Severity (sprain, subluxation, dislocation)

Injuries can be classified by the degree of disruption at the time of injury. Sprains and subluxations are more common than dislocations. Injury to the SCJ has been historically classified by the Allman grading system. A grade I injury is a mild sprain, with partial ligamentous and capsular disruption. All ligaments are intact, and the joint is stable. In grade II injury, the capsule, intra-articular disc, and SC ligaments are injured but the costoclavicular ligaments likely remain intact, resulting in subluxation of the SC joint. Grade III injuries are considered dislocations of the SCJ, with complete disruption of the joint capsule, SC, and costoclavicular ligaments, and dislocation in an anterior or posterior direction.

Direction (anterior or posterior)

Given the relative rarity of SCJ dislocation, it is difficult to determine the exact incidence of anterior dislocation relative to posterior. However, most reports have demonstrated that anterior dislocations are 2 to 10 times more common than posterior. This is thought to be due to the robust posterior ligamentous support of the SCJ. ^, The common mechanism for an anterior dislocation is a force directed to the shoulder in a posterolateral direction, causing the shoulder to roll backward, the clavicle to lever on the underlying first rib, and the medial clavicle to dislocate anteriorly ( Fig. 26.1 ). Anterior subluxation and dislocation can also occur as a result of nontraumatic conditions such as ligamentous laxity, collagen disorders, and aplasia of the medial clavicle.

Mechanisms that produce anterior or posterior dislocation of the sternoclavicular joint. (A) If the patient is lying on the ground and a compression force is applied to the posterolateral aspect of the shoulder, the medial end of the clavicle will be displaced posteriorly. (B) When the lateral compression force is directed from the anterior position, the medial end of the clavicle is dislocated posteriorly.

(From Bucholz RW, Heckman JD, eds. Rockwood and Green’s Fractures in Adults . 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2001:1247.)

Posterior dislocations are rare. However, they are more often described in the literature due to their association with injury to the adjacent mediastinal and vascular structures. Posterior dislocations occur as result of a posteriorly directed force to the medial clavicle or an indirect force to the shoulder in the anterolateral direction (i.e., the shoulder is compressed and rolled forward), forcing the medial clavicle posteriorly (see Fig. 26.1 ; Box 26.1 ). Complications are more frequent with posterior SCJ dislocations. This is due to the proximity of the medial end of the clavicle and the mediastinal structures immediately behind the SCJ (see Chapter 25 ).

Chronicity (acute, chronic, recurrent)

Posterior SCJ injury has been reported to be missed in nearly 25% of patients on initial presentation and requires a high index of suspicion. Therefore subacute or chronic presentation is not uncommon for these injuries. Delayed diagnosis impacts treatment options, as success of closed reduction after 48 hours is significantly decreased. ^{, ,}

Age of patient (skeletally immature versus mature)

Consideration of the patient’s age is extremely important when evaluating traumatic SCJ injuries. In the skeletally immature patient, differentiation between a true dislocation and a Salter-Harris fracture of the medial clavicular physis is critical. Medial clavicle physeal injury is the skeletally immature equivalent to an adult SCJ injury. The medial clavicle epiphysis begins to ossify around age 18 to 20 years and is the last physis to close, at 20 to 25 years. This makes the medial clavicular physis the weakest point in children and skeletally immature patients ( Fig. 26.2 ). Due to this ossification process, skeletally immature patients generally do not present with true SCJ dislocations but rather displaced physeal fractures. Medial clavicle physeal injury is relatively uncommon, with only a few case reports or small case series in the literature. However, when SCJ injury is suspected in an adolescent patient, treating physicians and surgeons should have a high index of suspicion and perform the appropriate diagnostic investigations. In a recent meta-analysis, in adolescent patients undergoing open reduction for retrosternal injury, 69% had a physeal fracture whereas only 23% had a true dislocation. In the senior author’s (B.R.W.) experience, posterior SCJ subluxation and dislocation injuries in young patients (younger than 20 to 25 years) are virtually always physeal fracture injuries rather than true joint dislocations. By comparison, anterior SCJ subluxation and dislocation injuries in young patients are generally true SCJ dislocation and not physeal fractures.

Magnetic resonance image of the sternoclavicular joints. The epiphysis on the medial aspect of both clavicles is clearly visible.

(From Bucholz RW, Heckman JD, eds. Rockwood and Green’s Fractures in Adults . 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2001:1253.)

Traumatic subluxation

In a mild sprain of the SCJ (grade I injury), patients frequently describe a “pop” at the moment of contact, followed by anterior chest pain and swelling in the SCJ region. Patients with a moderate sprain or subluxation (grade II injury) describe marked pain with any movement of the arm, along with swelling. Patients may describe recurrent subluxation, where the clavicle subluxates in and out with overhead or extension shoulder movements but reduces spontaneously. It is also not uncommon for patients to complain of crepitus at the SCJ with shoulder movements.

On examination the joint may be swollen and tender to palpation, with mild to moderate pain elicited with movement of the upper extremity. Anterior subluxation is usually obvious on examination; however, posterior subluxation may not be obvious to the examiner compared with the normal, contralateral SCJ. Shoulder abduction and/or forward elevation beyond the horizontal plane often reproduces symptoms in the region of the SCJ. With anterior subluxation there may be dynamic prominence at the medial end of the clavicle, fixed subluxation, or crepitus with shoulder range of motion, whereas posterior injuries are generally more static.

Anterior dislocation

Patients often complain of a painful lump adjacent to the sternum. On examination, the affected shoulder may appear medialized, with the prominent medial end of the clavicle visibly and palpably anterior to the sternum ( Fig. 26.3 ). In severe injuries, the clavicle may actually be sitting dislocated on the anterior surface of the sternum. The clavicle may be either fixed or mobile. Patients often hold the affected extremity in adduction to prevent glenohumeral or scapulothoracic motion. There is unlikely to be injury to other thoracic structures. If the patient is younger than 25 years, physeal injury should be considered, although physeal fracture is more common in posterior injuries rather than anterior.

Clinical views demonstrating anterior dislocation of the right sternoclavicular joint.

Posterior dislocation

In cases of posterior dislocations, patients may present with an indentation at the SCJ compared with the unaffected side. The medial clavicle is displaced posteriorly and is generally less prominent compared with the unaffected side, but this is often very difficult to appreciate due to swelling. In a meta-analysis of posterior SCJ injuries, 47% of patients had other symptoms in addition to pain, swelling, and decreased motion. Due to the close proximity of the joint with major vessels and other major mediastinal structures (esophagus, trachea, and lungs) and the brachial plexus, patients can exhibit a myriad of symptoms, including venous congestion of the corresponding upper extremity, cough, stridor, hoarseness, breathing difficulties/shortness of breath, difficulty swallowing or choking sensation, and upper extremity paresthesias and/or weakness. In a systematic review of traumatic posterior SCJ dislocations in the adult population, 57 of 88 cases (65%) for which associated injuries were reported had clinical signs and symptoms and/or radiographic evidence of compression or injury of one or more mediastinal structures ( Box 26.2 ). These symptoms may also vary depending on the position of the patient, with lying supine or lateral being more problematic. If any of these symptoms are present, urgent reduction is necessary. The clinician must maintain a high index of suspicion and obtain the appropriate imaging to confirm the diagnosis.

Radiographs

Serendipity view.

Rockwood first described an oblique view of the SCJ, called the serendipity view, in 1975. The serendipity view is obtained by positioning the patient supine on the table with the radiographic beam centered directly on the sternum and angled 40 degrees cephalad ( Fig. 26.4 ). Normally, this view allows the comparison of the injured and uninjured clavicles in the same horizontal plane and can help determine superior or inferior displacement of the clavicle.

(A) Positioning of the patient to obtain a “serendipity view” of the sternoclavicular joints (SCJs). The x-ray tube is tilted 40 degrees from the vertical position and aimed directly at the manubrium. (B) Interpretation of the serendipity view. 1, In the normal scenario, both clavicles appear on the same imaginary line drawn horizontally across the film. 2, Anterior dislocation of SCJ. The medial half of the right clavicle is projected above the imaginary line drawn through the level of the normal left clavicle. 3, Posterior dislocation of the SCJ. The medial half of the right clavicle is displaced below the imaginary line drawn through the normal left clavicle. (C) Clinical example of a posterior dislocation of the left SCJ as seen on a 40-degree cephalic tilt radiograph in a 12-year-old boy. The left clavicle is displaced inferiorly to a line drawn through the normal right clavicle. (D) After closed reduction, the medial ends of both clavicles are in the same horizontal position. The buckles are a part of the figure-of-eight clavicular harness that is used to hold the shoulders back after reduction.

(A–B, From Court-Brown CM, Heckman JD, McQueen MM, et al. Rockwood and Green’s Fractures in Adults . 8th ed. Philadelphia: Lippincott Williams & Wilkins; 2015:1616. C–D, From Rockwood CA, Green DP, eds. Fractures . 2nd ed. Philadelphia: JB Lippincott;1984.)

Heinig view.

The Heinig view is a lateral view obtained when the patient is placed in a supine position. The cassette is placed adjacent the patient’s opposite shoulder and centered on the manubrium. The radiographic beam is placed approximately 30 inches from the involved SCJ and angled in the coronal plane, parallel to the longitudinal axis of the opposite clavicle, providing a profile of the affected SCJ. The Heinig view allows for the SCJ to be observed without the underlying vertebral bodies distorting the view ( Fig. 26.5 ).

(A) Positioning of the patient for radiographic evaluation of the sternoclavicular joint, as described by Heinig. (B) Heinig view demonstrating a normal relationship between the medial end of the clavicle (C) and the manubrium (M) .

(From Bucholz RW, Heckman JD, eds. Rockwood and Green’s Fractures in Adults . 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2001:1250.)

Hobbs view.

The Hobbs view is an oblique view, obtained with the patient seated and flexed over a table. The cassette is placed on the table, against the patient’s lower anterior rib cage ( Fig. 26.6 ). The patient leans forward so that the base of his or her neck is almost parallel to the table. Their elbows straddle the cassette and support the head and neck. The beam is directed through the cervical spine, producing a 90-degree cephalocaudal view.

Positioning of the patient for radiographic evaluation of the sternoclavicular joint, as recommended by Hobbs.

(Modified from Hobbs DW. The sternoclavicular joint: a new axial radiographic view. Radiology. 1968;90:801–802.)

Computed tomography scan

Given the difficulties obtaining and interpreting plain radiographs of the SCJ, axial CT is the best modality to completely evaluate the SCJ ( Fig. 26.7 ). When a posterior dislocation occurs, CT angiography should be performed if any injury to the underlying vessels is suspected or present . CT angiography should also be considered for any chronic or late presentations of posterior SCJ injury . Determining whether a posterior SCJ injury is a pure dislocation or a posterior physeal fracture is still difficult even with a CT scan, given that the medial epiphysis is primarily cartilaginous in nature ( Fig. 26.8 ). Close evaluation of the CT scan, keeping the age of the patient in mind, is important, and comparison with the noninjured (i.e., contralateral) SCJ is equally important. Following closed reduction, some authors advocate routine, repeat CT scans to confirm alignment/reduction of the joint.

Axial computed tomography scan demonstrating anterior sternoclavicular joint dislocation. Note the medial aspect of the clavicle is anterior to the manubrium.

Axial computed tomography scan demonstrating posterior medial clavicle physeal injury.

Abnormalities of the SCJ are not unusual following evaluation with a CT scan. Findings such as sclerosis, osteophytes, erosion, cysts, or joint space narrowing are commonly identified on CT scans of the SCJ in asymptomatic individuals; a combination of such findings has been identified in 50% to 90% of patients older than 60 years. In another study by Tuscano et al., approximately 10% of asymptomatic individuals demonstrated substantial asymmetry in SCJs. Therefore caution should be exercised when interpreting CT scan findings that may be interpreted as pathologic; clinical correlation is always warranted.

Magnetic resonance imaging

MRI can be used to evaluate joint alignment while also assessing the integrity of the costoclavicular ligaments, capsule and capsular ligaments, and associated vascular structures posterior to the SCJ. MRI also eliminates the risk of radiation exposure associated with CT. Compared with CT, MRI is superior in the evaluation of the bone marrow, hyaline articular cartilage, intra-articular disc, joint effusions, and the surrounding soft tissue structures. When interpreting MRI of the SCJ, sagittal images are ideal to assess the costoclavicular ligaments and attachments of the intra-articular disc. In children and young adults, MRI can be used to distinguish between SCJ dislocation and physeal injury (see Fig. 26.2 ).

Ultrasound

Ultrasound is increasingly used to provide a dynamic view of the SCJ and its associated structures. Ultrasound has demonstrated to be more accurate than radiographs to diagnose SC dislocations. In an emergency setting, ultrasound can also be used for rapid diagnosis and confirmation of joint reduction compared to radiographs, although it is user dependent and lacks the more easily interpreted detail of CT scans. There is also increasing utilization of ultrasound in the setting of athletic event coverage, where portable ultrasound units can be used on the sidelines or in an athletic training room.

Sprain/subluxation

Grade I and II SCJ sprains and subluxations should be managed nonoperatively. Patients generally respond well to conservative treatment with a short period of immobilization in a sling, ice, physical therapy, and pain control. For a grade I injury, the patient is protected with immobilization of the extremity for 1 to 3 weeks in conjunction with gradual return to activities of daily living, using physical therapy as needed. During this period, patients should avoid contact sport/activity, with a gradual return to activity after 4 to 6 weeks when there is a pain-free range of motion and return of strength. In patients with a grade II subluxation injury, a reduction of the SCJ should be attempted followed by immobilization in a sling for 4 to 6 weeks to allow the soft tissue stabilizers to heal. Physical therapy can be done after 3 to 4 weeks, focusing on shoulder range of motion and gradual strengthening. Return to activities can occur at 6 to 8 weeks. Patients should be counseled about the possibility of persistent bony prominence or asymmetry at the SCJ, although generally this is well tolerated.

Anterior sternoclavicular joint dislocation

Standard treatment for most acute anterior dislocations is nonoperative management with closed reduction. Nonoperative treatment is generally preferred because anterior dislocations have traditionally been considered to have little long-term functional impact, although this remains controversial. Initial timely closed reduction is recommended for all acute presentations of anterior dislocations because they are inherently unstable injuries. This is especially true in cases of dramatic dislocation where the clavicle is translated and perched on the sternum. In a systematic review of 241 cases, Glass et al. found that acute anterior dislocations treated initially by closed reduction achieved better functional outcomes than those treated only by open reduction. Closed reduction should be performed with the patient under sedation or general anesthesia, after confirmation of the injury using CT. The patient is placed supine and a towel roll or sandbag is placed between the scapulae. The arm is placed in 90 degrees of abduction, and traction is applied to the arm while a posterior force is applied to the medial clavicle. Following reduction, the arm should be placed in a sling for 6 weeks to reduce the risk of redislocation.

Patients with anterior SCJ dislocation should be educated of the high risk of recurrent instability with nonoperative treatment. Recurrent dislocation rates after closed reduction range between 21% and 100%. Despite high rates of redislocation, patients may continue to do well with conservative treatment, with 70% of those treated nonoperatively achieving good or excellent results (see Fig. 26.3 ). Operative treatment is generally not indicated for acute dislocation and is often reserved for patients who do not respond to nonoperative treatment. Surgical intervention should be considered for irreducible dislocations or cases where there is dramatic gross dislocation and displacement. In cases of gross anterior instability or chronic symptomatic anterior SCJ instability, surgical stabilization surgery can be performed.

Posterior sternoclavicular joint dislocation

Posterior (i.e., retrosternal) SCJ dislocations can be life-threatening injuries and thus are considered true orthopedic emergencies ( Fig. 26.9 ). As a general rule, when a posterior dislocation of the SCJ is suspected, the physician must examine the patient very carefully to rule out concomitant injury to structures posterior to the joint (see Box 26.2 ). Prior reports described a 25% to 30% incidence of injury to structures in the superior mediastinum following posterior SCJ dislocation ^, ; however, a more recent systematic review has demonstrated injuries in up to 65% of cases. When vascular injuries are suspected, CT angiogram should be performed ( Fig. 26.10 ). Acute posterior dislocation without mediastinal injury should be managed with closed reduction under general anesthesia, converting to open reduction and stabilization as necessary. ^, A commonly described reduction technique for posterior SCJ dislocation is the abduction traction method. Because reduction may cause damage to or relieve tamponade of great vessels, closed reduction should be attempted only under general anesthesia in a controlled environment. One exception to this is if the patient has evidence of airway or vascular compromise, which warrants emergent reduction. When possible, a vascular or cardiothoracic surgeon should be on standby to address thoracic injury secondary to the dislocation ( Fig. 26.11 ).

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