Classification and Management
Anatomy of the Sternoclavicular Joint
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The sternoclavicular joint is a saddle-shaped synovial joint.
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It is formed by the articulation between:
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Medial end of the clavicle
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Manubrium of the sternum
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First costal cartilage
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Stabilizing Structures
Key stabilizing structures of the sternoclavicular joint include:
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Anterior and posterior joint capsule
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Intra-articular fibrocartilaginous disk
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Interclavicular ligament
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Costoclavicular ligament
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Subclavius muscle, which provides significant dynamic stabilization
Biomechanics and Mobility
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Elevation and depression occur between the clavicle and the intra-articular disk.
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Protraction and retraction occur between the disk and the sternum.
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The joint allows:
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Approximately 35 degrees of arc of movement
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Up to 45 degrees of axial rotation
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This mobility is essential for normal upper limb function.
Critical Surrounding Structures
Important structures located posterior to the sternoclavicular joint include:
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Brachiocephalic vein
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Internal jugular vein
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Common carotid artery
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Trachea
Clinical significance
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Posterior dislocations can cause life-threatening injury to these vital mediastinal structures.
Why Anterior Dislocations Are More Common
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The posterior capsule and ligaments are thicker and stronger than the anterior capsule.
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Strong posterior stabilizing structures prevent backward displacement of the medial clavicle.
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The anterior capsule is comparatively weaker.
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Traumatic forces therefore more commonly cause anterior displacement of the clavicle.
Mechanism of Injury
Traumatic Dislocations
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Usually caused by an indirect oblique force to the shoulder.
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The lateral end of the clavicle moves backward.
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The medial end rotates forward away from the sternum.
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Joint instability occurs due to tearing of:
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Sternoclavicular ligament
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Interclavicular ligament
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Costoclavicular ligament
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Atraumatic Dislocations
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More commonly seen in patients younger than 20 years.
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May occur spontaneously or following minimal trauma.
Associated factors include:
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Generalized ligamentous laxity
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Abnormal muscle activation patterns
Key muscles involved:
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Clavicular portion of pectoralis major
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Sternocleidomastoid muscle
Clinical Presentation
Anterior Dislocation
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Localized pain over the sternoclavicular joint
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Visible and palpable prominence lateral to the sternum
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Reduced range of motion of the shoulder
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Numbness or paraesthesia in the affected upper limb
Important consideration
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In young patients, medial clavicle physeal fractures must be ruled out, as the medial clavicular physis may remain open until approximately 25 years of age.
Physical Examination
Clinical assessment should include:
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Careful inspection and palpation of the joint
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Assessment of shoulder range of motion
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Complete neurovascular examination
Posterior dislocation warning signs
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Difficulty in breathing
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Difficulty in swallowing
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Signs of vascular compromise
Diagnostic Imaging
Plain Radiography
Recommended views:
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Anteroposterior view
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Serendipity view
Radiographic findings:
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Anterior dislocation: medial clavicle appears superior compared to the opposite side
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Posterior dislocation: medial clavicle appears inferior
Computed Tomography Scan
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Considered the gold standard for evaluation.
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Essential to differentiate true dislocations from physeal fractures.
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Confirms diagnosis when plain radiographs are inconclusive.
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Allows assessment of mediastinal structures.
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Provides accurate visualization of joint alignment.
Magnetic Resonance Imaging
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Used selectively to assess ligamentous and soft tissue injury.
Classification Systems
Stanmore Classification
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Type I: Traumatic dislocation with structural damage
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Type II: Atraumatic dislocation due to laxity or degenerative changes
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Type III: Muscle patterning abnormality, commonly involving overactivity of pectoralis major
Allman Classification
Primarily used for traumatic dislocations:
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Grade I: Sprain without joint laxity
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Grade II: Sternoclavicular ligament rupture with intact costoclavicular ligament
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Grade III: Complete rupture of both sternoclavicular and costoclavicular ligaments with complete joint dissociation
Management Overview
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Management strategies are broadly divided into:
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Nonoperative treatment
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Operative treatment
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Most anterior sternoclavicular joint dislocations are initially managed conservatively.
Nonoperative Management
Indications
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Most acute anterior dislocations
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Atraumatic dislocations
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Minimally symptomatic chronic anterior dislocations
Treatment Protocol
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Immobilization using:
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Sling
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Figure-of-eight bandage
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Adequate pain control
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Immobilization period of 4 to 6 weeks
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Gradual return to activity, usually by 3 months
Closed Reduction
Indications
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Acute anterior dislocations presenting within 7 to 10 days
Technique
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Performed under sedation or general anesthesia
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Patient positioned supine with a bolster between the shoulders
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Arm placed in 90 degrees of abduction with 10 to 15 degrees of extension
Post-Reduction Immobilization
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Immobilization for 4 to 6 weeks using:
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Clavicular strap
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Figure-of-eight splint
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Sling
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Scapular protraction is maintained to improve stability.
Clinical note
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Anterior dislocations are frequently unstable even after reduction.
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Reported redislocation rates range from 21 percent to 100 percent.
Indications for Surgical Management
Surgery is considered in the following situations:
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Failure of conservative treatment
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Failed closed reduction
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Chronic or recurrent symptomatic instability
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High-demand patients, including athletes
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Poor bone quality requiring rigid fixation
Surgical Techniques
Non-Absorbable Suture Fixation
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Sutures passed through drill holes in the manubrium and clavicle.
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Configured in parallel or figure-of-eight patterns.
Advantages
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Minimally invasive
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Provides multiplanar stabilization
Suture Anchor Technique
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Non-absorbable sutures secured using implantable bone anchors.
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Creates a suture bridge construct.
Advantages
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Strong fixation
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Minimizes joint motion during healing
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Supports biological ligament healing
Tendon Autograft Reconstruction
Graft options
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Semitendinosus tendon, preferred
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Gracilis tendon as an alternative
Surgical steps
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Harvest a tendon graft measuring at least 14 centimeters
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Curved incision over the sternoclavicular joint
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Open joint capsule
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Drill tunnels in the sternum and clavicle
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Pass graft in a figure-of-eight configuration
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Repair capsule and surrounding muscles
Clinical benefits
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Excellent joint stability
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Good functional recovery
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High rates of return to sports and daily activities
Locking Plate Fixation
Indications
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Poor bone quality such as osteoporosis
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Need for rigid stabilization
Technique
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Anterosuperior curved incision over the joint
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Removal of unhealthy or damaged tissue
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Temporary reduction using a Kirschner wire
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Application of a pre-contoured plate spanning the clavicle and sternum
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Fixation using:
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Bicortical screws in the clavicle
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Unicortical screws in the sternum
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Benefit
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Durable fixation in osteoporotic bone
Hook Plate Technique
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Originally designed for acromioclavicular joint injuries.
Adaptation for sternoclavicular joint
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Hook placed behind the manubrium to act as an anchor
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Acts as a lever to reduce the medial clavicle
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Plate fixed to the clavicle with screws
Advantages
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Rigid fixation
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Allows early mobilization
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Restores joint alignment
Sternoclavicular Joint-Specific Plate
Design features
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Anatomically contoured for the sternoclavicular joint
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Plate and hook system
Technique
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Plate fixed anteriorly using bicortical screws
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Hook passed through the manubrium from posterior to anterior
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Nuts and washers may be added for additional stability
Outcomes
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Significant reduction in pain scores
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High patient satisfaction
Complications and Risks
General Surgical Risks
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Infection
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Hardware irritation or prominence
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Need for hardware removal
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Donor site morbidity in autograft procedures
Procedure-Specific Risks
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Recurrence of instability, especially after closed reduction
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Injury to mediastinal structures, particularly with posterior dislocations or hook plates
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Suture or anchor failure
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Joint stiffness
Kirschner Wire-Related Risks
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Wire migration has been reported into major structures such as the aorta, lungs, and trachea
Key Takeaways
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Management should be individualized based on patient age, symptoms, activity level, and bone quality.
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Conservative treatment is the first-line approach for most acute anterior dislocations.
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Surgical intervention is reserved for chronic instability, high-demand patients, or failed conservative care.
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Selection of surgical technique depends on functional requirements, bone quality, and surgeon expertise.
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Most patients achieve satisfactory functional outcomes with appropriate management.
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