether it has reoccurred, and whether itrequired manual reduction or reduced spontaneously. Subluxation episodescommonly are associated with a burning or aching dead feeling in the arm.Repetitive overhead activities, such as baseball pitching, may cause enoughmicrotrauma to lead to symptomatic laxity [32]. The patient should be askedwhether he or she or any family members have a history of generalizedligamentous laxity or connective tissue disorder.

The direction of instability may be elicited through historical information.Instability that occurs with the patient’s shoulder in the abducted andexternally rotated position suggests anterior instability [32]. Posteriorinstability is suggested by instability that occurs when the patient’s shoulderis forward flexed and internally rotated [32]. Pain, paresthesias, and weaknesswhile carrying heavy objects may indicate inferior instability [32]. Patientswith multidirectional instability may report symptoms of two or moreinstability patterns.

Physical examination

The physical examination should include inspection, palpation, gleno-humeral joint range of motion (ROM), upper extremity strength, sensation(including proprioception), reflex evaluations, and special tests for gleno-humeral joint instability. Adjacent joints should be evaluated to rule outreferred pain or concomitant pathology. A kinetic chain evaluation alsoshould be performed to ensure that deficits in distant regions are notcontributing to the glenohumeral joint instability.

The patient’s shoulder girdle should be inspected for posture, discolor-ation, swelling, scars, muscle atrophy, and deformity. Scapular positionshould be noted. Winging of the scapula may be associated withscapulothoracic dyskinesis, muscle imbalance or fatigue, or an injury tothe spinal accessory nerve or long thoracic nerve [1]. Scars that are thin orspreading may suggest an underlying connective tissue disorder [32].

Palpation should begin at the sternoclavicular joint and progressivelaterally to encompass the anterior, posterior, superior, inferior, andlateral aspects of the shoulder. Areas of deformity or tenderness should benoted.

ROM should be assessed actively and passively, including flexion,extension, abduction, adduction, and internal and external rotation. Internaland external rotation should be assessed with the arm at the side and with theshoulder abducted 90�. During the concentric and eccentric phases of activeshoulder abduction and forward flexion, scapulothoracic motion should beassessed for the presence of winging and abnormalities in the scapulothoracicrhythm, indicating scapulothoracic dyskinesis or weakness of the scapularstabilizers.

The lateral scapular slide measurement can be used as an objective testfor scapulothoracic movement symmetry. The distance from the inferior


angle of the scapula to the nearest spinous process is measured in threepositions: arms at the side, hands on the hips, and arms abducted 90�. Aside-to-side difference of 2 or more cm is considered significant [33].

Strength testing should include all of the upper extremity muscles, withan emphasis on the rotator cuff and scapular stabilizing muscles. Sensationshould be assessed in the C5 through T1 dermatomes and in the cutaneousnerve distributions of the upper extremities. Reflex testing should includethe biceps reflex (C5-6), brachioradialis or pronator reflex (C5-6), andtriceps reflex (C7-8) [34].

Clinical tests used to measure the proprioceptive and kinestheticabilities of the shoulder commonly consist of angular reproduction andthreshold to sensation of movement maneuvers. Functional testingprocedures, such as the closed kinetic chain upper extremity stabilitytest [35] and functional throwing performance index [36], also can providereliable information.

Special tests for instability

Anterior apprehension (crank) and relocation testsThe anterior apprehension (crank) and relocation tests (Fig. 1) are for

anterior glenohumeral joint instability. The patient is placed in the supineposition. The examiner abducts the patient’s shoulder 90� and flexes theelbow 90�. The examiner uses one hand slowly to externally rotate thepatient’s humerus using the patient’s forearm as the lever, while the otherhand is placed posterior to the patient’s proximal humerus and exerts ananteriorly directed force on the humeral head. The test is considered positiveif the patient indicates a feeling of impending anterior dislocation [37]. Therelocation test is positive if the examiner removes the hand from behind theproximal humerus, places it over the anterior proximal humerus, and exertsa posteriorly directed force, and the patient reports a reduction in theapprehension [37].

Anterior and posterior drawer testsThe anterior drawer test (Fig. 2A) is used to evaluate anterior

glenohumeral joint instability, whereas the posterior drawer test (Fig. 2B)is used to evaluate posterior glenohumeral joint instability. The patient isplaced supine on the examination table. The hand of the patient’s affectedshoulder is placed in the examiner’s axilla and grasped by the examiner’s arm.The patient’s shoulder is abducted 80� to 120� and flexed 0 to 20�. Theexaminer uses the other hand to stabilize the scapula andmonitor for anteriortranslation of the shoulder. The examiner grasps the patient’s proximalhumerus with the remaining hand and exerts an anteriorly directed force onthe humeral head. A positive test is indicated by excessive anterior translationof the humerus relative to the glenoid. This test may be accompanied byapprehension or a click [38].


The posterior drawer test begins with the patient in a supine position.The examiner grasps the patient’s proximal forearm with one hand, flexingthe patient’s elbow to 120�, abducting the shoulder to 80� to 120�, andflexing the shoulder 20� to 30�. The examiner’s other hand stabilizes thescapula with the thumb over the anterior aspect of the shoulder just lateralto the coracoid process and the remaining fingers along the posteriorshoulder. The test occurs when the examiner forward flexes the shoulder60� to 80� while placing a posteriorly directed force against the patient’shumeral head with the thumb of the other hand. The same hand that isexerting the posteriorly directed force on the humeral head also monitorsthe humeral head for posterior translation, which indicates a positive test[38].

Fig. 1. (A) Anterior apprehension test. (B) Relocation test.


Load and shift testFor the load and shift test (Fig. 3), the patient is in a seated positionwith the

arms at the sides. The examiner stabilizes the patient’s affected shoulder withone hand,while pressing the humeral head into the glenoid fossawith the otherhand. An anterior and posterior force is placed on the proximal humerus, andthe amount of humeral anterior and posterior translation is assessed [39].

Posterior apprehension testThe posterior apprehension test (Fig. 4) evaluates posterior glenohumeral

joint stability. The patient’s affected shoulder is forward flexed to 90�, then

Fig. 2. (A) Anterior drawer test. (B) Posterior drawer test.


maximally internally rotated. A posteriorly directed force is placed on thepatient’s elbow by the examiner. A positive test causes a 50% or greaterposterior translation of the humeral head or a feeling of apprehension in thepatient [40].

Jerk testThe jerk test is another test to evaluate posterior glenohumeral joint

stability. The patient is seated, and the shoulder is abducted 90� andmaximally internally rotated. The patient’s elbow is grasped by the examiner,and an axial load is placed through the humerus. The patient’s arm isadducted horizontally across the body while maintaining the axial load. A

Fig. 3. (A) Anterior load and shift test. (B) Posterior load and shift test.


positive test is indicated by a posterior ‘‘jerk’’ of the humeral head as itdisplaces posteriorly. It may relocate with another jerk as the arm is returnedback to an abducted position [40].

Sulcus signThe sulcus sign (Fig. 5) is used to evaluate inferior glenohumeral joint

instability. The patient is seated or standing with the arm relaxed at the side.The patient’s forearm is grasped by the examiner, and a distal traction force

Fig. 4. Posterior apprehension test.

Fig. 5. Sulcus sign.


is placed through the patient’s arm. In the presence of inferior instability,a sulcus develops between the humeral head and the acromion [40].

Feagin testThe Feagin test (Fig. 6) also is used to assess inferior glenohumeral joint

stability. The patient is seated or standing with the arm abducted 90�, theelbow extended, and the forearm resting on the examiner’s shoulder. Theexaminer clasps the hands together over the patient’s proximal humerus andexerts a downward force. The test is considered positive if the patient feelsapprehension [40].

Radiologic evaluation

The various lesions commonly seen with glenohumeral joint instabilitywere discussed earlier. The most common initial radiographic views for theevaluation of glenohumeral joint instability include the anteroposteriorshoulder view, axillary lateral view, and scapular ‘‘Y’’ view [6]. Theanteroposterior view allows visualization of the osseous structures of theshoulder, including the scapula, clavicle, upper ribs, humeral head, andglenoid rim [30]. With internal rotation, the anteroposterior view also mayallow visualization of aHill-Sachs defect [30]. The scapular Y view can help toassess glenohumeral joint alignment after acute dislocations [30]. The axillarylateral view can assess anterior or posterior subluxation or dislocation andfractures of the anterior or posterior glenoid rim [30]. Other specialized viewsinclude the Garth view and the West Point view, both of which are useful inthe detection of Bankart fractures; the Stryker Notch view for the evaluation

Fig. 6. Feagin test.


of Hill-Sachs defects; and stress views for the documentation of the degree ofglenohumeral joint instability [30].

CT was previously the gold standard for glenoid labral evaluation. Withthe advent of MRI and magnetic resonance arthrography, however, CT nowhas a limited role. MRI and magnetic resonance arthrography providesuperior visualization of the labrum, cartilage, and joint capsule without theionizing radiation of CT. Visualization of nondisplaced injuries to the inferiorglenohumeral ligament or anterior-inferior glenoid labrum is improved byplacing the arm in an abducted and externally rotated position.

Treatment

The treatment options for glenohumeral joint instability and dislocationinclude nonoperative and operative approaches. After glenohumeral jointsubluxation episodes and in patients with multidirectional instability,a comprehensive rehabilitation program that addresses kinetic chain deficits;scapulothoracic mechanics; and shoulder girdle strength, flexibility, andneuromuscular control is appropriate. Such a program is discussed in thenonoperative treatment section. For patients who have a first-time anteriorglenohumeral joint dislocation, the decision between trials of nonoperativetreatment versus immediate surgical stabilization is more controversial.Although the rehabilitation of acute anterior glenohumeral joint dislocationis addressed in the nonoperative treatment section, the controversy betweensurgical and nonsurgical treatment is addressed in the surgical section.

Regardless of whether a patient chooses early surgical intervention, closedreduction confirmed by radiologic examination should be performed on allpatients who sustain an acute glenohumeral joint dislocation that does notreduce spontaneously. Radiologic studies should be performed in two planes(eg, anteroposterior with the humerus in internal rotation and axillary lateralviews) to confirm relocation and exclude an associated fracture [30]. Sensorytesting over the deltoid muscle is important because the axillary nerve is themost commonly injured nerve after shoulder dislocation [6]. Immobilizationof the glenohumeral joint after relocation does not seem to affect the rate ofglenohumeral joint redislocation and should be considered only a comfortmeasure [41–43]. Medications such as nonsteroidal anti-inflammatory drugsandmild narcotics may be considered for initial pain control. Specific surgicaland rehabilitative treatments are discussed in subsequent sections.

Nonoperative treatment

After a thorough examination, an individualized rehabilitation programbased on the specific deficits identified is developed. The nonoperativetreatment of glenohumeral joint instability should include pain and edemacontrol, monitoring and restoring shoulder girdle ROM, protection of thestatic glenohumeral joint stabilizers, obtaining full function of the dynamic


stabilizers, restoring joint proprioception, and correcting associated kineticchain deficits. The ultimate goal of this program should be the unrestrictedreturn of the patient to preinjury activities.

Initially, treatment of the unstable shoulder emphasizes controlling painand edema, protecting healing tissues, and decreasing the deleterious effectsof immobilization. After acute dislocation, positions of tissue stress should beavoided, such as shoulder abduction and external rotation in patients whohave sustained an anterior dislocation. Modalities such as interferentialelectrical stimulation, ultrasound, soft tissue mobilization, and cryotherapymay be beneficial for reduction of pain and edema and promotion of tissuehealing.

Taping the unstable shoulder can help to decrease pain, improve jointbiomechanics, and enhance neuromuscular reeducation of the shouldercomplex musculature. Taping can reduce anterior humeral head translationin patients with anterior instability and can be used to elevate and center thehumeral head in the glenoid fossa for patients with multidirectionalinstability (Fig. 7). This positioning maintains proper shoulder girdlealignment during neuromuscular reeducation training [44].

The principles of glenohumeral joint tissue protection include avoidingimpingement positions, decreasing capsular stress, and preventing tendonoverload. Strategies include keeping the humerus at less than 90� of elevationand at or anterior to the plane of the scapula and using a low-resistance, high-repetition exercise format [45]. Exercising in the plane of the scapula often isrecommended because it optimizes rotator cuff length-tension relationships,reduces stress on capsuloligamentous structures, and provides maximalglenohumeral joint surface conformity [46,47]. Exercising in the plane of thescapula also is functional because most shoulder activities occur in this plane.

Occasionally, patients with anterior instability display posterior gleno-humeral joint capsular tightness. This tightness can cause an increase inanterior glenohumeral joint capsular stress. Posterior glenohumeral jointcapsular tightness frequently is found in throwing athletes [48]. Mobilizingthe glenohumeral joint using a posterior glide technique and horizontallyadducting the internally rotated arm are useful techniques for stretching theposterior capsule (Fig. 8).

Reestablishing appropriate force couples about the glenohumeral andscapulothoracic joints is important during rehabilitation. One significantforce couple involves the synergistic contraction of the deltoid, supra-spinatus, infraspinatus, teres minor, and subscapularis to allow glenohumeraljoint abduction. Another force couple involves the coordinated contractionof the serratus anterior and upper and lower trapezius to facilitate upwardrotation of the scapula during shoulder elevation. Patients with glenohumeraljoint instabilities frequently have abnormalities in these force couples,particularly in the scapular stabilizers [49,50].

When strengthening the rotator cuff for the treatment of specificinstability patterns, it is important to remember Dempster’s ring concept


of glenohumeral joint instability, as mentioned earlier [7]. It has been foundthat any stress on the stabilizers of one side of the glenohumeral joint alsoplaces stress on the stabilizers of the opposite side of the joint. This findingsuggests that the reciprocal also is true—that strengthening the stabilizers oneither side of the glenohumeral joint helps prevent unidirectional instability.

Fig. 7. (A) Anterior instability taping. Tape is used to lift the head of the humerus superiorly

and posteriorly so that the head of the humerus is slightly externally rotated. The tape is pulled

diagonally across the scapula, ending just medial to the inferior border of the scapula. (B)

Multidirectional instability taping. Tape is used to elevate the humeral head and center it in the

glenoid. The patient rests the arm in 45� of abduction. The humeral head is placed manually in

neutral position. The first piece of tape is anchored over the middle deltoid and pulled

superiorly to attach over the acromion. The second piece begins anteriorly on the humerus,

passes diagonally over the clavicle, and is anchored on the spine of the scapula. The third piece

of tape is placed along the posterior deltoid and is anchored along the upper trapezius.


Using this rationale, it is important to strengthen the anterior and posteriorcuff and scapular muscles for the treatment of anterior and posteriorunidirectional glenohumeral joint instability [51,52]. For inferior gleno-humeral joint instability, strengthening the deltoid and supraspinatus helpsprevent inferior migration of the humerus. Multidirectional instabilityrequires strengthening of all of the rotator cuff muscles, the long head of thebiceps, and the deltoid.

Because the rotator cuff muscles provide dynamic stability for theglenohumeral joint, and the length-tension relationship of the rotator cuffdepends on scapular position, the rehabilitation program needs to address thestrength, endurance, and neuromuscular control of the rotator cuff and

Fig. 7 (continued )


scapular stabilizing muscles. Initial strengthening exercises should includemultiple angle, submaximal isometric muscular contractions to beginneuromuscular reeducation, develop strength, and improve local blood flow[53]. This program progresses to isotonic exercises within a limited ROMusing manual resistance, light weights, or resistance cords. Initial scapularneuromuscular control training may begin with manually assisted or resistedprotraction and retraction in sitting or side-lying position using a low-resistance, high-repetition format. Rehabilitation exercises eventually shouldprogress to multiplanar activities in the full range of shoulder motion,incorporating isotonic, isokinetic, and isodynamic resistance at submaximaland maximal levels. Strength training should be activity specific so thatexercises are performed in a functional position and proper muscle synergiesare used [54]. A swimmer should be trained in a prone or supine position(depending on his or her stroke), whereas a tennis player should train in anupright position, and the exercise movements should simulate those ofa swimming or tennis stroke. Plyometric exercises are the last to be addedbecause they generate the most force through the shoulder girdle. Theseexercises are an important component of the rehabilitation program,however, because many activities, particularly sports, require explosivemovements that can be mimicked only through plyometric exercises.

Rotator cuff strengthening can be done with resisted internal and externalrotation of the shoulder with the arm in the scapular plane [55]. Exercises thatcommonly are used to produce increased levels of posterior rotator cuffelectromyographic activation include resisted prone external rotation withthe shoulder abducted 90�, resisted side-lying external shoulder rotation, andresisted prone shoulder extension, abduction with external rotation, androwing [55–57]. Strengthening of the supraspinatus involves humeralelevation in the plane of the scapula. This exercise can be performed withthe humerus in an externally rather than internally rotated position because

Fig. 8. Posterior glide in the loose pack position.


this reduces subacromial impingement and does not appear to alterelectromyographic activity in the supraspinatus muscle [55]. Elastic tubingor pulleys can be used to strengthen the infraspinatus, teres minor, andposterior deltoid muscles eccentrically, which is important because thesemuscles frequently are called on to decelerate the shoulder. Bicepsstrengthening is important and may include exercises such as resisted elbowflexion at multiple angles of shoulder flexion and scapular plane elevation.Strengthening exercises for the scapular stabilizers need to address thesuperior, middle, and inferior aspects of the trapezius muscle and therhomboideus major and minor, levator scapula, serratus anterior, andpectoralis minormuscles. Commonly used exercises include rowing, push-upswith a plus, shoulder shrugs, and seated press-ups (Fig. 9) [58].

Fig. 9. (A) Push-up with a plus. The scapula is protracted at the end of a push-up to increase

serratus anterior activation. (B) Prone rowing.


Exercises with combined movement patterns also are used to reestablishfunction. Combined movement patterns, such as the proprioceptiveneuromuscular facilitation D2 flexion pattern for the upper extremities,which consists of abduction, flexion, and external rotation, can be usedduring functional neuromuscular reeducation (Fig. 10) [49]. The use of theclosed kinetic chain exercise also is important for strengthening the unstableshoulder. The benefits of closed chain exercise include muscular cocon-traction, cohesion of joint surfaces, and multijoint training [59]. Examples ofclosed kinetic chain exercise include hand step-ups; rhythmic stabilizationactivities in biped, triped, and quadruped positions; push-ups with additionalscapular protraction; and seated press-ups (Fig. 11).

Throughout the rehabilitation program, postural and kinetic chain deficitsneed to be identified and corrected. Kinetic chain deficits frequently present inpatients with shoulder instability and include dynamic pes planus, inflexiblequadriceps, hip flexors, iliotibial band, latissimus dorsi, and pectoralis majorand minor muscles; weak hip girdle musculature; and restricted hip internalrotation and thoracic rotation. Patients with glenohumeral joint instabilityalso frequently have postural abnormalities, such as a head-forward positionand protracted scapula with rounded shoulders.

As discussed earlier, patients with shoulder instability frequentlyexperience proprioceptive deficits [60–62]. Rehabilitative exercises to enhanceproprioception include rhythmic stabilization and ball tossing activities invarying degrees of abduction and external rotation and proprioceptiveneuromuscular facilitation drills using exercise tubing and manual resistanceconcomitantly (Fig. 12) [49].

Surgical treatment

Surgical treatment options for shoulder instability are based on theinformation gathered during the history, physical examination, diagnosticimaging, and examination under anesthesia. The age of the patient, activitylevel, extremity dominance, degree of instability, traumatic versus atraumaticorigin, and its direction all are important determinants of appropriatetreatment. Finally, the pathology indicated by imaging studies or findings atthe time of surgery dictates the appropriate surgical interventions. In additionto the standard risks of surgery, complications unique to shoulderstabilization surgery include recurrent instability; migration of suture anchorsor suture tacks, which may cause articular damage; and injury to the axillaryor suprascapular nerves [63]. These complications need to be explained to thepatient in detail before any surgical intervention so that the patient can makean informed decision regarding treatment.

One classification system that frequently is used to divide patients intononoperative and surgical categories is the TUBS and AMBRI mnemonics.TUBS stands for traumatic instability that is unidirectional and has anassociatedBankart lesion, which responds best to surgical treatment.AMBRI


stands for atraumatic instability that is multidirectional and bilateral. Thetreatment begins with rehabilitation, and if this fails, surgical treatmentinvolves an inferior capsular shift. This classification is oversimplified, doesnot address patients with unidirectional instability patterns that are not justanterior, and does not address patients who sustain recurrent dislocations.These areas are addressed in subsequent sections.

Examination under anesthesia

A meticulous examination under anesthesia must be performed beforeshoulder surgery. Passive shoulder ranges of motion, including elevation,

Fig. 10. Proprioceptive neuromuscular facilitation D2 flexion pattern. This is a diagonal

pattern consisting of shoulder abduction, external rotation, and flexion.


external rotation, and internal rotation with the arm at the side and at 90� ofabduction, are recorded. The examination should be performed with thepatient supine or in the beach-chair position with both arms available forcomparison. Anterior and posterior stability is assessed with the arm ab-ducted 90� and in neutral rotation with anterior and posterior forces applied.Application of axial pressure during this maneuver is crucial. Translation isgraded as follows: 1—no translation, 2—mild translation, 3—moderatetranslation with progression to the rim of the glenoid, 4—dislocation of theglenohumeral joint. Physiologic translation is usually a grade 2. The arm istested in 90� of external rotation and 45� of internal rotation to assess theanterior-inferior and anterior-posterior capsules. Studies comparing the

Fig. 11. Examples of closed chain shoulder exercises to facilitate cocontraction and enhance

neuromuscular control. (A) Hand step-ups. Stepping on and off of a step with the scapula in

a protracted position. (B) Rhythmic stabilization. Perturbation of a patient in the biped

position.


examination under anesthesia with eventual findings observed at surgeryshow sensitivity of 100% and specificity of 93% [63].

Surgical treatment of anterior instability

After a traumatic anterior glenohumeral joint dislocation, treatmentoptions include nonoperative and surgical interventions. In older, less activepatients, nonoperative management frequently is successful [64]. In younger,more active patients involved in contact sports, studies have shown a highredislocation rate in patients treated nonoperatively compared with patientsreceiving early operative intervention [63,65–67]. Open and arthroscopictechniques can be used, and modalities such as laser, thermal probes, ortraditional suturing may be indicated based on the pathoanatomy.Indications for surgery in first-time traumatic anterior glenohumeral jointdislocation patients include patients who have failed conservative manage-ment and young patients who are involved in contact sports or other high-demand occupations [65,68,69].

Historically, surgical intervention was limited to scarification of theanterior capsule for dislocations. Early procedures created soft tissuecontracture and bony block to prevent further dislocation. The increasedpathoanatomic understanding of shoulder instability has allowed significantimprovements in surgical techniques and their subsequent outcomes [68,70].

Open stabilization of anterior glenohumeral instability has been usedfrequently in the athletic population, with one study reporting that 96% ofprofessional athletes treated with this technique were able to return to theirsport [68]. Open stabilization is done best with the patient in the beach-chair

Fig. 12. Rhythmic stabilization exercise in which the patient tries to hold the shoulder in a static

position against stretch cord resistance, while the clinician places perturbations against the

patient’s arm.


position. An anterior axillary approach allows separation of the deltopec-toral interval, preservation of the cephalic vein, and adequate visualizationof the damaged tissue. The subscapularis tendon is incised 1 cm medial to itsinsertion, and the capsule is separated from its undersurface. The Bankartlesion is repaired using direct suture to the glenoid or with suture anchors,and the capsular redundancy is eliminated with a superior shift. Thesubscapularis tendon is repaired and the skin approximated. Postoperativerehabilitation needs to allow the repaired tissue adequate time to heal.

Arthroscopic stabilization procedures seem to have many benefits overopen procedures, including decreased operating room time, blood loss,narcotic use, hospital stay, time lost from work, and complications comparedwith open procedures [68,71–76]. The first arthroscopic shoulder stabilizationprocedure using a capsular staple was done in 1982 [63]. Arthroscopictechniques, including transglenoid suture repair, suture anchors, suture tacks,thermal capsulorrhaphy, and laser, all have been compared with opentechniques. Although early studies revealed relatively high redislocation ratesafter arthroscopic repair, more recent literature indicates that the redis-location rate after arthroscopy is now only 15%, and the redislocation rateafter open repair is approximately 10% [71–76]. Bioabsorbable sutureanchors have become popular; the most common bioabsorbable materialused today in the shoulder is poly-L-lactic acid. Contraindications toarthroscopic techniques include patients with glenoid bone loss, attenuatedcapsulolabral tissue, engaging Hill-Sachs lesions, and humeral avulsion of theglenohumeral ligament lesions.

Thermal or laser shrinkage of the capsule addresses capsular stretchingthat may occur with instability events [77]. This technique has the advantageof not altering the inherent anatomy, and it is not technically demanding.These tissues are at risk for recurrent stretching, however, and long-termsuccess with this treatment is questionable [77–83]. Arthroscopic capsularplication or capsular tucks have been performed to avoid using the thermalenergy on capsular tissue. Capsular plication involves roughening the capsuleusing a shaver, followed by the passage of a suture through the capsule andthe labrum. Capsular tucks are made inferiorly and progressing superiorly tothe rotator interval. The sutures are tied resulting in a tightening of the jointcapsule and glenohumeral ligaments. The size of the tucks determines thedegree of capsular and ligamentous shortening. The most difficult portion ofthis technique is tensioning the capsule appropriately [84].

Surgical treatment of multidirectional instability

Multidirectional instability is a difficult problem and should be treatedsurgically only if conservative measures fail. Neer and Foster [83] firstdescribed the open capsular shift for multidirectional instability in 1980, andit continues to be the gold standard today with reported success rates of 92%to 94% [85–90]. More recent advances in the treatment of multidirectional


instability have been accomplished using the arthroscope with success rates of70% to 90% [91–96]. Capsular tension can be addressed with plicationsutures in the anterior and the posterior capsule, followed by thermalcapsulorrhaphy for any further redundancy. Thermal capsulorrhaphy now isused primarily for augmentation of capsular plication rather than asa primary form of treatment for global instability [93–96]. Two anteriorportals are required to allow access to appropriate areas of the capsule. Forposterior plication, two posterior portals also are required to place suturesand use the electrothermal device to tension this tissue appropriately. Rotatorinterval closure has been advocated to assist in capsular tensioning.Additional pathology, such as superior labral anterior posterior lesions andposterior impingement lesions resulting from this instability, also need to beaddressed at the time of surgery.

Surgical treatment of posterior instability

Treatment of posterior instability is initially nonoperative. If thistreatment fails, however, open or arthroscopic posterior Bankart repair withappropriate capsular plication is effective in 80% to 90% of these patients[10,97–100].

Postoperative rehabilitation

Although the specific postsurgical rehabilitation protocol varies accordingto the surgeon and type of surgery performed, the goal of rehabilitation is thesame—to obtain full static and dynamic function of the shoulder. Many ofthe exercises used postoperatively are similar to the exercises used for thestandard nonoperative treatment of shoulder instabilities. PostoperativeROM considerations are crucial in these patients, however.

Frequently a short period of shoulder immobilization is required aftershoulder stabilization surgery. Early protected ROM activities are importantto institute as soon as possible, however, to prevent the adverse effects ofimmobilization, such as collagen malalignment and articular cartilagedegeneration, to name a few.Evaluation of tissue readiness, type of instability,type of surgical procedure, tissue status, and method of fixation should beconsidered before performing ROM and strengthening activities [49].

Specific postoperative rehabilitation protocols

Bankart procedureFrequently after open anterior stabilization surgery, external rotation is

limited to 40� in the plane of the scapula for the first 4 weeks and is progressedto 90� of external rotation in the abducted position 6 weeks postoperatively.Full ROM is allowed by 8 weeks postoperatively. If the subscapularis muscleis detached then reattached during open reconstruction, resistive internalrotation should be limited initially.


After arthroscopic surgery, the rate of progression is more conservative.External rotation usually is limited to 25� in the plane of the scapula for thefirst 6 weeks and progressed to full ROM at 10 weeks. A commoncomplication after anterior shoulder stabilization surgery is loss of motion,particularly external rotation. Should this loss of motion occur, jointmobilization and stretching may be performed to stretch the anteriorshoulder capsule to increase shoulder external rotation (Fig. 13).

Capsular-shift procedures (anterior or inferior)Postoperative rehabilitation for multidirectional instability is treated with

a more conservative program than used for anterior instability. Patientswith congenital instability are progressed more slowly than patients withacquired instability. The goal is to restore shoulder motion to approximately10� to 15� less than the preoperative level by 10 to 12 weeks postoperatively[50]. The ROM exercises are progressed based on end feel. If the patientexhibits a soft end feel and motion is greater than guidelines, motion isslowed; conversely, if the patient exhibits a hard or firm end feel and lessmotion than the guideline, motion is accelerated [50].

Posterior instability proceduresThere is usually a period of immobilization after posterior stabilization

due to the thin posterior capsule. The combinedmovement of flexion, internalrotation, and horizontal adduction is avoided for 6 weeks postoperatively.

Thermal capsulorrhaphyRehabilitation for thermal capsulorrhaphy involves a period of immobi-

lization before beginning ROM activities. The ROM is usually restoredwithin 8 weeks.

Fig. 13. Anterior glide mobilization of the shoulder for anterior capsular tightness.


Summary

Glenohumeral joint instability involves multiple different diagnoses witha broad range of underlying pathology. It is important to understand theanatomy, pathology, history, physical examination, and classificationsystems to diagnose these patients correctly. After arriving at an accuratediagnosis, an appropriate treatment program that may entail nonoperativeor surgical interventions can be instituted.

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