Sternoclavicular joint injury is quite rare and results from direct or indirect force on the sternoclavicular joint. The sternoclavicular joint is a saddle-type joint that provides free movement of the clavicle in nearly all planes especially ability to thrust the arm and shoulder forward. Sternoclavicualr joint has little inherent stability but is supported by strong joint capsule ligaments. The capsule surrounding the joint is weakest inferiorly. Ligaments of the joint include the interclavicular, anterior and posterior sternoclavicular, and costoclavicular ligaments.
Sternoclavicular injuries are rare. The literature quotes incidence to be 3%. Anterior dislocations of the sternoclavicular joint are much more common than are posterior ones. The ratio of anterior dislocations to posterior dislocations of the sternoclavicular joint of approximately 20 to 1.
Anterior dislocations of the sternoclavicular joint result in less morbidity [pain, functional limitations, cosmetic issues] whereas a posterior dislocation has the potential for severe and even life-threatening complications like lung injury ( hemothroax, pneumothorax, tracheal injury, neurovascular injury and esophageal injury.
Incidence is increased in young adult males.
Mechanism of Sternoclavicular Joint Injury
A traumatic dislocation of the sternoclavicular joint usually occurs only after tremendous forces, either direct or indirect, have been applied to the shoulder.
When a force is applied directly to the anteromedial aspect of the clavicle, the clavicle is pushed posteriorly behind the sternum and into the mediastinum resulting in posterior dislcation/.
A force act indirectly on the sternoclavicular joint from the anterolateral or posterolateral aspects of the shoulder. This is the most common mechanism of injury to the sternoclavicular joint.
If the shoulder is compressed and rolled forward, an ipsilateral posterior dislocation results. If the shoulder is compressed and rolled backward, an ipsilateral anterior dislocation results.
Causes of Sternoclavicular Joint Injury
Motor vehicle accidents are the most common mechanism producing sternoclavicular dislocation.
Fall on an outstretched abducted arm, driving the shoulder medially may also result in sternoclavicualr joint injury.
Dislocations of the sternoclavicular joint also may result from congenital, degenerative, and inflammatory processes.
Patients with ligamentous laxity may be prone to this injury.
One of the most common causes of injury is a pile-on in a football game. A player falls on the ground, landing on the lateral shoulder and several players pile on top of his opposite shoulder, which applies significant compressive force on the clavicle down toward the sternum.
Other types of indirect forces that can produce sternoclavicular joint injury are
- A cave-in on a ditch digger
- A person is pinned between a vehicle and a wall
- Fall on the outstretched abducted arm, which drives the shoulder medially
The most common cause of dislocation of the sternoclavicular joint is vehicular accidents folllowed by sports.
Classification of Sternoclavicular Joint Injury
Mild Injury- Sprain
Mild injury is equivalent to sprain.
The ligaments of the joint are intact. There is mild to moderate amount of pain, particularly with movement of the upper extremity. The joint may be slightly swollen and tender to palpation, but instability is not noted.
Moderate Injury- Subluxation
A moderate injury results in a subluxation of the sternoclavicular joint. The ligaments are either partially disrupted or severely stretched. Swelling and pain is marked, particularly with any movement of the arm. Anterior or posterior subluxation may be obvious to when the injured joint is compared with the normal sternoclavicular joint.
Severe Injury- Dislocation
It is analogous to a joint dislocation. The dislocation may be anterior or posterior. The capsular ligament and the intraarticular disk ligament are ruptured.
Atraumatic Subluxation and Dislocations
Atraumatic subluxation and dislocations are usually anterior and are usually painless.Patient raises the arm forward, the medial clavicle spontaneously displaces anteriorly and superiorly, and there is a reduction of the medial clavicle on lowering the arm
Patients typically present with their head tilted toward the affected side and complain of chest and shoulder pain exacerbated by arm movement or in supine position.
The patient may complain of difficulty in swallowing or a tight feeling in the throat or may be in a state of complete shock or possibly have a pneumothorax.
Pain tends to be more severe with posterior dislocations. Symptoms like dyspnea, dysphagia, extremity swelling and paresthesia.
The affected shoulder usually appears shortened and thrust forward.
In patient with suspected sternoclavicular joint injury, tachypnea, stridor, hoarseness and other signs of respiratory distress should be carefully noted. Neurovascular adequacy should be checked.
Physical findings at the may be more subtle with posterior dislocations.
Radiological imaging is very important part of diagnosis making of sternoclavicular injuries. In addition to routine xray views, special views have been developed to confirm the injury.
Anteroposterior x-rays of the chest or sternoclavicular joint may show sternoclavicular joint displaced as compared with the normal side. Lateral x-rays are difficult to interpret due to overlapping of structures.
Special xrays for better visualization are
Patient is in supine position, the x-ray tube is placed approximately 30 inches from the involved sternoclavicular joint and the central ray is directed tangential to the joint and parallel to the opposite clavicle. The cassette is placed against the opposite shoulder and centered on the manubrium.
The patient is seated at the x-ray table,leaning forward in a way that the nape of his flexed neck is almost parallel to the table and lower anterior rib cage against the cassette on the table. The x-ray source is above the nape of the neck.
The patient is positioned on his back and the tube is tilted at a 40-degree angle off the vertical centering over sternum with cassette under patient’s upper shoulders and neck.
In children, the distance from the tube to the cassette is 45 inches and in adults 60 inches.
If the sternoclavicular joint is dislocated anteriorly, the affected clavicle will appear to be displaced and riding higher. If it is dislocated posteriorly, it will appear to be lower.
CT scan is the best modality to study the sternoclavicular joint injury. it helps to distinguish articular injuries of the joint from fractures of the medial clavicle.
Other imaging studies, such as angiography or esophagoscopy may be needed in posterior dislocations.
Non operative treatment includes analgesic medication and other supportive treatments.
Anterior Sternoclavicular Joint Injury
In mild injury the sternoclavicular joint is stable but painful. Apply ice for the first 12 to 24 hours. Then immobilize the upper limb. The immobilization should continue for 4 days to one week. Following that the limb should be gradually used in day to day activities.
For subluxation of the sternoclavicular joint, application of ice is recommended for the first 12 hours, followed by heat for the next 24 to 48 hours. The subluxed joint can be reduced by drawing the shoulders backward as done in reduction of fracture of clavicle.
A clavicular immobilizer is used to hold the reduction. Alternatively, a figure of 8 bandage can be used.
Severe injury means dislocation. Non operative treatment can be successful but often when it fails, these dislocations are treated with operative procedures to repair or reconstruct the joint. But it is important to attempt closed reduction first
For closed, under local or general anesthesia or sedation, the patient is placed supine on the table. Keep a thick pad between the shoulders. Reduce the joint with direct gentle pressure over the anteriorly displaced clavicle while an assistant pushes both the shoulders back to table. After reduction, the shoulders should be held back for 4 to 6 weeks with a figure-of-eight dressing. Gradual mobilization is begun after that.
Posterior Sternoclavicular Joint Injury
Posterior sternoclavicular joint injury is more dangerous than anterior sternoclavicular injuries. They should be carefully evaluated for severity before deciding in favor of nonoperative treatment.
Mild to Moderate Injury (sprain, Subluxation)
The ligaments remain intact and there is moderate discomfort to the patient. There may be swelling and tenderness. Careful examination and evaluation must be done to rule out posterior dislocation. It is best to protect the sternoclavicular joint with a figure-of-eight bandage for 2 to 6 weeks.
Severe Injury (Dislocation)
Poserior sternoclavicular injury is a dangerous injury. The damage to the structures posterior to the joint, like the trachea, esophagus, the brachial plexus, great vessels, the lungs must be carefully noticed.
A detailed physical examination must be done and special radiographs must be obtained. CT scan of both medial clavicles allows the physician to compare the injured side with the normal side. Arteriogram of the vessels is needed if vascular injury is suspected.
A nonoperative approach should be strongly considered especially in young adults.
A general anesthesia is usually required for reduction of a posterior dislocation of the sternoclavicular joint because of pain and muscle spasms. Intravenous narcotics and muscle relaxants may be considered for patient who have high threshold of pain.
Closed reduction should preferably be done within 48 hours.
Many different techniques have been described for closed reduction of a posterior dislocation of the sternoclavicular joint.
Abduction Traction Technique
The patient is placed on his back with the dislocated shoulder near the edge of the table. A thick sandbag is placed between the shoulders.
Lateral traction is applied to the abducted arm, which is then gradually brought back into extension. The clavicle usually reduces with an audible snap or pop, and it is almost always stable.
Occasionally, it may be necessary to grasp the medial clavicle with one’s fingers to dislodge it from behind the sternum.
If this fails, a sterile towel clip is used to grasp the medial clavicle to apply lateral and anterior traction after skin preparation.
Adduction Traction Technique
The patient is placed supine on the table with a 3- to 4-inch bolster between the shoulders.
Traction is then applied to the arm in adduction, while a downward pressure is exerted on the shoulder.
The clavicle is levered over the first rib into its normal position.
Heinig and Elting Technique
Place the patient supine on the table with three or four folded towels between the two shoulders. Forward pressure is then applied on both shoulders, which accomplished the reduction.
The shoulders should be kept in figure-of-eight dressing or clavicular immobilizer for 4-6 weeks.
Operative treatment of posterior strernoclavicular dislocation should be undertaken when the dislocation is not reducible because most adult patients cannot tolerate posterior displacement of the clavicle into the mediastinum.
Loop of fascia lata, suture, internal fixation across the joint, subclavius tendon, osteotomy of the medial clavicle, and resection of the medial end of the clavicle have been described as treatment.