Definition Of Shoulder Dislocation

Definition of Shoulder dislocation Shoulder dislocation: Displacement of the ball of the shoulder joint (the top rounded portion of the upper arm bone, or humerus) from the socket of the joint (the glenoid fossa of the wingbone, or scapula). There is complete separation of the humerus from the scapular glenoid. The shoulder joint is the most frequently dislocated major joint of the body, reflecting the fact that it sacrifices stability for mobility. Most of these dislocations are due to trauma .Treatment involves reduction of the dislocation, immobilization of the arm in a sling for 1 to 3 weeks, and physical therapy. Also known as glenohumeral dislocation. Sex Gender distribution is bimodal, with peak incidence in men aged 20-30 years (with a male-to-female ratio of 9:1) and in women aged 61-80 years (with a female-tomale ratio of 3:1). Age Shoulder dislocation occurs more frequently in adolescents than in younger children because the weaker epiphyseal growth plates in children tend to fracture before dislocation. In older adults, collagen fibers have fewer cross-links, making the joint capsule and supporting tendons and ligaments weaker and dislocation more likely.

1

Anterior dislocation is most commonly seen in those aged 18-25 years due to sporting injury. The second most common age group to sustain anterior dislocation is in elderly persons due to their susceptibility to falls.

Pathological changes; In following pathological changes occur in the commoner ,anterior dislocation bankarts lesion ;dislocation causes stripping of the glenoidal labrum along with the periostieum from the anterior surface of the glenoid and scapular neck.the head thus comes to lie in front of the scapular neck ,in the pouch thereby created. b) Hill-sachs lesion; this is a depression on the humeralhead in its postero-lateral quadrant,caused by the anterior edge of the glenoid on the head as it dislocates. c)Roundening off of the anterior glenoid rim occurs as the head dislocate over it. d) The may be associated fractures of greater tuberosity of greater tuberosity of the humerus or of rim of the glenoid.

2

3

4

ANATOMY

ANATOMY OF SHOULDER COMPLEX The shoulder complex, composed of the clavicle, scapula and humerus, is an intricately designed combination of three joints linking the upper extremity to the thorax. The articular structures of the shoulder complex are designed primarily for mobility, allowing us to move and position the hand through a wide range of space. The shoulder complex is connected to the axial skelton by a single anatomic joint that is Sternoclavicular (SC) joint.

COMPONENTS OF THE SHOULDER COMPLEX

5

The osseous segment of the shoulder complex are the clavicle, scapula and humerus (Figure 3). These three segments are joined by three interdependent linkages:- The Sternoclavicular(SC) joint, Acromioclavicular(AC) joint and the Glenohumeral(GH) joint. The articulation between the scapula and the thorax is Scapulothoracic(ST) “joint”. It does not have characteristics of a fibrous, cartilageous or synovial union rather it is “Functional Joint”. Instead, the scapular motion on the thorox is directly a function of Sternoclavicular, Acromioclavicular or combined Sternoclavicular and Acromioclavicular joint motion. An additional functional articulation is subacromial (or suprahumeral) “joint”. This functional joint is formed by movement of the head of the humerus below the coracoacromial arch.

Figure 3.Anatomy of the shoulder joint

Sternoclavicular Joint The SC joint serves as the only structural attachment of the clavicle, scapula and upper extremity to the axial skelton.

6

Due to concave convex shape of the articular surfaces the joint can be classified as a Plane Synovial Saddle joint. This joint has a synovial capsule, a joint disk and three major ligaments.

Articulating structures The SC articulation consist of two saddle – shaped surfaces, one at the sternal or medial end of the clavicle and one at the notch formed by the manubrium of the sternum and first costal cartilage. The sternal end of the clavicle and the manubrium are incongruent; that is there is little contact between their articular surfaces.

The superior portion of the medial clavicle does not

contact the manubrium at all, serves as the attachment of sternoclavicular joint disk and interclavicular ligament.

Sternoclavicular Disk The SC joint has a fibrocartilage joint disk that increases congruence between joint surfaces.  The upper portion of the SC disk has attachment to the postero superior

clavicle.  The lower portion is attached to the manubrium and first costal cartilage, as well as the anterior and posterior aspects to the fibrous capsule. The disk diagonally transects the SC joint space and divide the joint into two separate cavities. The disk acts like a hinge or pivot point during clavicle motion.

Sternoclavicular Joint Capsule and Ligaments

7

The SC joint is surrounded by a fairly strong fibrous capsule and three ligaments for the majority of its support. These ligaments are:1.

Sternoclavicular ligament:-

SC ligament is attached laterally to

the sternum and on first costal cartilage. It is strong inferiorly and posteriorly where it constitute the anterior posterior ligaments. 2.

Costoclavicular ligament :-

Costoclavicular ligament is attached

above to the rough area of the inferior aspect of the medial end of the clavicle. Inferiorly it is attached to the first costal cartilage and to the first rib. 3.

Interclavicular ligament:-Interclavicular ligament passes between the sternal end of the right and left clavicle and upper border of the manubrium sterni.

Blood Supply:- Internal thoracic and supra – scapular artery. Nerve Supply:- Medial supraclavicular nerve.

Acromioclavicular Joint:The AC joint attaches the scapula to the clavicle. It is a plane synovial joint. It has a joint capsule and two major ligaments, a joint disk may or may not be present.

Articulating Surfaces:-

8

The AC joint consist of the articulation between the lateral end of the clavicle and a small facet on the acromion of the scapula. The articular facet considered to be incongruent, vary in configuration. They may be flat, reciprocally concave – convex or reversed. The facets are covered with fibrocartilage.

Acromio Clavicular Joint disk:The cavity of the joint is occasionally subdivided by an articular disk. The disk of the joint vary in size and differs among individual.

Acromio Clavicular Capsule and Ligament:The capsule of the joint is weak and cannot maintain integrity of the joint without reinforcement of the ligaments. These ligaments as – 1.

Superior and Inferior Acromio Clavicular Ligament The fibres of the superior AC ligament are reinforced by aponeurotic fibres of the trapezius and deltoid muscles making the superior joint stronger then inferior.

2.

Coraco Clavicular Ligaments:-

This ligament is divided into a

lateral portion, the trapezoid ligament, and a medial portion, the conoid ligament. The trapezoid part is attached below to the upper surface of the coracoid process and above to trapezoid on the inferior surface of lateral part of clavicle.

It is quadrilateral in shape and is nearly

horizontal.

9

The conoid part is attached below to the coracoid process just lateral to the scapular notch. It is attached above to inferior surface of the clavicle on the conoid tubercle. The conoid ligament is triangular and vertically oriented (medially and slightly posterior to the trapezoid). The two parts of ligaments are separated

by adipose tissue and

large bursa

Blood Supply:- Supra scapular and thoracoacromial artery. Nerve Supply:- Lateral supra clavicular nerve. Glenohumeral Joint:The GH joint is a synovial joint of ball and socket variety. It has a capsule and several associated ligaments and bursa.

ArticulationThe articulation is formed by the – Glenoid fossa of scapula proximally. Head of the humerus distally. Structurally it is a weak joint because of the glenoid cavity which is too small and shallow to hold the head of humerus in place. However this arrangement permits great mobility the stability is maintained by the following factors – 1.

Coracoacroial arch or secondary socket for the head of humerus.

10

2.

Musculotendinous cuff of shoulder joint.( Figure 4)

Figure 4.Musculotendinous cuff 3.

Glenoid labrum.

Glenoid Labrum The total available articular surface of the glenoid fossa in enhanced by an accessory structure, the glenoid labrum. This structure surrounds and is attached to the periphery of the glenoid fossa, enhancing the depth or curvature of the fossa by approximately 50%. The labrum superiorly is loosely attached whereas the inferior portion is firmly attached and relatively immobile. The glenoid labrum also serves as the attachment site for the glenohumeral ligaments and the tendon of long head of bicep brachii.

Glenohumeral Capsule and Ligament The entire GH joint is surrounded by a large, loose capsule that is taut superiorly and slack anteriorly and inferiorly in the resting position (arm

11

dependent at the side). The capsular surface area is twice that of humeral head. The relative laxity of the GH capsule is necessary for the large excursion of joint surfaces but provides little stability without the reinforcement of ligaments and muscles. When the humerus is abducted and laterally rotated on the glenoid fossa, the capsule twist on itself and tightens, making abduction and lateral rotation the close – packed position for the GH joint. The capsule is reinforced by following ligaments:1.

Superior GH ligaments.

2.

Middle GH ligaments.

3.

Inferior GH ligaments.

4.

Coracohumeral ligaments.

The three GH ligaments vary considerably in size and extent and may change with age. The superior GH ligaments passes from the superior glenoid labrum to the upper neck of humerus deep to coracohumeral ligament.

The superior GH ligaments, the superior capsule, and the

coracohumeral ligament are interconnected structures that bridge the space between the supraspinatus and subscapularis muscle tendon, forming Rotator Interval Capsule. The middle GH ligament runs obliquely from the superior anterior labrum to the anterior aspect of proximal humerus below the superior GH ligaments attachment. The inferior GH having at least three portions and thus have been termed the inferior GH ligaments complex (IGHLC). The three components of the

12

complex are the anterior and posterior bands and the axillary’s pouch in between. The corocohumeral ligament originates from the base of the coracoid process and may be defined as having two bands. The first insert into the edge of the supraspinatus and onto the greater tubercle, where it joins the superior GH ligaments; the other band insert into the subscapularis and lesser tubercle. The two band forms a tunnel through which the tendon of the long head of bicep brachii passes. As part of the rotator interval capsule, it appear to be the most important in limiting inferior translation of humeral head in the dependent arm.

Coracoacromial Arch The Coracoacromial (or suprahumeral) arch is formed by the coracoid process, the acromion, and the Coracoacromial ligament that spans the two bony projections. Often the inferior surface of the AC joint is included as well( Figure 5).

13

Figure 5.Coracoacromial arch The Coracoacromial arch forms an osteoligamentous vault that covers the humeral head and forms a space within which the Subacromial bursa, the rotator cuff tendons, and a portion of the tendon of long head of bicep brachii lie. The Coracoacromial arch protects the structures beneath it from direct trauma from above. The arch also prevents the head of humerus from dislocating superiorly, because an unopposed upward translatory force on humerus would cause the head of humerus to hit the Coracoacromial arch, however the contact of humeral head with the undersurface of the arch can simultaneously cause painful impingement.

Glenohumeral Bursae There are various bursae present indicative of the potential for functional forces between structures. They are – 1.

Subacromial bursa (Figure 6)

2.

Subdeltoid bursa

3.

Subscapularis bursa

4.

Infraspinatus bursa

5.

Several other bursa related to the coracobrachialis, teres major, long head of the triceps, latissimus dorsi and the coracoid process are present.

14

Figure 6. Subacromial bursa

Relations 

Superiorly -

Coracoacromial

arch,

subacromial

bursa,

supraspinatus and deltoid muscle. 

Inferiorly -

Long head of triceps



Anteriorly -

Short head of biceps and deltoid, subscapularis,

coracobrachialis. 

Posteriorly -

Infraspinatus, teres minor and deltoid muscle.



Within the joint – Tendon of long head of bicep brachii.

Blood Supply 1.

Anterior circumflex humeral artery.

2.

Posterior circumflex humeral artery. 15

3.

Suprascapular artery.

4.

Subscapular artery.

Nerve Supply 1.

Axillary nerve

2.

Musculocutaneous nerve

3.

Suprascapular nerve

Scapulothoracic Joint It is not a true anatomical joint because it has none of the usual joint characterstics (union by fibrous, cartilageous, or synovial tissues).

Articulating Surfaces The scapulothoracic “joint” is formed by the articulation of the scapula with the thorax. The articulation of the scapula with the thorax depends on the integrity of the anatomic AC and SC joints. The SC and AC joints are interdependent with the ST joint because the scapula is attached by its acromion process to the lateral end of clavicle through the AC joint; the clavicle, in turn, is attached to the axial skelton at the manubrium of the sternum through SC joint. Any movement of the scapula on the thorax must result in movement at either the AC and SC joint, or both; that is functional ST joint is part of a true closed chain with AC and SC joint and the thorax. Normally, the scapula rests at a position on the posterior thorax approximately 2 inches from the midline, between the second through

16

seventh ribs. The scapula is internally rotated 30o to 45o from the coronal plane, is tipped anteriorly approximately 10o to 20o from vertical, and is upwardly rotated 10o to 20o from vertical.

17

BIOMECHANICS

BIOMECHANICS SCAPULOTHORACIC JOINT Normally the scapula rest at a position on the posterior thorax approximately 2 inches from the midline, between second through seventh ribs.

18

The scapula also lies 30o to 40o forward of the frontal plane and in tipped anteriorly approximately 10o to 20o from vertical with a good deal of individual variability. The scapular motions are typically described as if they occur independently of each other. The linkages of the scapula to the SC and AC joints however actually prevents such isolated motion from occurring. The motion of the scapula from this reference position are:1.

Upward / downward rotation (also known as lateral/ medial rotation).

2.

Elevation / depression

3.

Protraction / Retraction (also known as abduction/ adduction).

4.

Anterior / Posterior tipping.

5.

Internal / External Rotation

-

Upward rotation of scapula on thorax during active elevation of the arm increase range of elevation of the arm overhead. Approximately 60o of upward rotation of the scapula on the thorax in typically available. Scapular upward / downward rotation result from a combination of these SC and AC motions.

Upward and downward rotation can also be

described as the referencing movement of inferior angle away from the vertebral column (upward rotation) or movement of inferior angle towards the vertebral column (downward rotation).

19

-

Elevation and depression are translatory motions in which the scapula moves upward (cephalad) or downward (caudally) along the rib cage from its resting position.

-

Protraction and retraction of the scapula on the thorax are often described as translatory motions of the scapula away from or towards the vertebral column, respectively. The scapula follows the contour of the ribs by rotating internally and externally at the AC joint in combination with clavicular protraction and retraction at the SC joint.

-

Internal / External rotation of the scapula on the thorax, accompany protraction / retraction of the clavicle at the SC joint.

-

Anterior / Posterior tipping of the scapula on the thorax occurs at the AC joint and normally will accompany anterior / posterior rotation of the clavicle at the SC joint.

These last two movements are not obvious movement but are unobtrusive motion necessary to maintain the scapula relative flush with the curved rib cage. These motions occur when the range of scapular motion is exhausted or in certain pathological conditions.

Stability Stability of the scapula on the thorax in provided by – 1.

Structures that maintain integrity of the linked AC and SC joints.

2.

Muscles that attach to both the thorax and scapula contact between these surfaces while producing the movements of the scapula. In

20

addition,

stabilization

is

provided

through

scapulothoracic

musculature by pulling or compressing the scapula to the thorax.

STERNOCLAVICULAR JOINT The primary motion at SC joint are – 1.

Elevation and Depression of clavicle.

2.

Protraction and Retraction of the clavicle.

3.

Anterior and Posterior Rotation of the clavicle



Elevation and Depression occur around an approximately anteroposterior (A.P.) axis between a convex clavicular surface and a concave surface formed by the manubrium and the first costal cartilage.



With elevation, the lateral clavicle rotates upward, and with depression, the lateral clavicle rotates downward.



The cephalocaudal shape of articular surfaces and the location of the axis indicate that the convex surface of the clavicle must slide inferiorly on the concave manibrium and first costal cartilage, in a direction opposite to movement of the lateral end of clavicle.



Clavicular elevation-48o



Clavicular depression – less than 15o.

21



Protraction and retraction of the clavicle occur at the SC joint around an approximately vertical (superoinferor) axis that also appears to lie at the costoclavicular ligament.



With protraction, the lateral clavicle rotates anteriorly, and with retraction, the lateral clavicle rotates posteriorly.



Clavicular protraction – 15o – 20o.



Clavicular retraction – 20o – 30o.



Anterior and Posterior rotation occur at long axis, rotation of the clavicle occurs as a spin between the saddle – shaped surfaces of the medial clavicle and manubriocostal facet.



The clavicle rotates posteriorly from neutral, bringing the inferior surface of the clavicle to face anteriorly.



From its fully rotated position, clavicle can rotate anteriorly again to return to neutral.



Clavicular posterior rotation – 50o.



Clavicular anterior rotation – less than 10o.

Stability Stability of SC joint is provided by :

Bony segments of the Sternoclavicular joint.



Capsuloligamentous structure

22



Sternoclavicular disk

ACROMIOCLAVICULAR JOINT The primary rotatory motion at AC joint are 

Internal / External Rotation.



Anterior / Posterior tipping.



Upward / Downward rotation.



Internal / External rotation of the scapula in relation to the clavicle occurs around an approximately vertical axis through the AC joint.



Internal and external rotation at the AC joint bring the glenoid fossa of the scapula anteromedially and posterolaterally, respectively.

 

Internal and External Rotation – 40o – 60o. Anterior / Posterior tipping occur around an oblique “coronal” axis through the joint



Anterior tipping will result in the acromion tipping forward and the inferior angle tipping backward.



Posterior tipping will result in the acromion rotating backward and the inferior angle forward.



Anterior / Posterior tipping – 40o.



Upward / Downward rotation of scapula in relation to clavicle occur about an oblique “A – P” axis approximately perpendicular to the 23

plane of the scapula, passing midway between the joint surfaces of the AC joint. Upward rotation tilts the glenoid fossa upward and downward rotation



is the opposite motion. 

Upward rotation – 30o



Downward rotation – 17o

GLENOHUMERAL JOINT MOTION Primary motion at GH joint are –



1.

Flexion / Extension.

2.

Abduction / Adduction.

3.

Medial / Lateral Rotation Flexion / Extension occur about a coronal axis passing through the center of the humeral head.



Flexion – 120o Extension – 50o

 

Restriction to abduction in medial or neutral rotation is commonly attributed

to

impingement

of

the

greater

tubercle

on

the

corocoacromial arch. When the humerus is laterally rotated 35o to 40o, the greater tubercle will pass under or behind the arch so that abduction can continue.

24

 GH abduction – 90o – 120o.  Medial and lateral rotation occur about a long axis parallel to the shaft of

the humerus and passing through the center of the humeral head. With the arm at side MR and LR may be limited to 60o of combined



motion. Abducting the humerus to 90o frees the arc of rotation with GH values reported to 120o. This restriction to rotation when the arm are at sides may be related to



different alignment of the greater and lesser tubercle, which creates a mechanical block.

Stability In GH joint there are 2 types of stabilizaion – 1.

Static stabilization of GH joint in dependent arm.

2.

Dynamic stabilization of GH joint

Static stabilizationof the GH joint in Dependent Arm

 1.

Magnitude of passive tension in the structures of rotator interval capsule

(Superior

Capsule,

Superior

GH

ligament

and

coracohumeral ligament) that are taut when the arm is at the side, the resultant pull of both the LOG and rotator interval capsule creates a fossa that compresses the humeral head into the lower portion of the glenoid fossa, where the humeral head commonly sits when the arm is at side.

25

2.

GH joint capsule has an airtight seal, which produces negative intra-articular pressure. This pressure creates a relative vaccum that resists inferior humeral translation caused by force of gravity.

3.

A slight upward tilt of the glenoid fossa either anatomically in the structure of the scapula or through scapular upward rotation, the tilt of the fossa will produce a partial bony block against humeral inferior translation.

4.

Resting activity of the supraspinatus and subscapularis also provide static stabilization

Dynamic Stabilization of the GH Joint 1.

Deltoid and Glenohumeral Stabilization

Figure 7. Action lines of deltoid muscle

-

The action lines of the three segments of the deltoid acting together coincide with the fibers of the middle deltoid(Figure 7). When the 26

muscle action line (FD) is resolved into its parallel (Fx) and perpendicular (Fy) Components in relation to the long axis of the humerus, the parallel component directly cephalad (superiorly) is by far the larger of the two components. -

The force (Fx) applied parallel to the long axis of the bone creates a shear force rather then stabilizing effect.

-

Inferior pull gravity cannot offset the Fx component of the deltoid, another force or set of force must be introduced to work synergistically with the deltoid, this is the role of rotator cuff muscles.

2.

Rotator Cuff and Glenohumeral Stabilization

Figure 8. Action lines of rotator cuff muscle -

The supraspinatus, infraspinatus, teres minor, and subscapularis muscles compose the rotator or musculotendinous cuff.

-

The action lines of the four segments of the rotator cuff are –

(i)

Superiorly located supraspinatus

27

-

(ii)

Posteriosly located infraspinatus teres minor

(iii)

Anteriorly located subscapubris muscles.

If any one or all three of the vector pulls of the infraspinatus, teres minor or subscapularis muscles is resolved into its components( Figure 8.), it can be seen that the rotatory force component (Fy) not only tends to cause at least some rotation of the humerus, gives its orientation to the long axis of the bone, but Fy also compresses the head into the glenoid fossa.

-

The sum of the three negative (inferior) translatory components of these muscles of the rotator cuff nearly offsets the superior translatory force of the deltoid muscle.

-

The supraspinatus has a superior translatory component. Its rotatory component is proportionally larger than that of the other rotator cuff muscles making it an effective stabilizer.

- Gravity acts as a stabilizing synergist to the supraspinatus by offsetting the small upward translatory pull of the muscles. (3) The long head of Biceps Brachii and GH stabilization -

Long head of biceps brachii, because of its position at the superior capsule and its connections to structure of rotator interval capsule reinforce cuff of the GH joint.

- Long head appears to contribute to GH stabilization by centering the head in the fossa and by reducing vertical (superior and inferior) and anterior stabilization.

28

SHOULDER COMPLEX MOTION Shoulder complex acts in a co-ordinated fashion to provide the smoothest and the greatest ROM possible to the upper limb. Under normal condition each joint make its contribution not only in a fiercely consistent manner but following a pattern of concomitant and co-ordinated movement known as scapulohumeral rhythm. Scapulohumeral joint contributes to both flexion and abduction of the humerus by upwardly rotating the glenoid fossa 60o from its resting position. Combination of scapular and humeral movement results in maximum range of elevation to 180o and in a overall ratio of 2o of GH and 1o of ST motion(Figure 9).

Figure 9. Scapulohumeral rhythm

Purpose of Scapulohumeral rhythm:1.

Large ROM with less compromise of stability.

29

2.

Optimal position of GH fossa to receive head of humerus increase joint congruence and decrease shear forces.

3.

Maintain length tension relationship of muscle and prevent active insufficiency of GH muscles.

4.

During intial 60o of flexion or initial 30o of abduction of humerus an inconsistent amount of type of scapular motion takes place relative to GH motion. Scapula seeks & position of stability, therefore called setting phase. In this phase motion occurs primarily at GH joint.

Phase One Upper and lower portion of trapezius muscle combine with upper and lower portion of the serratus anterior muscle to produce an upward rotatory force on the scapula. The middle trapezius may also contribute to upward rotation. Although upward rotation of the scapula would appear to occur at the AC joint, the coracoclavicular ligament prevents these AC movement because the ligament bind the coracoid process of the scapula to the clavicle. The upward rotatory force on the scapula from the contracting muscles, therefore must produce movements at the next available joint, SC joint. The pull of trapezius and serretus anterior muscles on the scapula (and the direct pull of the upper trapezius on the lateral clavicle) force the clavicle to elevate.

Clavicular elevation carrier the scapula through 30o of upward

rotation as the scapula rides on the lateral end of the ring clavicle while maintaining a relatively fixed Scapuloclavicular angle.

Elevation of the

clavicle is checked when the costoclavicular ligament becomes taught.

30

Because the ST upward rotation and clavicular elevation occur concurrently with GH motion, the GH joint can be expected under normal condition to simultaneously flex or abduct about 60o (wing an overall 2:1 into with the understanding that individual differences exist). Given 30o of ST upward rotation and 60o of GH flexion & abduction, the arm will be elevated approximately 90o to 100o from the side of the body. During the initial 30o of ST motion, the AC joint maintain a relatively fixed relation between the scapula and clavicle, although 10o of medial rotation and some anterior tipping of the scapula to maintain the scapula against the changing contour of the rib cage.

Phase Two As the lower trapezius and the serratus anterior continue to generate an upward rotatory force on the scapula, upward rotation at the AC joint is still restrained by the coracoclavicular ligament while the SC joint is now constrained by the tension in the coracoclavicular ligament (which checks further clavicular elevation). With no other available motion to dissipate the upward rotatory force being created by the trapezius and serretus anterior (especially the conoid portion) build as the corocoid process of the scapula gets pulled downward. The tensed conoid ligament draw its posteroinferior clavicular attachment forward and down as the

corocoid process drops,

causing the clavicle to posteriorly rotate. Posterior rotation of the clavicle around its longitudinal axis will flap the lateral end of the crank – shaped clavicle up without causing further elevation at the SC joint and while still maintaining a selectively fixed scapuloclavicular angle. The magnitude of posterior rotation of the clavicle may be anywhere from 30o to 50o. The

31

scapula its final position on the rib cage, the AC joint absorbs varying amount of anterior / posterior and medial / lateral rotation. The magnitudes of AC motion can be expected to differ between flexion, scaption, and as direction of the arm, as well as to differ from variations in scapular resting position, rib cage confirmation and muscle dynamics. If 180o is accepted on the maximal range of flexion and abduction of the humerus, ranging the arm to the horizontal involves 60o of GH motion and 30o of ST motion, with the scapular contribution produced by clavicular elevation at the SC joint. Raising the aim from the horizontal to vertical position involves an additional 60o of GH movement (with lateral rotation needed for scaption and abduction) and 30o of ST movement produced by clavicular rotation and AC motion. For the clavicle to rotate about its longitudinal axis, it would appear to require mobility of both the SC and AC joints. However the internal fixation of the AC joint does not significantly impair range of elevation, whereas attempted internal fixation of the SC joint most often result in extension of the fixating harware. These observations would lead. one to conclude that the SC joint is of primary importance both for the first 30o of ST upward rotation with the AC joint playing supporting role. The sequence of phase one and phase two scapulo – humeral motions occurs regardless of the plane in which the arm is elevated. That is although the range may vary somewhat the component event are similar whether the motion is performed as flexion, abduction or scaption of the arm in the frontal plane requires concomitant lateral rotation of the humerus to permit first GH range. There is also another difference between performance of sagittal plane 32

and frontal plane elevation. Although the scapula must upwardly rotate in both stances flexion requires simultaneous protection keeping the fossa in line with the shaft of the humerus. If it did not occur, the head of the humerus would be unprotected posteriorly, posterior dilocation could occur with relatively little force.

In abduction of the arm in the frontal plane, the

scapula tends to remain in neutral protraction – retraction or is slightly retracted.

33

CLASSIFICATION

Classification;

34

dislocation of the sholder may be the of the following type;Anterior shoulder dislocation It may be further classified into three sub types depending on the position of the dislocated head;•

Preglenoid -the head lies in front of the glenoid .

•

Subcoracoid-the head lies below the coracoid process.

•

Subclavicular- the head lies below the clavicle.

o

Arm is held in slight abduction and external rotation.

o

Shoulder is "squared off" (ie, boxlike) with loss of deltoid contour compared with contralateral side.

o

Humeral head is palpable anteriorly (subcoracoid region, beneath the clavicle).

o

Patient resists abduction and internal rotation and is unable to touch the opposite shoulder.

.

Posterior shoulder dislocation In this injury,the head of the humerus comes to lie posterirly,behind the glenoid. o

Arm is held in adduction and internal rotation.

o

Anterior shoulder is "squared off" and flat with prominent coracoid process. Shoulders may look identical in bilateral dislocation, making it a commonly missed injury. 35

o

Posterior shoulder is full with humeral head palpable beneath the acromion process.

o

Patient resists external rotation and abduction.

.

Inferior (luxatio erecta) shoulder dislocation This is rare type where the head comes to lie in the subglenoid position. o

Arm is fully abducted with elbow commonly flexed on or behind head.

Humeral head may be palpable

36

CLINICAL FEATURES

37

Clinical Features

•

Pain. The pain is severe and is located in the region of the affected shoulder following a traumatic first dislocation. This is mainly true of anterior dislocations.

•

Deformity. Anterior dislocations reveal themselves with the obvious lengthening of the arm, and the elongated look of the shoulder. The affected individual will support the afflicted arm.

•

Posterior dislocations do not reveal themselves to well, and one can be lead to think all is well, hence they are are most often upto 80% of times missed until a later date.

•

Bruising. There is a variable amount of bruising but a large bruising should be suspicious of an underlying fracture as well as a dislocation (fracture-dislocation)

•

Numbness/Weakness. There may a weakness of lifting the shoulder and a numbness over the shoulder, for as the shoulder dislocates, it stretches the 'Axillary Nerve', and causes the nerve to disfunction. This usually recovers over the following days to months.

38

INVESTIGATION

39

DIAGNOSIS

PRESENTING COMPLAINTS: The patient enters the casualty with his shoulder abducted and the elbow supported with opposite hand. There is a history of a fall on an out-stretched hand followed by pain and inability to move the shoulder. There may be a history of similar episodes in the past. On examination: The patient keeps his arm abducted. The normal round contour of the shoulder joint is lost, and it becomes flattened. On careful inspection one may notice fullness below the clavicle due to displaced head, which can be felt to rotate by rotating the arm, the following are some signs, associated with anterior dislocation mostly of academic significance: 1. DUGAS TEST: Inability to touch the opposite shoulder. 2. HAMILTON RULER TEST: Because of the flattening of the

shoulder, it is possible to place a ruler on the lateral side of the arm. This touches the acromion and lateral condyle of the humerus simultaneously. 3. CALLWAY’S TEST: In dislocation of the shoulder, vertical circumflex of axilla is increased compared to the normal side. The diagnosis is easily confirmed on an anterior-posterior X-ray of the shoulder. An axillary view is sometimes required.

40

41

TESTS FOR ANTERIOR SHOULDER INSTABILITY Load and shift testThis test is designed to test primarily atraumatic instability problems of the glenohumeral joint.(A) Initial position for load and shift test for anterior instability testing of the shoulder in supine lying position. The examiner’s hand grasps the patient’s arm and controls its rotation. The arm is placed in the plane of the scapula, abducted 45o to 60o and maintained in 0o of rotation. The examiner’s fingers then shift the humeral head anteriorly, and anteroinferiorly over the glenoid rim. (B) The examiner quantifies the degree of lateral rotation required to reduce the translation from grade 3 or 2 to grade 1. The examiner compares the normal and abnormal shoulders for this difference in translation with the humeral rotation. The degree of rotation required to reduce the translation is an indicator of the fuctional laxity of the anterior inferior capsular ligaments. Apprehension (Crank) Test for Anterior shoulder Dislocation. This test is primarily designed to test for traumatic instability problems causing gross or anatomical instability of the shoulder. The examiner abducts the arm to 90o and laterally rotates the patient’s shoulder slowly. A positive test is indicated by a look or feeling of apprehension or alarm on the patients face and the patients resistance to further motion. If the abduction and lateral rotation combined with posterior translation of the humerus called relocation test.

42

Rowe test for anterior instability The patient lies supine and places the hand behind the head. The examiner places one hand (clenched fist) against the posterior humeral head and pushes up while extending the arm slightly. A look of apprehension or pain is indicative of a positive test for anterior instability. If a clunk or grinding sound is heard when doing the test, it may indicate a torn anterior labrum. Anterior Drawer Test of the shoulder The patient lies supine. The examiner places the hand of the affected shoulder in the examiner’s axilla, holding the patient remains relaxed. The shoulder to be tested is abducted between 80o and 120o, forward flexed up to 20o, and laterally rotated up to 30o. The examiner then stabilizes the patient’s scapula with the opposite hand, pushing the spine of the scapula forward with the index and middle fingers. The examiner’s thumb exerts counterpressure on the patient’s coracoid process.using the arm that is holding the patients hand, the examiner places his or her hand around the patient’s relaxed upper arm and draws the humerus forward. The movement may be accompanied by a click or by patient apprehension or both.

43

Tests for posterior shoulder instability;Load and shift test:-This test is described under anterior shoulder instability.

Posterior apprehension or stress test;-the patient is in supine lying position. The examiner elevates the patients shoulder in the plane of the scapula to 90 degree while stabilizing the scapula with the other hand. The examiner then applies a posterior force on the patients elbow. While applying the axial load, the examiner horizontally adducts and medially rotates the arm. a positive result is indicated by a look of apprehension or alarm on the patient face and patient’s resistance to further motion or the patient’s symptoms. Posterior drawer test of the shoulder ;The patient lies supine.examiner stands at shoulder level of patient. And grasp s the patient’s forearm with one hand,flexing the patient’s elbow to 120degree and the shoulder to between 80 degree and 129 degree of abduction and between 20 to 30 degree of forward flexion. With the other hand, the examiner stablizes the scapula by placing the index and middle fingers on spine of the scapula and the thumb on the coracoid process ( the examining

44

table partially stabilizes the scapula as well ). The examiner then rotates the upper arm medially and forward flexes the shoulder to between 60 degree and 80 degree while at the same time taking the thumb of the other hand off the corcoid procees and pushing the head of humerus posteriorly .The head of the humerus can be felt by the index finger of the same hand. The test is usually pain free, but the patient may exhibit apprehension. A positive test is indicative of posterior instability and demonstrates significant posterior translation ( >50% humeral head diameter).

45

Test for inferior and multidirectional shoulder instability :Test for inferior shoulder instability ( sulcus Sign). The patient stands with the arm by the side and shoulder muscles relaxed . The examiner grasps the patient’s forearm below the elbow and pulls the arm distally. The presence of a sulcus sign may be indicative of inferior stability or glenohumeral laxity.A bilateral sulcus sign is not as clinically significant as unilateral laxity on the affected side.The sulcus sign with a siling of subluxation is also significant. It has been reported that the best position to test for inferior instability is 20 degree to 50 degree of abduction with neutral rotation. Also , rotation will cause the capsule to tighten anteriorly ( lateral rotation ) or posteriorly and the sulcus distance will decrease. Thus, more than one position should be tested. Feagin test.; The feagin test is a modification of the sulcus sign test with the arm abducted to 90 degree instead of being at the side. The patient stands with the arm abducted to 90 degree and the elbow extended and resting and top of the examiner shoulder the examiner hands are clasped together over the patients humerus, between the upper 46

and middle thirds. The examiner pushes the humerus down. Doing the test this way often give the examiner greater control when doing the test . a sulcus may also be seen above the coracoid process. A look of apprehension on the patient face indicate a positive test and the presence of anteroinferior instability

.

47

TREATMENT

48

TREATMENT CONSERVATIVE MANAGEMENT Treatment consists of reduction under sedation or general anaesthesia,followed by immobilization of the shoulder in a chest-arm bandage for three weeks. After the bandage is removed , shoulder exercises are begun.

TECHNIQUES OF REDUCTION OF SHOULDER DISLOCATION KOCHER’S MANOEUVRE: This is the most commonly used method . The steps are as follows: (1) Traction- with elbow flexed to a right angle steady traction is applied along the long axis of the humerus (2) External Rotation- the arm is rotated externally (3) Adduction-the externally rotated arm is adducted by carrying the elbow across the body towards the midline (4) Internal Rotation- the arm is rotated internally so that the hand falls across to the opposite shoulder

HIPPOCRATES MANOEUVRE: In this method , the surgeon applies a firm and steady pull on the semi-abducted arm. He keeps his foot in the axilla against the chest wall. The head of humerus is levered back into the position using the foot as the fulcrum.

49

A fracture of the greater tuberosity ,often associated with an anterior dislocation usually comes back to its position as the head is reduced and needs no special treatment.

SURGICAL TREATMENTThe following operations may be considered: a) Putti platt operation: Double breasting of the subscapularis tendon is

performed in order to prevent external rotation and abduction,thereby preventing recurrences. b) Bankart’s operation: The glenoid labrum and glenoid rim. This is a

technically demanding procedure, but has become simpler with the use of Anchor sutures. c) Bristostows operation: In this operation, the coracoid process, along

with its attached muscles, is osteotomised at its base and fixed to lower half of anterior margin of the glenoid. The muscles attached to the coracoid provide a dynamic anterior support to the head of the humerus. d) Arthroscopic

Bankarts repair : With the development of

arthroscopic techniques it has become possible to stabelise a 50

recurrently unstable shoulder arthroscopically. Cases where the number of dislocations has been less then 5 from the ideal cases for such a treatment. Apart from being a more cosmetic option, the rehabilitation after arthroscopic repair is faster and better. It is a technically demanding operation and the sutures used for repair are expensive. This technique is available only in selected centres.

51

PHYSIOTHERAPY MANAGEMENT TREATMENT OF SUBCORACOID ANTERIOR DISLOCATION OF SHOULDER The dislocation is reduced by manipulation either by sedation or under general anaesthesia. The reduction is maintained by immobilizing the limb in adduction and internal rotation with the hand of the affected side close to opposite shoulder. The immobilization is secured by strapping the arm in the trunk. The immobilization should be maintained for the period of 3 weeks .This provides adequate healing time for the tear in the anterior capsule of the shoulder joint through which the head had dislocated . It is an accepted fact that adequate immobilization after the initial injury eliminates the possibility of recurrence . PHYSIOTHERAPY MANAGEMENT BASIC OBJECTIVE:

To regain full range active movements of the

shoulder complex with an emphasis on the early return of movements of abduction and external rotation. DURING IMMOBILISATION ( first 3 weeks) As the arm is strapped to the trunk in a position of adduction and internal rotation, only wrist and finger movements are possible. Full range strong resistive movements at theses joints should be practised at regular intervals. Self resistive.isometric

contractions can safely be instituted to the

deltoid ,biceps and triceps. 52

MOBILISATION ( AFTER 3 WEEKS) After the removal of the strapping the limb is supported in a sling. Elbow should be immobilised

to the full extent by removing the sling

intermittently. Mobilization of the shoulder flexion-extension should be initiated as small range pendular swinging movements in a forward stoop position. These movements are to be carried out with arm within the sling. However, sling could be loosened to accommodate greater range of motion . Initiation of shoulder abduction and external rotation. As these two movements are instrumental in causing redislocation they have to be initiated with utmost care and adequate stabilization at gleno-humeral joint. Relaxed passive abduction up to 45 degrees should be the initial aim. It is done with the patient in supine lying, the physiotherapist passively performs the arc of abduction with the arm in internal rotation. External rotation should be initiated in the same position and by the same technique. It should be done with the arm adducted by the side of the body.

53

As it is important to avoid secondary adhesive capsulitis, relaxed passive movements to the shoulder be carried out to the full or near normal range at the earliest. Self-assisted relaxed movements with wand in supine lying are also helpful at this stage.

54

Once a good passive range is attained, regime of strengthening is begun. Self-resisted isometric and slow isotonic movements to be taught as a home treatment programme. Resistive devices like dumbells could be used in the department. The programme should be monitored at regular intervals to ensure that 90 percent of the full range is achieved by 6-8 weeks following dislocation. Heavy resistive exercise, passive stretching and forced external rotation and abduction are safe after 12 weeks. It may be difficult in some patients to achieve the terminal range of abduction-elevation and external rotation. This could be painful and needs to be facilitated by a suitable thermotherapy adjunct. Majority of patients regain full function by 12 weeks following the injury. COMPLICATIONS 1. Fracture of the greater tuberosity or surgical neck of the humerus. 2. Supraspinatus tendonitis 3. Rotator cuff injury 4. Recurrent anterior dislocation of shoulder 5. Injury to the axillary nerve

55

POSTERIOR DISLOCATION This injury is caused by forceful internal rotation of the shoulder ,e.g. during electroconvulsive therapy or epileptic attack or severe electrical shock.

TREATMENT Reduction of the dislocation by manipulation. The limb is immobilized in a sling for 2-3 weeks. PHYSIOTHERAPY MANAGEMENT The treatment objective and the treatment approach basically remain the same as described for the anterior dislocation of the shoulder. The only difference being the utmost care while carrying out the movement of adduction and internal rotation. The movement of adduction should be done with shoulder in external rotation and the movement of internal rotation should be done with shoulder in abduction. Patients need to be cautioned against performing these movements either simultaneously or separately with jerk.

56

57

RECURRENT ANTERIOR DISLOCATION OF THE SHOULDER Recurrent anterior dislocation of the shoulder occurs due to the failure of healing of torn or avulsed capsule from its anterior glenoid attachment . Lateral rotation is the most persistent cause of this , which allows the defect to open and the head of humerus slips anteriorly . It is a common phenomenon accounting for more than 80 % of dislocation of the upper extremity. TREATMENT The treatment in variably is surgical. Although a large number of surgical operations are performed most commonly : 1. Bankart’s operation : The tear in the anterior capsule is repaired and

the avulsed part of glenoid labrum is re-attached. 2. Putti-Platt operation: In this operation the subscapularis muscle is

divided along with the anterior capsule and it is sutured back by overlapping (doublebreasting) both the divided edges of the subscapularis muscle along with the capsule . Postoperatively the limb is immobilized in internal rotation by the side of trunk for a period of 3 weeks, after which the shoulder is mobilized. PHYSIOTHERAPY MANAGEMENT Physiotherapy can play a very important role in preventing recurrent anterior dislocation of the shoulder. 58

Preventive regime of physiotherapy The principal objectives of physiotherapy are: 1. To strengthen the ligaments and muscles crossing the shoulder joint to the optimum level. 2. To regain full passive ROM of all the movements. Physiotherapy regime involves hard conscientious efforts for a long time and extra cation to avoid recurrence of dislocation. Therefore, proper selection of the patient is very important. Strengthening procedure. To be successful, it needs several repetitions. The best approach is to teach the patient self-resisted eccentric, as well as isometric contractions (reversal technique) for all the shoulder movements. The exercises should be taught in standing or sitting so that they can be conveniently performed several times. Self-resisted small range reversal technique for various agonists and respective antagonist groups is very well accepted by the patient. In the department , weighted dumbbells, or weight belts may be used so that the progress and the extent of muscular strength can be assessed and monitored at regular intervals. To achieve and maintain full range passive motion. Initially it has to be done by a physiotherapist with the patient in supine. The arc of movements of abduction-elevation,flexion-elevation and external rotation need to be done gradually and carefully.To assure total relaxation it is ideal to use some 59

thermotherapy or cryotherapy adjunct before initiating these movements. Once the near-normal or full range is achieved, the patient is taught to carry out these movements. Extra care should be taken during the terminal range of elevation and external rotation. As adequate stabilization of the shoulder-girdle facilitates relaxation or the gleno-humeral joint, the patient should be advised to get some assistance at home while performing these movements. However , proper guidance to stabilize the shoulder girdle has to be learnt from the physiotherapist before carrying it out at home. For the success of this regime of prevention, long standing efforts(3 to6 months) and skilful education of the patient are essential. Surgically managed patients The regime of physiotherapy for the patient treated with surgery proceeds on the same lines as described for the “anterior dislocation”. The main difference being the secured safety of performing the movements.The joint is stable as the head of the humerus is enveloped firmly by overlapping of the divided parts of subscapularis. Therefore, passive sustained stretching is safe. But , it needs hard efforts to achieve active terminal range of elevation and external rotation. Usually the extreme range of external rotation remains deficient. However , a strong and functional shoulder can be achieved within 10=12 weeks. On the whole the results are excellents.

GUIDELINES FOR SHOULDER REHABILITATION 60

- Make a complete & accurate diagnosis - Early pain reduction - Scapular stabilization Early achievement of 90o of abduction

-

- Closed chain rehabilitation - Plyometric exercise - Rotator cuff exercise - Integration of kinetic chain into rehabilitation

1) Make a complete & accurate diagnosis Many times diagnosis of shoulder injuries is incomplete due to a number of factors that combine to influence shoulder fuction. The diagnosis must not only include the local anatomical deficits such as rotator cuff tera,labral injury or fracture but also local biomechanical deficits. These includei)

inflexibility of internal or external rotators

ii)

force couple imbalance of internal or external rotators

Finally, distinct deficits such as back &hip inflexibility injuries or strength imbalances should be evaluated.

2) Early pain reduction

61

Pain is a cause of altered shoulder function. Avoidance of painful positions causes the athlete to assume abnormal positions of the arm. Pain also creates a high degree of muscle inhibition which alter muscle firing pattern. Treatment- pain should be controlled by relative rest of the area or decresed throwing activities. - avoidance of painful arcs of motion. - Cryotherapy - Ultrasound - Infection into the subacromial space - NSAIDS - Analgesics - Exercise should be kept with in pain free range. 3) scapular stabilization The scapula is the base upon which all shoulder activities rest. The four main roles of scapula include i)

retraction & protraction in different phases of throwing motion.

ii)

Elevation of acromion in abduction of the arm

iii)

Acting as a socket for GH joint

iv)

Acting as a base of origin for the muscle of rotator cuff, deltoid, biceps & triceps.

Treatment- assess the motion & position of the scapula in various phases of throwing motion & also assess muscular strength & scapular stabilization.

62

- most of the scapular control exercises are done through the method of closed chain rehabilitation. Eg- scapular retraction – push up-resistance a medial side of scapula by physiotherapist.

4) Early achievement of 90o of abduction Most throwing activity in sports demands 90o of shoulder abduction as throwing activities occur between 85o & 110o of abduction. Treatment- pain should be decresed from impingement or other sources as quickly as possible. - maintain scapular stabilizer strength so that acromial elevation clears the acromion fron the rotator cuff. -

When performing surgical reconstruction for shoulder stability, the surgeons must ensure that 90o of abduction can be obtained on the operating table this will allow early achievement of 90o of shoulder abduction & undue stress on shoulder.

Specific exercise to achieve 90o of abduction include-active assisted exercise -gentle joint mobilization -passive stretching 5) closed chain rehabilitation

63

The predominal method of muscle activation around the shoulder articulation is a closed chain activity & emphasing co-contraction at the scapulo-thoracic & GH joint. This result in proper scapular stability. Open chain activities which involve agonist antagonist force couple &generate force for the shoulder & kinetic chain are also done around the shoulder. Treatment-the exercise started at levels below 90o of abduction in early phase of rehabilitation to allow for healing of tissues. -the hand is placed against some object such as a table, a ball, or the wall. Eg for closed chain exercise i)scapular retraction ii)scapular elevation iii)wall push ups iv)knee push ups

6)Plyometric exercise Plyometric activities develops the patients activity to generate the power by producing a stretch shortening cycly in which the muscle is eccentrically stretched followed by rapid concentric contraction. - Plyometric should be done for all body segments involved. - Plyometric activities for lower limb can be done in early phases of rehabilitation but plyometric exercise for upper limb should be instituted in later phase. 64

Eg rubber tubing exercise, balls are also excellent plyometric devices.

7) Rotator cuff exercise Rotator cuff muscles are very important in maintaing the humeral head into the glenoid socket. Rotator cuff muscles should be rehabilitated as an integrated unit rather than as individual muscle. They do not work in isolation in shoulder fuction. Early rotator cuff exercise should be done in a closed chain fashion. This allows rotator cuff strengthening with out including shear on the joint. If rotator cuff deficits are still observed in later phases of rehabilitation, isolation rotator cuff exercise can be administered. 8) Integration of kinetic chain into rehabilitationRe-establish the kinetic chain early in the rehabilitation process. While the shoulder is recovering from injury or syndrome. Leg & trunk muscles can be prescribed some exercise so that when the shoulder is ready for rehabilitation the base link activity. Endurance activities in legs shoulder also be emphasized.

65

66