Posterior = Emergency | Airway Compromise | Mediastinal Structures at Risk
ROCKWOOD CLASSIFICATION
Critical Must-Knows
- Posterior dislocation is an EMERGENCY - can compress trachea, esophagus, great vessels
- SC joint is strongest joint in body - ligaments stronger than bone (physeal injury more common in under 25)
- Serendipity view (40 degree cephalic tilt) best plain film for diagnosis
- CT with contrast is gold standard - assess vascular compression
- Most dislocations are treated conservatively - recurrence well tolerated
Clinical Pearls
- "Posterior dislocation: Dysphagia, dyspnea, venous congestion in arm/neck
- "Under 25 years - likely physeal injury (SH I/II), not true dislocation
- "Do NOT reduce posterior dislocation without thoracic surgery backup
- "Figure-of-8 reconstruction with hamstring/fascia lata for chronic instability
Critical SC Joint Exam Points
Posterior = Emergency
Posterior dislocation compresses mediastinum. Signs: dysphagia, dyspnea, venous engorgement, diminished pulses. Requires EMERGENT reduction. Have thoracic surgery on standby.
Physeal Injury
SC joint physis closes at age 25 - the last physis to close in the body. In patients under 25, most "dislocations" are actually Salter-Harris fractures through the medial clavicular physis.
Serendipity View
40 degree cephalic tilt X-ray. Anterior dislocation: affected clavicle projects ABOVE opposite side. Posterior: projects BELOW. CT is definitive but serendipity view is exam favorite.
Conservative Treatment
Most SC dislocations managed conservatively. Anterior: sling 6 weeks. Even with residual subluxation, function is usually excellent. Surgery reserved for persistent symptomatic instability.
Quick Decision Guide
| Injury | Findings | Urgency | Treatment |
|---|---|---|---|
| Type I Sprain | Joint tender, stable | Non-urgent | Sling, ice, NSAIDs |
| Anterior dislocation | Clavicle prominent anteriorly | Non-urgent | Closed reduction (optional), sling 6 weeks |
| Posterior (stable patient) | Clavicle depressed, venous distension | Urgent | CT angiogram, closed reduction in OR, thoracic standby |
| Posterior (compromised) | Stridor, hypoxia, arm ischemia | EMERGENCY | Immediate reduction, airway management, thoracic surgery |
| Chronic instability | Recurrent subluxation, pain with activity | Elective | Figure-of-8 reconstruction with graft |
ABCDSC Joint Dislocation Direction
| A | Anterior Most common (25:1), clavicle prominent anteriorly |
| B | Below On serendipity view, POSTERIOR projects BELOW |
| C | Compress Posterior compresses mediastinal structures |
| D | Dangerous Posterior is dangerous - requires emergency reduction |
| A | Anterior Most common (25:1), clavicle prominent anteriorly | C | Compress Posterior compresses mediastinal structures |
| B | Below On serendipity view, POSTERIOR projects BELOW | D | Dangerous Posterior is dangerous - requires emergency reduction |
Hook:Anterior is common and cosmetic. Posterior is Perilous - watch for Problems!
STAVEPosterior SC Complications
| S | Subclavian vessels Compression or laceration |
| T | Trachea Airway compression - stridor |
| A | Artery (carotid/innominate) Vascular compromise |
| V | Vein (jugular) Venous engorgement in neck/arm |
| E | Esophagus Dysphagia |
| S | Subclavian vessels Compression or laceration | V | Vein (jugular) Venous engorgement in neck/arm |
| T | Trachea Airway compression - stridor | E | Esophagus Dysphagia |
| A | Artery (carotid/innominate) Vascular compromise |
Hook:Posterior dislocation can STAVE in the mediastinum - structures are compressed!
CICASC Joint Ligaments
| C | Costoclavicular PRIMARY stabilizer - runs from 1st rib to clavicle |
| I | Interclavicular Connects both clavicles across sternum |
| C | Capsular Anterior (strongest) and posterior capsule |
| A | Articular disc Intra-articular disc acts as shock absorber |
| C | Costoclavicular PRIMARY stabilizer - runs from 1st rib to clavicle | C | Capsular Anterior (strongest) and posterior capsule |
| I | Interclavicular Connects both clavicles across sternum | A | Articular disc Intra-articular disc acts as shock absorber |
Hook:CICA stabilizes the SC joint - Costoclavicular is king!
BUMPReduction Technique
| B | Bump Place bump between scapulae to extend shoulders |
| U | Under GA General anesthesia for muscle relaxation |
| M | Manual traction Longitudinal traction on abducted arm |
| P | Pull with towel clip If closed fails, use sterile towel clip to pull clavicle anteriorly |
| B | Bump Place bump between scapulae to extend shoulders | M | Manual traction Longitudinal traction on abducted arm |
| U | Under GA General anesthesia for muscle relaxation | P | Pull with towel clip If closed fails, use sterile towel clip to pull clavicle anteriorly |
Hook:BUMP the shoulders back and pull the clavicle forward!
Overview and Epidemiology
Incidence and Demographics:
- 3% of all shoulder girdle injuries
- Peak incidence: young adults (15-25 years) - sports, MVA
- Second peak: elderly (falls)
- Male predominance (2:1)
- Anterior dislocations 25 times more common than posterior
Mechanism of Injury:
Anterior Dislocation
- Direct blow to anteromedial clavicle (rare)
- Indirect force with lateral shoulder compression and arm forward
- Medial clavicle displaces anteriorly (lifts up and forward)
Posterior Dislocation
- Direct blow to anterolateral clavicle
- Lateral shoulder compression with arm back and down
- Medial clavicle displaces posteriorly into mediastinum
- High-energy mechanism (MVA, rugby tackle)
Clinical Pearl
Age determines pathology: In patients under 25, the medial clavicular physis (last to close at age 22-25) is weaker than ligaments - expect physeal fracture (Salter-Harris I or II) rather than true dislocation.
Anatomy and Biomechanics
Bony Anatomy:
- SC joint is the only true articulation between upper limb and axial skeleton
- Saddle-type synovial joint (incongruous surfaces)
- Medial clavicular epiphysis is the LAST physis to close (age 22-25)
- Intra-articular disc (fibrocartilage) divides joint and acts as shock absorber
Key Stabilizers:
SC Joint Stabilizers
| Structure | Function | Clinical Significance |
|---|---|---|
| Costoclavicular ligament | PRIMARY stabilizer - limits elevation, anterior/posterior translation | Short and very strong - origin of physis injury concept |
| Anterior capsular ligament | Strongest capsular component - resists posterior displacement | Must be disrupted for posterior dislocation |
| Posterior capsular ligament | Weaker - resists anterior displacement | Disrupted in anterior dislocation |
| Interclavicular ligament | Connects medial clavicles across sternum | Limits excessive clavicular depression |
| Articular disc | Intra-articular shock absorber | Can tear with subluxation |
Posterior Mediastinal Relations:
Danger Zone
The following critical structures lie only 1-2cm behind the SC joint:
- Trachea (directly posterior)
- Esophagus
- Subclavian artery and vein
- Carotid artery
- Internal jugular vein
- Innominate (brachiocephalic) artery and vein
- Brachial plexus
- Lung apex
Posterior dislocation can compress, lacerate, or thrombose any of these structures, making this a surgical emergency.
Biomechanics:
- The clavicle acts as a strut - transmits forces from upper limb to axial skeleton
- SC joint permits 35 degrees elevation, 35 degrees anterior/posterior movement, 50 degrees rotation
- True dislocation requires high energy to overcome very strong ligaments
Classification Systems
Most commonly used - based on direction and severity:
| Type | Description | Pathology | Treatment |
|---|---|---|---|
| I | Sprain | Ligaments intact, microscopic tears | Sling, ice, conservative |
| II | Subluxation | Capsule torn, costoclavicular intact | Sling 4-6 weeks |
| III | Anterior dislocation | Complete ligament rupture, anterior displacement | Usually conservative |
| IV | Posterior dislocation | Complete ligament rupture, posterior displacement | Urgent reduction required |
Clinical Pearl
Types I-III are generally managed conservatively with good outcomes. Type IV (posterior) is the only true emergency requiring urgent intervention.
Clinical Assessment
History:
- High-energy mechanism (MVA, sports collision, fall onto shoulder)
- Direct blow vs indirect (lateral shoulder compression)
- Arm position at time of injury
- Symptoms suggesting vascular/airway compromise (dyspnea, dysphagia, arm swelling)
Physical Examination:
Anterior Dislocation
- Medial clavicle prominence (palpable anteriorly)
- Pain with arm movement, especially cross-body
- Swelling at SC joint
- Full shoulder ROM typically preserved
- Cosmetic deformity is main concern
Posterior Dislocation
- Medial clavicle less prominent or hollow (depressed posteriorly)
- Venous congestion in neck or ipsilateral arm
- Dysphagia (esophageal compression)
- Dyspnea, stridor (tracheal compression)
- Hoarseness (recurrent laryngeal nerve)
- Diminished upper limb pulses (subclavian compression)
- Brachial plexus symptoms (rare)
Red Flags for Posterior Dislocation
Examine every SC joint injury for:
- Stridor or respiratory distress
- Dysphagia or odynophagia
- Venous engorgement (neck, face, ipsilateral arm)
- Diminished or absent radial pulse
- Neurological deficit (brachial plexus)
- Supraclavicular hematoma
If any present - treat as posterior dislocation until proven otherwise!
Special Tests:
- Adson test: May assess subclavian artery compression
- Pulse comparison: Compare radial pulses bilaterally
- Venous distension: Look at jugular veins and arm veins
Differential Diagnosis:
Differential Diagnosis of Medial Clavicle / SC Joint Pain or Swelling
| Condition | Distinguishing Features | Key Discriminator |
|---|---|---|
| Medial clavicle physeal fracture (Salter-Harris) | Skeletally immature patient, mechanism as for dislocation | CT/MRI shows physeal separation with metaphysis displaced; epiphysis stays reduced to manubrium |
| Medial clavicle shaft fracture | Bony tenderness lateral to joint line, crepitus | Fracture line on CT distinct from joint; far more common than SCJD |
| SC joint osteoarthritis | Older patient, gradual onset, no acute trauma | Osteophytes and joint-space loss on CT; symmetrical, activity-related ache |
| Septic SC arthritis | Fever, warmth, raised inflammatory markers, IV drug use or immunocompromise | Joint aspirate and MRI; may extend to mediastinal abscess |
| Sternoclavicular hyperostosis / SAPHO | Painful bony swelling, palmoplantar pustulosis, bilateral | Sclerosis and hyperostosis on CT; bone scan 'bullhead' sign |
| Friedrich disease (osteonecrosis of medial clavicle) | Young patient, atraumatic localised swelling | Fragmentation/sclerosis of sternal epiphysis, self-limiting |
| Mediastinal mass / lymphadenopathy | Non-mechanical swelling, systemic symptoms | Cross-sectional imaging; not related to joint or trauma |
Investigations
Imaging Modalities
| Modality | Findings | Indication |
|---|---|---|
| Standard X-rays (AP) | Often inconclusive - structures overlap | Initial screening only |
| Serendipity view (40 degree cephalic) | Anterior: clavicle UP; Posterior: clavicle DOWN | Classic exam view - good for direction |
| CT scan | Gold standard for fracture/dislocation assessment | All suspected dislocations |
| CT angiography | Vascular injury assessment | All posterior dislocations |
| MRI | Soft tissue, physeal injury in young patients | Subacute/chronic cases, physeal injury |
Clinical Pearl
Serendipity view technique: Patient supine, X-ray beam angled 40 degrees cephalad centered on sternum. Compare both SC joints on same film. Anterior dislocation: affected clavicle projects ABOVE the normal side. Posterior: projects BELOW. This is a classic exam question!
CT Findings:
- Definitive for direction of displacement
- Identifies associated fractures
- With contrast - assesses vascular compression/injury
CT Angiography
All posterior SC dislocations require CT angiography to assess for vascular compression or injury. Even after successful reduction, delayed vascular complications can occur.
Management Algorithm
Conservative Management:
Treatment Protocol
- Ice, sling for comfort
- NSAIDs for pain and inflammation
- Avoid aggravating activities
- Protected range of motion
- Wean from sling as pain allows
- Progressive ROM exercises
- Gentle strengthening
- Avoid contact sports/heavy lifting
- Full ROM should be achieved
- Sport-specific rehabilitation
- Gradual return to full activity
Prognosis: Excellent - near 100% return to full function
Surgical Technique
Indications:
- Chronic symptomatic anterior or posterior instability
- Failed conservative management
- Recurrent dislocation affecting function
Contraindications:
- Active infection
- SC joint arthritis (consider resection instead)
Surgical Steps:
- Positioning and Approach - Supine with bump under shoulders, transverse skin incision over SC joint, protect supraclavicular nerves, expose SC joint and medial clavicle
- Tunnel Preparation - Create 5-6mm tunnel through medial clavicle (anterior to posterior), create 5-6mm tunnel through manubrium or 1st rib, protect mediastinal structures with retraction and finger guard
- Graft Passage - Pass doubled graft through clavicular tunnel, cross graft in figure-of-8 pattern, pass through sternal/rib tunnel, return to clavicular tunnel
- Tensioning and Fixation - Reduce SC joint anatomically, tension graft with arm in neutral position, secure graft with interference screw or suture over bone bridge, confirm stability with stress
This technique provides stable reconstruction without metal hardware.
Complications
Complications by Injury Type and Treatment
| Complication | Anterior Dislocation | Posterior Dislocation |
|---|---|---|
| Vascular injury | Rare | Common - subclavian/innominate compression or laceration |
| Airway compromise | No | Yes - tracheal compression can be fatal |
| Dysphagia | No | Yes - esophageal compression |
| Mediastinitis | No | Risk with open reduction |
| Chronic instability | Common (usually cosmetic) | Rare if adequately reduced |
| Post-traumatic arthritis | 5-10% | 5-10% |
| Hardware migration | If metal used - can be fatal | If metal used - can be fatal |
Hardware Migration - Fatal Complication
Multiple case reports document fatal migration of pins, screws, and plates from the SC joint into:
- Heart (cardiac tamponade)
- Aorta (hemorrhage)
- Pulmonary vessels
- Subclavian vessels
Migration can occur months to years after surgery. Metal hardware is absolutely contraindicated at the SC joint.
Complication Prevention:
- Use only soft tissue reconstruction
- CT angiogram for all posterior dislocations
- Thoracic surgery standby for reduction
- Careful tunnel placement during reconstruction
Management of Complications:
- Vascular injury: Immediate thoracic/vascular surgery
- Chronic instability: Figure-of-8 reconstruction
- Arthritis: Medial clavicle resection (rare)
Postoperative Care
After Closed Reduction:
- Figure-of-8 brace or sling for 6 weeks
- NSAIDs for pain
- Ice to reduce swelling
- Serial X-rays to confirm maintained reduction
- Progressive ROM after immobilization
After Figure-of-8 Reconstruction:
Rehabilitation Protocol
- Sling immobilization
- Elbow, wrist, hand ROM maintained
- Pendulum exercises at 2 weeks
- No lifting, pushing, or pulling
- Wean from sling
- Active-assisted shoulder ROM
- Gentle isometric strengthening
- No resistance exercises
- Progressive resistance exercises
- Full ROM should be achieved
- Return to light activities
- Sport-specific training
- Gradual return to contact (if applicable)
- Functional testing before clearance
Outcomes and Prognosis
Natural History:
- Most SC injuries have excellent outcomes with conservative treatment
- Even with residual deformity, function is typically normal
- Posterior dislocations require intervention but outcomes good if promptly treated
Outcome by Injury Type
| Injury Type | Treatment | Good/Excellent Outcome | Return to Full Activity |
|---|---|---|---|
| Type I-II (Sprain) | Conservative | 95-100% | 4-6 weeks |
| Anterior dislocation | Conservative | 85-95% | 6-12 weeks |
| Posterior dislocation | Closed reduction | 80-90% | 6-12 weeks |
| Chronic instability | Figure-of-8 reconstruction | 75-85% | 4-6 months |
Prognostic Factors:
- Time to treatment (especially posterior)
- Age (younger patients do better)
- Associated injuries
- Compliance with rehabilitation
Evidence Base
Medial Clavicular Physeal Closure Age (defining anatomical reference)
- Known-age skeletal study of 605 males and 254 females aged 11-40 years; staged epiphyseal union of the medial clavicle (and anterior iliac crest)
- The medial clavicular epiphysis is among the last to unite, with partial-to-complete union spanning the late teens into the mid-twenties
- Broader age ranges for each union stage than earlier studies; male and female ranges similar or differing by only 1-2 years
- Underpins the clinical teaching that the medial clavicular physis is the last in the body to fuse
Closed Reduction of Traumatic Posterior SC Dislocation (largest single-centre series)
- Twenty-one patients with traumatic posterior SC injury; all underwent a trial of closed reduction, definitive in 8 (38%)
- Closed reduction was significantly more likely to succeed when performed within 10 days of injury
- The remaining 13 patients had open reduction and SC reconstruction; 18 of 21 overall rated good or excellent on the UCLA scale
- Successful early closed reduction obviated the risks of surgery; failed reductions did well with costoclavicular ligament reconstruction
Epidemiology of Medial Clavicle and SC Joint Injuries (nationwide data)
- Nationwide German registry analysis (ICD-10) identified 14,264 medial clavicle injuries between 2012 and 2014
- SC joint dislocation accounted for only 0.6% of clavicle-related shoulder-girdle injuries (medial clavicle fracture 11.6%) - confirming these are genuinely rare
- Bimodal age distribution with peaks around 20 and 50 years, with overall male predominance
- Females showed proportionally more injuries beyond 70 years; no significant sex difference under 16 years
Natural History and Indications - Systematic Review and Meta-analysis
- Meta-analysis of 92 acute (under 3 weeks) SC dislocations in patients 16 years and older addressing untreated outcome and reduction indications
- Anterior dislocations frequently do well managed non-operatively even when reduction is not maintained
- For posterior dislocations the evidence supports attempting closed reduction acutely, with open treatment when closed reduction fails
- The literature did not demonstrate that a cardiothoracic surgeon must be physically present, although availability remains widely recommended given catastrophic potential complications
Biomechanics of SC Joint Reconstruction (defining graft-construct study)
- Cadaveric biomechanical comparison (36 specimens) of intramedullary ligament, subclavius tendon, and figure-of-eight semitendinosus reconstructions
- Figure-of-eight semitendinosus graft through clavicular and manubrial tunnels was significantly stiffer than the other two constructs in both directions
- Peak load to failure for the semitendinosus figure-of-eight was approximately 230 N anteriorly and 241 N posteriorly, roughly three times the alternatives
- Provided the biomechanical rationale for figure-of-eight tendon-graft reconstruction now used clinically
Fatal Hardware Migration from the SC Joint (sentinel case + literature review)
- Spontaneous migration of a broken Kirschner pin from the right SC joint into the anterior mediastinum, perforating the pericardium and main pulmonary artery and causing cardiac tamponade
- Literature review emphasised the high risk of migration when pins or wires are used about the shoulder girdle, sometimes life-threatening
- Recommends mandatory removal of all metal once united, especially if broken or with local bone resorption
- Highlights the medicolegal consequences of neglected follow-up of such implants
Surgical Management of Posterior Dislocation - Systematic Review
- PRISMA systematic review of 40 studies (108 cases) of traumatic posterior SC dislocation managed surgically
- Favourable outcomes across all five stabilisation categories; overall complication rate 16% including 4 cases of recurrent instability
- Tendon-graft ligament reconstruction had the lowest recurrent instability and complication rates
- Open reduction and internal fixation required a second operation for implant removal in 80% of cases
Viva Scenarios
Clinical Decision Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Scenario 1: Posterior SC Dislocation - Emergency
"A 28-year-old male presents to the emergency department after a motorcycle accident. He complains of difficulty swallowing and shortness of breath. You note venous engorgement in his right neck and arm. The right medial clavicle appears less prominent than the left."
Thank you. This clinical picture is highly concerning for a posterior sternoclavicular dislocation, which is a surgical emergency.
Immediate assessment: I would perform an ATLS primary survey focusing on airway given the dyspnea. If the patient is stable, I would assess radial pulses bilaterally to evaluate for subclavian compression.
Diagnosis: The triad of dysphagia (esophageal compression), dyspnea (tracheal compression), and venous engorgement (venous obstruction) with a less prominent medial clavicle strongly suggests posterior SC dislocation.
Investigations: If hemodynamically stable, I would obtain an urgent CT angiogram of the chest to confirm the diagnosis and assess for vascular injury. A chest X-ray and ECG should be done while awaiting CT.
Management: This requires urgent closed reduction in the operating room. I would alert the thoracic surgery team for standby, arrange blood products, and prepare for general anesthesia. The reduction technique involves placing a bump between the scapulae to extend the shoulders, applying longitudinal traction with the arm abducted 90 degrees. If unsuccessful, I would use the towel clip technique to grasp the medial clavicle percutaneously and apply anterior traction.
Post-reduction: CT to confirm reduction, figure-of-8 brace for 6 weeks, and close monitoring for delayed vascular complications.
Scenario 2: Anterior SC Dislocation
"A 22-year-old rugby player presents with a prominent lump over his right sternoclavicular joint following a tackle. He has full range of motion of the shoulder but pain with overhead activities. Plain X-rays are inconclusive. What is your assessment and management?"
Thank you. This presentation is consistent with an anterior sternoclavicular joint injury, most likely a Type III anterior dislocation or subluxation in the Rockwood classification.
Assessment: I would first examine for any signs of posterior dislocation (dysphagia, dyspnea, venous engorgement, diminished pulses) to rule out the more dangerous alternative. Given his age (22), I would also consider that this may represent a Salter-Harris physeal injury rather than a true dislocation, as the medial clavicular physis doesn't close until age 25.
Investigations: Serendipity view (40-degree cephalic tilt) would help confirm anterior displacement. If there's any doubt, CT scan is definitive and would also show physeal injury patterns.
Management: For anterior SC dislocation, I would recommend conservative treatment. Closed reduction can be attempted but often does not stay reduced - this is acceptable. I would treat with a sling for 6 weeks, ice, and NSAIDs. I would counsel him that residual prominence is cosmetic only and function is typically excellent.
Return to sport: He can return to non-contact training at 4 weeks and full rugby at 6-8 weeks once pain-free and with full strength.
Scenario 3: Chronic SC Instability
"A 35-year-old female office worker presents with chronic pain at her right SC joint. She had an anterior dislocation 2 years ago treated conservatively. Now she has a prominent medial clavicle that subluxes with arm elevation and causes pain affecting her work. She requests surgical treatment."
Thank you. This patient has symptomatic chronic anterior SC joint instability that has failed conservative management and is affecting her function.
Assessment: I would confirm the instability is the source of symptoms by examining for provocative maneuvers that reproduce her pain and subluxation. I would also assess for signs of arthritis which may require a different approach.
Investigations: CT scan to assess joint morphology, any arthritic changes, and to plan surgery. MRI if there's concern about soft tissue pathology.
Non-operative optimization: Before surgery, I would ensure she has tried activity modification, physiotherapy focusing on scapular stability and posture, and possibly a local anesthetic/corticosteroid injection for diagnostic and therapeutic purposes.
Surgical indication: If she has failed 6+ months of conservative treatment with persistent symptomatic instability affecting her work, she is a reasonable surgical candidate.
Surgical technique: I would perform a figure-of-8 reconstruction using autograft (semitendinosus) or allograft. This involves creating tunnels through the medial clavicle and first rib/manubrium, passing the graft in a figure-of-8 pattern, and tensioning to restore stability. I would use only soft tissue - NO METAL HARDWARE due to the well-documented risk of migration into the mediastinum.
Post-operative: Sling for 6 weeks, progressive ROM, return to full activity at 4-6 months.
MCQ Practice Points
Anatomy Question
Q: What is the last epiphyseal plate to close in the human body?
A: The medial clavicular physis closes at age 22-25 years. This is clinically important because in patients under 25, SC joint injuries often represent Salter-Harris physeal fractures rather than true ligamentous dislocations, with better healing potential.
Imaging Question
Q: On a serendipity view, how does an anterior SC dislocation appear compared to the contralateral normal side?
A: The affected medial clavicle projects ABOVE the normal side in anterior dislocation. In posterior dislocation, it projects BELOW. The serendipity view is obtained with a 40-degree cephalic tilt X-ray beam centered on the sternum.
Emergency Question
Q: A patient with a posterior SC dislocation presents with stridor and dysphagia. What mediastinal structures are being compressed?
A: Trachea (causing stridor) and esophagus (causing dysphagia). Other structures at risk include the subclavian vessels, innominate artery/vein, carotid artery, internal jugular vein, and brachial plexus. This constitutes a surgical emergency.
Treatment Question
Q: What is the primary concern if metal hardware (plates/screws) is used for SC joint fixation?
A: Migration into the mediastinum. Hardware can migrate into the heart, great vessels, or lungs, causing fatal complications including cardiac tamponade and hemorrhage. Only soft tissue reconstruction (figure-of-8 with tendon graft) should be used for SC joint stabilization.
Ligament Question
Q: Which ligament is the primary stabilizer of the SC joint?
A: The costoclavicular ligament is the primary stabilizer. It runs from the first rib/costal cartilage to the inferior medial clavicle and limits elevation, anterior translation, and posterior translation of the clavicle.
Classification Question
Q: In the Rockwood classification of SC joint injuries, which type requires emergent treatment?
A: Type IV (posterior dislocation) requires urgent/emergent reduction due to risk of mediastinal structure compression. Types I-III (sprains and anterior dislocation) are generally managed conservatively.
Guidelines, Registries & Global Practice
Global Epidemiology:
Epidemiology (PubMed-sourced)
| Parameter | Figure | Source |
|---|---|---|
| Share of all traumatic joint injuries | Less than 3% | Groh & Wirth, JAAOS 2011 (PMID 21205762) |
| SC dislocation as share of clavicle-related shoulder-girdle injury | 0.6% | Bakir et al, Eur J Trauma Emerg Surg 2020 (PMID 31960070) |
| Anterior : posterior direction | Posterior far less common than anterior | Groh & Wirth, JAAOS 2011 |
| Age distribution | Bimodal peaks at approximately 20 and 50 years, male predominance | Bakir et al 2020 |
| Skeletally immature equivalent | Most 'dislocations' are medial physeal injuries | Webb & Suchey 1985; Groh & Wirth 2011 |
Guidance Across Major Bodies:
There is no dedicated AAOS, NICE or BOAST guideline specific to SC joint dislocation; this is a rare injury where practice is driven by case series, systematic reviews and trauma-system principles rather than formal society guidelines. The consensus positions below are drawn from the indexed evidence base.
Convergent International Practice Positions
| Question | Prevailing Position | Evidence Level / Source |
|---|---|---|
| Posterior dislocation urgency | Treat as an emergency; attempt prompt closed reduction, ideally within 10 days | Level IV - Groh et al, JSES 2011 (PMID 20579908) |
| Cardiothoracic cover for posterior reduction | Strongly recommended to be available; evidence does not mandate physical presence | Level IV meta-analysis - Sernandez & Riehl 2019 (PMID 30844956) |
| Anterior dislocation | Largely non-operative; accept residual prominence | Level IV - Sernandez & Riehl 2019 |
| Surgical construct of choice | Soft-tissue (tendon-graft) reconstruction over metal fixation | Level IV/V - Spencer & Kuhn 2004 (PMID 14711951); Kendal et al 2018 (PMID 30399119) |
| Pins / K-wires across the joint | Contraindicated - risk of fatal migration | Level V - Janssens de Varebeke 1993 (PMID 8140842) |
Registry and Practice Variation:
- No national joint registry (NJR, AJRR, AOANJRR, SHAR) captures SC joint dislocation as a tracked procedure, reflecting its rarity and the absence of an implanted prosthesis; the best population-level data come from national administrative datasets such as the German big-data analysis above.
- Practice variation is driven chiefly by access to cross-sectional imaging and cardiothoracic surgery rather than by regional guideline differences: in well-resourced settings CT angiography and on-site thoracic cover are standard before reducing a posterior dislocation, whereas in limited-resource settings prompt closed reduction may proceed with whatever surgical backup is available, accepting higher risk.
- The single global constant across all settings is the absolute avoidance of trans-articular metalwork.
Medicolegal Considerations
Key documentation requirements:
- Complete neurovascular examination before and after any intervention (document pulses, sensation, motor function)
- Imaging confirming direction of dislocation before reduction
- Documented thoracic surgery consultation for posterior dislocations
- Informed consent discussing hardware migration risk if any fixation planned
- CT post-reduction to confirm anatomic position
Common litigation issues:
- Delayed diagnosis of posterior dislocation leading to vascular injury
- Vascular injury during reduction without surgical backup
- Hardware migration causing cardiac/vascular injury
- Inadequate documentation of neurovascular status
STERNOCLAVICULAR JOINT INJURIES
Clinical summary
Key Statistics
- •3% of all shoulder girdle injuries
- •Anterior : Posterior ratio = 25:1
- •Medial clavicular physis closes at 22-25 years (LAST physis)
- •Under 25 = likely physeal injury, not true dislocation
Rockwood Classification
- •Type I: Sprain - ligaments intact - conservative
- •Type II: Subluxation - capsule torn - conservative
- •Type III: Anterior dislocation - usually conservative
- •Type IV: Posterior dislocation = EMERGENCY
Posterior Dislocation Signs (STAVE)
- •Subclavian vessel compression
- •Trachea compression (stridor/dyspnea)
- •Artery (carotid) compression
- •Vein (jugular) engorgement
- •Esophagus compression (dysphagia)
Management Principles
- •Anterior: Conservative - sling 6 weeks, accept prominence
- •Posterior: URGENT reduction - thoracic surgery standby
- •Chronic: Figure-of-8 reconstruction with tendon graft
- •NEVER use metal hardware - migration into mediastinum
Key Imaging
- •Serendipity view: 40 degree cephalic tilt
- •Anterior = clavicle projects ABOVE normal
- •Posterior = clavicle projects BELOW normal
- •CT/CTA mandatory for posterior (assess vascular)
Must Know for Exam
- •Posterior SC dislocation is a surgical emergency
- •Thoracic surgery backup mandatory for reduction
- •No metal hardware at SC joint (fatal migration)
- •Costoclavicular ligament is primary stabilizer
- •Last physis to close = medial clavicle (22-25y)