George S. Athwal
Disorders of the sternoclavicular joint are uncommon in comparison to other shoulder girdle problems. The sternoclavicular joint may be affected by traumatic conditions, such as dislocation and fracture, or atraumatic conditions such as arthritis and infection. Diseases like sternocostoclavicular hyperostosis, osteitis condensans, Friedrich disease and spontaneous joint instability also affect the sternoclavicular joint but are rare. Posterior joint dislocations, although uncommon, are of particular concern owing to their high risk of serious complications including respiratory compromise, vascular compromise, hoarseness, brachial plexus compression, and death. A thorough understanding of these disorders and the associated clinical and radiograph findings will allow accurate diagnosis and appropriate treatment.
Pathogenesis
Etiology
Dislocation of the sternoclavicular (SC) joint requires a remarkable amount of force, which may be applied directly or indirectly. A direct force dislocation occurs when a sufficiently strong posterior directed force is applied to the anterior aspect of the medial clavicle, and as a result the medial clavicle dislocates posteriorly toward the mediastinal structures. An indirect force dislocation, the most common mechanism of injury, may result in anterior or posterior sternoclavicular joint instability. An anterior SC joint dislocation occurs when an anterolateral compressive force is applied to the shoulder creating an external rotatory torque on the clavicle with resultant anterior displacement of the medial clavicle. A posterior dislocation results when the opposite occurs, a posterolateral compressive force results in an internal rotatory torque on the clavicle with associated posterior dislocation of the medial clavicle. The two most frequent causes of SC joint subluxation or dislocation are motor vehicle collisions (40%) and contact sports (27%), such as rugby or football. Other traumatic causes of injury are falls, crush injuries and heavy lifting.
Degenerative arthritis is the most common condition affecting the sternoclavicular joint. Its exact cause is unknown; however, it is thought to be multifactorial in origin (e.g., hereditary, trauma, aging, and joint laxity). Sternoclavicular arthritis has also been associated with spinal accessory nerve palsy secondary to radical neck surgery. The nerve palsy results in shoulder ptosis, which increases stresses transmitted across the SC joint resulting in early degenerative changes. A history of manual labor is also a risk factor for the development of symptomatic osteoarthritis. Rheumatoid arthritis involvement of the SC joint is variably reported in the literature.
Infections of the sternoclavicular joint are usually bacterial and are commonly associated with intravenous drug use and immunocompromised states such as acquired immunodeficiency syndrome (AIDS) or chemotherapy. Other predisposing conditions for SC joint sepsis include rheumatoid arthritis, alcoholism, bacteremia, and chronic diseases.
Epidemiology
Sternoclavicular joint injuries are rare and represent <1% of all joint dislocations. With respect to the shoulder girdle, they represent only 3% of injuries—compared with 85% for glenohumeral dislocations and 12% for acromioclavicular joint injuries. Anterior SC joint dislocations are much more common than posterior dislocations, with an anterior-to-posterior ratio of 20:1.
The incidence of sternoclavicular degenerative arthritis is likely underreported as it is very often misdiagnosed and mistreated. The frequency of SC degenerative arthritis increases with age, and studies have found degenerative changes in 90% to 100% of patients over the age of 70 years. Postmenopausal women are more susceptible than either men or premenopausal women to osteoarthritis; however, the etiology is unknown. Rheumatoid arthritis (RA) involvement of the SC joint has been reported in as many as 30% of patients, and changes were usually present within 1 year of diagnosis.
Septic arthritis of the sternoclavicular joint appears to have a higher incidence in intravenous drug abusers. Common causative organisms are Staphylococcus aureus and Streptococcus species. Immunocompromised patients
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have other causative organisms, such as Pseudomonas aeruginosa, Neisseria gonorrhoeae, and Candida albicans.
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TABLE 31-1 Classification of Sternoclavicular Joint Instability |
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Pathophysiology
The sternoclavicular joint is a diarthrodial, saddle-type joint which is the only true synovial articulation between the upper extremity and the axial skeleton. The epiphysis of the medial clavicle is the last to appear and the last to close at 23 to 25 years of age. The SC joint has limited intrinsic bony stability as less than half of the medial clavicle articulates with the superolateral manubrium; therefore, stability is provided by the robust capsular ligaments and the strong costoclavicular and interclavicular ligaments. An intra-articular disc ligament exists that divides the joint into two separate spaces; it functions to reduce incongruities between the articular surfaces and as a restraint to medial displacement of the clavicle.
Ligament sectioning studies have found increased anterior and posterior joint translation (41% and 106%, respectively) with release of the posterior joint capsule. Anterior capsular release was found to increase only anterior translation, and sectioning of the costoclavicular and the interclavicular ligaments resulted in insignificant joint translation. Therefore, it is thought that the posterior joint capsule is the most important restraint to anterior and posterior sternoclavicular joint translations.
Anatomically, the sternoclavicular joint is located anterior to vital superior mediastinal structures. These structures include the innominate artery and vein, the subclavian artery and vein, the recurrent laryngeal nerve, the phrenic nerve, the vagus nerve, the esophagus, and the trachea. Posterior dislocation of the medial clavicle may compromise any of these structures with potential life-threatening consequences. These vital structures are also placed at risk during operative management of sternoclavicular disorders, such as arthrotomy for infection and open reduction of dislocations.
Classification
Sternoclavicular joint disorders are relatively uncommon and span a wide spectrum of orthopedic diseases (trauma, arthritis and infection). Therefore, a universal classification scheme does not exist.
Sternoclavicular joint instability may be classified according to etiology, chronicity, direction, and degree of instability (Table 31-1). A formal classification system for degenerative arthritis of the sternoclavicular does not exist; therefore, standard principles may be applied. Degenerative changes in the SC joint initiate at the inferior part of the medial clavicular head, which articulates with the manubrium. Mild osteoarthritis has radiographic changes consisting of minimal joint space narrowing and small osteophytes. Moderate osteoarthritis has further joint space narrowing, subchondral sclerosis, and larger peripheral osteophytes while severe arthritis has complete cartilage loss.
Diagnosis
Physical Examination and History
Clinical Features
Instability.
Sternoclavicular joint injury is most frequently the result of a motor vehicle collision or a sports-related trauma. A detailed history will allow determination of the mechanism of injury as patients may describe a direct blow to the anterior chest or medial compression to the shoulder girdle with resultant indirect SC joint injury. Patients may complain of pain, tenderness or deformity around the SC joint. Symptoms of hoarseness, shortness of breath, difficultly swallowing, or choking should be elicited as they may indicate posterior dislocation of the medial clavicle with concomitant mediastinal compression.
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Patients with acute SC joint dislocation will present with swelling, tenderness, and severe pain that is exacerbated with arm movement. The differentiation between anterior and posterior dislocation can usually be made on physical examination; however, in cases of severe swelling, accurate diagnosis may be difficult. With an anterior dislocation, the medial clavicle is prominent and can be palpated anterior to the manubrium. In patients with a posterior dislocation, the prominent medial clavicle is absent and the manubrium is more easily palpated. Patients with posterior dislocations may also exhibit signs of damage to the pulmonary and vascular systems, such as stridor, venous congestion, or hemodynamic instability.
Sternoclavicular joint subluxation without dislocation may be subtle and consist of only mild pain, tenderness, and swelling. Joint instability may be tested by translating the medial clavicle joint in the anteroposterior direction and comparing with the contralateral side. Patients with atraumatic or spontaneous sternoclavicular joint instability can usually demonstrate with minimal discomfort subluxation or dislocation with arm elevation that spontaneously reduces when the arm is brought down.
Arthritis.
Patients with degenerative arthritis report activity-related pain and swelling at the sternoclavicular joint. Symptoms are exacerbated by palpation of the joint and active shoulder elevation. The medial clavicle may be prominent owing to osteophytes and may also be in fixed subluxation. Patients with rheumatoid arthritis usually report similar findings of pain, swelling, and joint crepitus; however, isolated joint involvement of the SC joint in RA is rare.
Joint Sepsis.
Septic arthritis of the sternoclavicular joint is uncommon and is usually associated with immunocompromised states (human immunodeficiency virus [HIV]), rheumatoid arthritis, renal dialysis, or intravenous drug abuse. The hallmark features are pain, swelling, tenderness, and erythema over the SC joint. Constitutional symptoms, such as fever, chills, and night sweats, are common.
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Figure 31-1 Three-dimensional CT reconstruction of a traumatic right posterior sternoclavicular joint dislocation. |
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Figure 31-2 Axial CT image of a posterior sternoclavicular joint dislocation with associated compression of the mediastinal structures, notably the trachea. |
Radiographic Features
Radiography.
Standard radiographic projections are difficult to interpret for sternoclavicular joint injuries because of overlapping anatomic structures. Several special projections have been described to aid in the diagnosis of SC joint pathology, including the serendipity and Hobb views. The serendipity view is performed with the patient supine and the radiography tube angled at 40 degrees cephalad, centered on the manubrium; this image allows a relative axial view of the joint. The Hobb view approximates a 90-degree lateral view of the SC joint and is performed with the patient leaning over the radiography table so that the flexed neck is almost parallel to the table. Radiographs should be assessed for joint congruity (instability), signs of arthritis (OA), and erosions with joint destruction (neoplasm, sepsis).
Computed Tomography.
Computed tomography (CT) provides a simple and accurate method of assessing the SC joint and has been reported as being the best imaging modality. It is important to image both sides for comparison of the pathologic to the normal contralateral side. CT scans can also be reformatted into three-dimensional images to allow accurate representation of the SC joint (Fig. 31-1). When interpreting studies with posterior SC joint dislocations, a particular benefit is the ability to assess mediastinal structures and their potential compromise (Fig. 31-2). In patients with such findings, CT with angiography is indicated.
Magnetic Resonance Imaging.
Magnetic resonance imaging (MRI) provides a more detailed and specific identification of SC joint soft tissues and mediastinal structures. Coronal MRI images are ideal for evaluation of the SC joint
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articular surfaces, the intra-articular disc, and the interclavicular and costoclavicular ligaments. The axial views are useful in assessing the anterior and posterior sternoclavicular ligaments, joint congruity, and the relationship between vital mediastinal structures and the SC joint.
Diagnostic Workup Algorithm
The SC joint is subject to the same disease processes that occur in other joints (instability, osteoarthritis, rheumatoid arthritis, infection, fracture). A detailed history outlining symptom onset, systemic complaints, family history, and social history will lead to a provisional diagnosis. Physical examination with a focus on joint translation, swelling, fluctuance, warmth, and signs of pulmonary-vascular compromise will further hone the diagnosis. Imaging with radiographs and CT will be confirmatory and assist with treatment planning.
Treatment
Surgical Indications/Contraindications
Instability
Anterior Sternoclavicular Joint Dislocation.
Acute traumatic anterior SC joint dislocations are generally treated with closed reduction under sedation or general anesthesia. Anterior dislocations are generally easily reduced; however, they tend to remain unstable and there is a high redislocation rate. Because of the high complication rate of surgery and the low rate of persistent symptoms or functional deficit with nonoperative treatment, it is recommended that redislocated SC joints be treated conservatively.
The technique of closed reduction involves the patient being supine with a moderate-sized bolster placed between the shoulders. The arm is abducted to 90 degrees with gentle traction followed by a posterior-directed force applied to the medial clavicle. If a stable reduction ensues, the patient may be immobilized in a figure-of-eight bandage, a Velpeau bandage, a clavicle strap harness, or a bulky pressure pad taped over the medial clavicle for 6 weeks. If the SC joint redislocates, the patient may be placed in a shoulder sling for comfort until symptoms subside.
Operative stabilization of traumatic anterior SC joint instability should be considered only in patients who have failed nonoperative treatment. Patients may complain of pain, deformity, and crepitus. Various procedures have been described to stabilize the medial clavicle or reconstruct the SC joint. The author's preferred technique is reconstruction of the anterior and posterior SC joint capsule and sternoclavicular ligaments with tendon graft woven through the manubrium and medial clavicle (Fig. 31-3). The patient is positioned in a 40-degree upright beach-chair position. The surgical approach involves an oblique 6- to 8-cm incision centered over the medial clavicle extending over the manubrium. The platysma muscle is divided, and the medial clavicle and SC joint are exposed. Drill tunnels (3 to 4 mm in diameter) are created in the medial clavicle, and the manubrium followed by passage of the tendon graft. The joint is reduced, and the tendon graft is secured. This is followed by suture repair of the costoclavicular ligaments and remaining soft tissues to augment the reconstruction. Other surgical options include the Burrow procedure (subclavius tendon tenodesis to medial clavicle), sternal head of sternocleidomastoid muscle transfer, costoclavicular ligament reconstruction with tendon graft, and distal clavicle resection with soft tissue stabilization.
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Figure 31-3 Tendon-weave reconstruction of the anterior and posterior sternoclavicular joint capsule and sternoclavicular ligaments. The tendon graft is passed through drill tunnels created in the medial clavicle and manubrium. |
Posterior Sternoclavicular Joint Dislocation.
Patients with a posterior SC joint dislocation should undergo a thorough history and physical examination assessing for associated mediastinal injuries. Mediastinal injuries, if present, should be completely investigated and the appropriate referrals made to vascular, cardiothoracic, or general surgery.
Acute traumatic posterior SC joint injuries that present within 7 to 10 days should be treated with an attempted closed reduction. Once reduced, unlike anterior dislocations, posterior dislocations tend to remain stable. Closed reduction should be conducted in the operating room with appropriate anesthesia and with vascular or thoracic surgery available. The most commonly described reduction maneuver is the abduction-traction technique, in which the patient is positioned supine with a medium-sized bolster placed between the shoulders. The arm is abducted to 90 degrees with traction; as the arm is gently extended, the medial clavicle is levered forward with a reduction occurring usually with an audible snap. If the reduction is unsuccessful, the medial clavicle may be manually manipulated to bring it forward, and if this is also unsuccessful, a sterile towel clip may be used to grasp the clavicle to pull it forward. Resistant posterior SC joint dislocations have also been reduced by another maneuver termed the adduction-traction technique. This technique involves gentle traction to the adducted arm with a posterior-directed force applied to both shoulders, which levels the medial clavicle over the first rib and into its normal position.
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Indications for surgical treatment of posterior SC joint dislocations include an unsuccessful or unstable closed reduction, chronic posterior instability, or chronic posterior dislocations. Patients with chronic posterior SC joint dislocations without initial symptoms of mediastinal compromise have experienced significant late complications such as vascular compromise, thoracic outlet syndrome, and erosion of the medial clavicle into vital mediastinal structures (arteries and veins). The operative technique of open reduction and stabilization is identical as for anterior SC joint dislocations, and the reader is referred to the previous section.
Arthritis
Patients with symptomatic arthritis of the sternoclavicular joint are best managed with nonoperative treatment, such as anti-inflammatory medications, local steroid injections, and activity modification. Patients with rheumatoid arthritis should also be managed medically in conjunction with a rheumatologist.
Indications for the surgical management of SC joint arthritis include persistent pain and functional limitation despite maximized nonoperative treatment. Operative treatment involves excision of the medial end of the clavicle with preservation of the posterior sternoclavicular and costoclavicular ligaments. On average, 8 to 10 mm of medial clavicle is excised; if too much is excised or if damage to the stabilizing ligaments occurs, clavicular instability may occur.
Infection
Sternoclavicular joint sepsis is managed medically with organism-specific parenteral antibiotics, along with surgical irrigation and debridement. In subacute and chronic cases with delayed diagnosis, abscess formation with bone destruction may necessitate partial SC joint resection and first rib debridement. Untreated or partially treated infections may progress to extrapleural or intrathoracic abscess with potentially life-threatening complications. In severe cases with extensive debridement, patients may require transposition of the ipsilateral pectoralis major muscle to obliterate residual space and to reconstruct the chest wall.
Complications
Complications from anterior SC joint dislocations are usually mild. Patients may complain of a noncosmetic bump at the medial end of the clavicle or symptoms consistent with late degenerative arthritis.
Nonoperative management of posterior SC joint dislocations has been associated with a wide variety of complications owing to the proximity of the joint to the mediastinal structures. Documented complications include pneumothorax, respiratory distress, venous congestions, laceration of the superior vena cava, compression of the subclavian artery, brachial plexopathy, esophageal rupture, tracheoesophageal fistula, and hoarseness. Although the rate of complications has been documented at 25%, the reported fatality rate is low.
Complications from the operative treatment of SC joint disorders vary depending on the type of surgical procedure. Complications of medial clavicle resection usually relate to damage of the stabilizing ligaments leading to instability and pain. Most complications associated with past operative stabilization procedures for traumatic SC joint injuries related to hardware migration. Kirschner wires, Steinmann pins, and Hagie pins used to transfix the SC joint have migrated and punctured vital structures; therefore, alternative means of joint stabilization are recommended such as autograft or allograft tendon reconstruction.
Results and Outcome
Because of the uncommon nature of sternoclavicular joint disorders, there are few good outcomes studies. Studies in the literature are limited by their retrospective design, few patient numbers, and variable clinical follow-up.
In general, the literature on nonoperative management of anterior sternoclavicular joint dislocations states a 70% to 80% satisfaction rate (return to normal activities and no SC joint pain). Posterior SC joint dislocations that are successfully managed with closed reduction appear universally to do well in the literature, with minimal pain and disability, no recurrences, and minimal crepitus.
There is little information in the literature on the outcomes of surgically treated posterior SC joint dislocations. Analysis of the few studies available shows the results are highly variable and may depend on the type of operative procedure. Procedures involving resection of the medial clavicle without stabilization appear to have poor outcomes owing to residual instability. Medial clavicle resection procedures with maintenance or reconstruction of the supporting ligaments have a 70% good to excellent outcome. Outcomes with open reduction and ligament reconstruction are also variable and range from 42% to 90% good to excellent results.
The management of sternoclavicular arthritis with medial clavicle resection with preservation of the stabilizing joint structures provides a 70% to 90% good to excellent outcome at medium- to long-term follow-up. Once again, the studies available are few, retrospective, with low patient numbers, and use variable outcome measures.
Postoperative Management
Instability
The postoperative management of SC joint instability surgery involves protection of the shoulder and SC joint with a shoulder immobilizer and limited motion consisting of pendulum exercises for 6 weeks. Patients may then progress to passive range of motion, active assisted motion, and then to active range of motion. Shoulder-strengthening exercises are initiated at 3 months.
Arthritis
The postoperative management of medial clavicle resection for arthritis is similar to the postoperative management of SC joint instability surgery. The rehabilitation goals are to allow adequate healing of the sternoclavicular soft tissues to prevent late instability while allowing protected shoulder motion.
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Infection
Sternoclavicular joint arthrotomy, irrigation, and debridement should be managed in a shoulder immobilizer for comfort. Patients requiring aggressive debridement with medial clavicle excision should be managed similarly to patients with medial clavicle resections for arthritis.
Suggested Readings
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