Other Names

• SC Joint Dislocation
• Sternoclavicular Joint Subluxation
• SC Joint Subluxation
• SCJ Dislocation
• SCJ Subluxation
• Sternoclavicular Dislocation

Pathophysiology

• Anterior
  • Typically results from lateral compressive force to the shoulder girdle
  • Results in rupture of the anterior capsule, part of the costoclavicular ligament
• Posterior
  • Typically caused by a direct force over the anteromedial aspect of the clavicle or an indirect force to the posterolateral shoulder,
  • Subsequently forcing the medial clavicle posteriorly

Causes

• Traumatic
  • Trauma most common etiology, usually MVC or collision sports (need citation)
• Atraumatic
  • Occurs with an overhead elevation of the arm
  • Subluxed cases may reduce by lowering the arm
  • Less common, seen with collagen deficiency syndromes such as Hypermobility Syndrome
  • Even less common is a congenital deformity, abnormal muscle pattern, infection or osteoarthritis

The SC joint itself receives direct supply by the medial supraclavicular nerve (C3-C4) and the nerve to the subclavius (C5-C6). It is also worth mentioning nerves are involved in the various movements at the joint.

• Elevation: accomplished by the levator scapulae, upper trapezius, rhomboid major and minor muscles

  • Innervation: dorsal scapular nerve, C5 ventral ramus, C3-C4 ventral rami

• Depression: pectoralis minor, lower trapezius, serratus anterior and inferior muscles

  • innervation: medial pectoral nerve, spinal accessory nerve, long thoracic nerve

• Protraction: pectoralis minor, serratus anterior muscles

  • Innervation: medial pectoral nerve, long thoracic nerve

• Retraction: middle trapezius, latissimus dorsi, rhomboid major and minor muscles

  • innervation: spinal accessory nerve, thoracodorsal nerve, dorsal scapular nerve

• Rotation via elevation of the glenoid cavity: upper and lower trapezius, serratus anterior and inferior muscles

  • Innervation: suprascapular nerve, axillary nerve, long thoracic nerve

• Rotation via depression of the glenoid cavity: levator scapulae, latissimus dorsi, pectoralis minor, rhomboid major and minor muscles

  • Innervation: dorsal scapular nerve, thoracodorsal nerve, medial pectoral nerve, dorsal scapular nerve

Pathoanatomy

• Sternoclavicular Joint
  • Articular of Sternum, medial Clavicle
  • Inherently unstable due to minimal osseous articulation, thus dependent on ligamentous structures for stability
• Stabilizers
  • The joint capsule and capsular ligaments (most important)
  • Costoclavicular Ligament
  • Interclavicular Ligament
  • Sternoclavicular ligaments
  • Subclavius

Associated Injuries

• Posterior dislocation
  • Primary concern: compression of mediastinum which can be life-threatening
  • Neurovascular injuries including brachial plexus
  • Tracheal injury
  • Esophageal injury
• Other orthopedic injuries
  • Acromioclavicular Joint Separation (rare)

• Atraumatic
  • Hypermobility Syndrome
  • Ehlers-Danlos Syndrome
  • Other collagen deficiency conditions
  • Osteoarthritis

Differential Diagnosis

• Fractures
  • Proximal Humerus Fracture
  • Humeral Shaft Fracture
  • Clavicle Fracture
  • Scapula Fracture
  • First Rib Fracture (traumatic or atraumatic)
• Dislocations & Seperations
  • Acromioclavicular Joint Separation
  • Glenohumeral Dislocation (Acute)
  • Sternoclavicular Joint Dislocation
  • Glenohumeral Instability (Chronic)
• Arthropathies
  • Glenohumeral Arthritis
  • Acromioclavicular Joint Arthritis
• Muscle & Tendon Injuries
  • Pectoralis Major Injuries
  • Pectoralis Minor Injuries
  • Proximal Biceps Tendon Injuries
  • Scapular Dyskinesis
• Rotator Cuff
  • Rotator Cuff Tear
  • Rotator Cuff Tendonitis
  • Calcific Tendinitis of the Rotator Cuff
  • Subcoracoid Impingement Syndrome
• Bursopathies
  • Subacromial Bursitis
  • Scapulothoracic Bursitis
• Ligament Injuries
  • Glenoid Labral Tears
• Neuropathies
  • Suprascapular Nerve Injury
  • Parsonage-Turner Syndrome
  • Quadrilateral Space Syndrome
  • Winged Scapula
• Other
  • Adhesive Capsulitis
  • Paget-Schroetter Syndrome
• Pediatrics
  • Coracoid Avulsion Fracture
  • Humeral Head Epiphysiolysis (Little League Shoulder)

Diagnosis

• History
  • Will generally report high energy collisions (i.e. sports, MVC, etc)
  • Anterior: complaint of painful lump lateral to the sternum
  • Posterior: medial clavicular pain
  • Posteriors may also report dyspnea, dysphagia, or other vascular or neurological symptoms
• Physical: Physical Exam Shoulder
  • You may observe the patient with the shoulder adducted across the chest to prevent excessive motion
  • Prominence increases with abduction, the elevation of the arm
  • Swelling, bruising may be noted
  • Reduced ROM at the shoulder
  • Critical to performing the thorough pulmonary, laryngeal, esophageal, and neurovascular examination

Radiographs

• Standard Radiographs Shoulder
• Routine chest radiographs have poor sensitivity and are notoriously challenging to identify SCJ dislocations
• Mandatory to exclude other associated injuries (pneumothorax, hemothorax, pneumomediastinum, etc)
• Serendipity View
  • Beam with 40° cephalic tilt^[3]
  • Presents the anterior dislocation as a superiorly displaced medial clavicle
  • Presents the posterior dislocation is an inferiorly displaced medial clavicle
• Heining View
  • The beam is directly perpendicular to the SCJ^[4]
  • Allows the SCJ to be visualized without underlying vertebral bodies distorting the view

CT

• Diagnostic modality of choice in suspected sternoclavicular dislocation
• Visualizes mediastinal structures
• Helps differentiate from physeal injuries
• Angiography may be indicated if vascular injury suspected

MRI

• Poorer resolution than CT
• Useful to evaluate ligamentous injuries

Ultrasound

• Case reports using point-of-care ultrasound to identify sternoclavicular dislocations^[5]

Classification

• Direction: anterior, posterior, superior, inferior
• Instability: acute, recurrent, persistent

Stanmore triangle

• Originally applied to glenohumeral instability, extrapolated to SCJ dislocation
• Type I: traumatic structural
  • Clear history of trauma
• Type II: atraumatic structural
  • No history of trauma, structural changes within the capsule
• Type III: muscle patterning, nonstructural
  • Structurally intact
  • Muscles, namely Pectoralis Major causing SCJ subluxation or dislocation

Treatment

Acute Management

• Anterior Dislocation
  • Acute anterior dislocation attempted closed reduction with procedural sedation or in the OR
  • Procedure
    • The patient is placed supine with a bolster placed between their shoulders
    • Traction is applied to the affected upper limb in 90° of abduction with neutral flexion
    • Direct pressure is applied over the medial clavicle.
  • Immobilize in Shoulder Immobilizer for 3-4 weeks
• Posterior Dislocation
  • Acute posterior dislocation attempted closed reduction with procedural sedation or in the OR
  • Rockwood Technqiue^[3]
    • A towel clip is used percutaneously to grasp the medial clavicle and pull it anteriorly
  • Abduction traction technique^[6]
    • Shoulder is abducted to 90° and traction applied
    • Extension force is then applied to the shoulder resulting in anterior translation of the medial clavicle back into joint
  • Buckerfield technique^[7]
    • Retraction of the shoulders with caudal traction on the adducted arm, while the patient is supported by an interscapular bolster

Nonoperative

• Anterior
  • Most can be managed non-surgically
  • Shoulder Sling initially
  • Physical Therapy
  • Analgesia including NSAIDs, Acetaminophen
  • Small subgroup develops persistent symptomatic instability
• Posterior
  • At the discretion of the orthopedic surgeon

Operative

• Anterior Indications
  • Acute (<2-3 weeks)
  • Failure of a non-surgical approach
  • Persistent pain
• Posterior Indications
  • Acute (<2-3 weeks)
  • Neurovascular, esophageal or tracheal injury
• Technique
  • Generally closed reduction for both anterior or posterior
  • Open reduction with thoracic surgery back up if any neurovascular, esophageal or tracheal injuries
  • Medial clavicle excision if persistent pain or chronic instability