In this section it will be also including fractures scapula and acromioclavicular joint injuries beside shoulder dislocation or subluxation what are the difference between dislocation and subluxation  dislocation means complete separation while subluxation mean partial separation
shoulder dislocations can be divided into the following types 1- anterior dislocation 2- posterior dislocations 3- chronic dislocations 4- recurrent dislocations 5- inferior dislocations 


The shoulder joint consists of three bones which are the scapula clavicle and humerus they are articulated to form two separated joints which forming  shoulder joint the acromioclavicular joint between acromion process of the scapula and lateral end of the clavicle and genohumeral joint between round head of the humerus or upper arm bone and glenoid fossa of the scapula

Acromioclavicular joint injuries

Disruption of the AC joint is a relatively common injury and is typically seen in young males. It is usually caused by trauma,
commonly sporting injuries, and is associated with superior sub­luxation or dislocation of the lateral end of the clavicle .

Classification Rockwood classification

Type I - the capsule and coracoclavicular ligaments are damaged but not ruptured. and no subluxation of the joints occurs.

Type 2 - the joint is subluxed, with some superior displace­ment of the clavicle: this is associated with increased damage to but not rupture of the ligaments.

Type 3 - the ligaments are ruptured and the clavicle dislo­cates superiorly.

Type4 - the lateral end of the clavicle dislocates and lies subcutaneously due to severe soft-tissue injury.

Type 5 - the clavicle dislocates and lies posterior to the acromion rare.

Type 6 - the clavicle dislocates and lies inferior to the acromion rare.


Most injuries can be treated conservatively, with good results expected. A broad arm sling can be used. with mobilisation as comfort allows. In certain circumstances. early surgery may be indicated, especially for the less common type 4-6 injuries. Late reconstruction of the AC joint is occasionally required for persis­tent displacement of the clavicle associated with pain and func­tional impairment.

Scapular fractures

These are uncommon injuries and are usually caused by direct trauma, often due to road traffic accidents. Most can be treated conservatively, Internal fixation is indicated for some articular fractures of the glenoid.

A glenoid fracture usually represents a fracture dislocation of the shoulder. The size and displacement of the fragment must be assessed and this can be done by computerised tomography. Conservative treatment with immobilisation will be required for minimally displaced fractures. although rarely for more than 3 weeks. Indications for internal fixation. usually by a lag screw technique. include large displaced fragments and an unstable shoulder. Operative approach, method of fixation and postopera­tive mobilisation will be determined by the fracture pattern and fixation achieved at surgery.

Anterior shoulder dislocations

Dislocation of the glenohumeral Joint

The glenohumeral joint is the most commonly dislocated large joint in the body. The humerus can dislocate anteriorly, posteriorly, or inferiorly relative to the glenoid. Anterior dislocations are by far . the most common, accounting for more than 95% of cases. They generally occur after an indirect trauma with the arm abducted, externally rotated, and extended. Anterior dislocations often cause a tear in the glenoid labrum (Bankart lesion) and also can cause a compression fracture of the posterolateral aspect of the humeral head by the glenoid rim (Hill-Sachs lesion). When one of these occur, the patient usually develops recurrent dislocations of their shoulder.

Approximately45% of all joint dislocations in adults occur at the glenohumeral joint.   The injury is therefore more common in males in the age group 21-30. although glenohumeral dislocation does occur in elderly females. In this age group rotator cuff dam­age may occur in association with the dislocation Patients present with a painful shoulder held in slight external rotation and abduction. Physical examination may show squaring off of the shoulder with loss of the deltoid prominence, as well as fullness anteriorly, where the humeral head is situated. There is minimal active motion of the shoulder. A neurovascular exam should be performed. Sensation over the lateral deltoid region must be assessed, because the axillary nerve is the most common nerve injured. Anteroposterior, scapular Y, and axillary radiographs are obtained. Radiographs will demonstrate the anterior dislocation and any associated fractures of the proximal humerus or glenoid .

Reduction of the dislocated shoulder should be performed expeditiously. Narcotic analgesics and sedatives are usually necessary to facilitate reduction. Numerous reduction maneuvers have been described, but these of the more commonly used techniques are the Stimson technique or hanging arm and the Hippocratic technique and kocher technique. The Stimson technique involves placing the patient prone with the involved arm hanging off the side of the table . Traction is applied by hanging /weights from the patient's wrist. The patient must relax. Usually the shoulder reduces quickly, but it may take 15 minutes before the tensed shoulder muscles fatigue and allow the shoulder to reduce. In the Hippocratic technique, longitudinal traction is applied with the arm slightly abducted. Countertraction is applied in the axillary region, either with one's foot as originally described by Hippocrates or by an assistant holding onto a sheet wrapped around the patient's chest. If the reduction cannot be obtained, closed or possibly open reduction may be required in the operating room. This is particularly true with chronic dislocations. Radiographs are repeated after reduc­tion to ensure the shoulder is reducedThe patient is immobilized in a sling and swathe. Older patients are prone to develop shoulder stiffness so passive range-of-motion. along with isometric exercises, is begun in 1 to 2 weeks. Rotator cuff tears are a common associated injury after shoulder dislocation in elderly patients. Slow progress with rehabilitation in this group should prompt one to evaluate for a cuff tear, because surgical cuff repair may be beneficial. Young patients are at risk for redislocation so they are kept immobilized from 3 to 4 weeks. Redislocation is the most common complication after shoulder dislocation. the age of the patient is the most important factor, with recurrence rates as high as 80 to 90% in patients younger than age 20 years, and as low as 10 to 15% in patients older than age 40 years. Young athletes in contact sports are at particularly high risk for redislocation and arthroscopic stabilization with repair of the bankart lesion should be considered after a shoulder .
Dislocation is frequently associated with damage to the gle­noid labrum and detachment of the anteroinferior segment, the Bankart lesion. In addition, damage to the back of the humeral head can occur as a Hill-Sachs lesion . Both of these abnormalities predispose to recurrent dislocation. Less than 5% of primary dislocations are posterior.

The dislocation should be reduced as early as possible and this can usually be accomplished under sedation. There are three in common methods of reduction dislocations . Following reduction, the arm is rested in a sling for approximately one week and mobilisation commenced. Prolonged immobilisation, as previ­ously recommended. does not seem to influence the recurrent dis­location rate.
Summary of reduction of traumatic anterior shoulder dislocations
Three methods of reduction and should be performed as soon as possible
Hippocratic- the arm is pulled down then the toe used to guide in the humeral head

Kocher- the elbow is flexed, arm adducted then internally rotated
hanging arm patient leaves arm hanging down with a weight attached
Hippocratic method The patient lies supine on a bed, although classically the patient lies on the ground. Traction is applied to the arm with the elbow extended and the arm is flexed and abducted at the shoulder. As traction is continuously applied, the humeral head is eased back into the joint by the surgeon's stockinged foot.

Kocher's method Traction is applied to the arm. with the elbow flexed to 90 degree. The arm is slowly externally rotated, and then internally rotated and flexed across the body to reduce the shoul­der. This may be modified by abducting as well as externally rotat­ing the arm, and a collar and cuff bandage can be used to provide counter-traction over the humeral head. All these manoeuvres should be carried out gradually as spiral fractures of the humerus and brachial plexus injuries have been respond.

Hanging-arm method This method may be tried without sedation. The patient is placed face down on a bed or bent over a chair. The arm is allowed to hang free, with the elbow extended; an intravenous fluid bag can be tied to the arm to provide trac­tion. 

Posterior shoulder dislocations

Posterior shoulder dislocations can occur as a result of direct trauma to the anterior humerus or indirectly from seizures or electric much less common and has been associated with epilepsy and electrocution. The humeral head appears light-bulb shaped on anteropos­terior radiographs, an appearance that is normally seen on a lateral or an axillary view Patients present with pain, the shoulder held in internal rotation, and adduction. The injury is frequently not recognized in the emergency room. Physical findings include a prominent coracoid process, full­ness of the posterior shoulder, and limited external rotation and elevation of the shoulder. Anteroposterior, scapular Y, and axillary radiographs are obtained. The dislocation may be missed on the anteroposterior radiograph because the findings are subtle. the standard axillary view best demonstrates the dislocation , but may be difficult to obtain because of the patient discomfort with shoulder abduction. In this case, a modified axillary view, such as the Velpeau axillary lateral view, should be obtained.
Associated fractures, including a reverse Hill-Sachs lesion (com­pression fracture of the anteromedial humeral head caused by the posterior glenoid rim). should be noted on the radiographs.

Reduction is performed using the Hippocratic technique with longitudinal traction. After the reduction is obtained and confirmed with repeat radiographs, the shoulder is immobilized for 3 to 4 weeks in a shoulder spica cast, with the shoulder in neutral rotation and slight abduction and extension

    Chronic shoulder Dislocation

If a shoulder joint has been dislocated for a few days, it becomes much harder to reduce by closed techniques. Open reduction is the only means to reduce the shoulder joint in this circumstance. How­ever, this procedure may be extremely difficult, particularly if several weeks have elapsed from the time of injury. The dislocation causes the anatomy to be distorted and the neurovascular structures may be bound down in scar tissue. In elderly patients with low functional demands and minimal pain with a chronic shoulder dislocation, conservative treatment leaving the shoulder joint dislocated
may be the best option

Recurrent shoulder dislocations

This is age related and is usually due to the presence of a bankart lesion in the under 25 years approximately 60% will have further instability and approximately half of these will require surgery only 25% of the over 35 years age group will have further problems

Complications of shoulder dislocations

Nerve palsy Neurological dysfunction is common after shoulder dislocation and electrophysiological tests have revealed abnormalities in over half of the patients . Significant prob­lems occur in approximately 5% of patients. with the axillary
nerve, or occasionally the suprascapular nerve, involved. The majority of palsies recover with conservative treatment.
This is age related and is usually due to the presence of a Bankart lesion. In the under-25 years approximately 60% will have further instability and approximately half of these will require surgery. Only 25% of the over 34 age group will have fur­ther problems. Instability of the glenohumeral joint is considered in more detail in the previous section of diseases of shoulder joint .

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