Sternoclavicular Joint Injury: Identify, Treat & Recover
Key Takeaway
Your ultimate guide to Sternoclavicular Joint Injury: Identify, Treat & Recover starts here. A sternoclavicular joint injury involves damage to the SC joint, located where the collarbone (clavicle) meets the breastbone (sternum) at the base of the neck. This unique joint is the only true articulation between the upper extremity and the axial skeleton. Though rare, injuries can be serious, causing pain, swelling, and reduced shoulder movement, often resulting from direct impact or indirect force to the shoulder.
Introduction and Epidemiology
Sternoclavicular joint injuries represent a rare but potentially life-threatening subset of shoulder girdle trauma. Accounting for less than three percent of all fractures and dislocations about the shoulder, sternoclavicular joint pathology demands a high index of suspicion and a thorough understanding of regional anatomy. The sternoclavicular articulation is the sole true synovial joint connecting the appendicular skeleton of the upper extremity to the axial skeleton. Due to its robust ligamentous constraints, significant kinetic energy is required to disrupt this joint, making these injuries most common in high-velocity motor vehicle collisions and high-impact contact sports such as football and rugby.
Dislocations are broadly classified into anterior and posterior directions relative to the sternum. Anterior dislocations are vastly more common, outnumbering posterior dislocations by a ratio of approximately nine to one. While anterior dislocations are generally benign and primarily present cosmetic or chronic biomechanical concerns, posterior dislocations constitute a true orthopedic emergency. The posterior displacement of the medial clavicle places the critical structures of the superior mediastinum at immediate risk of compression or laceration.
The mechanism of injury is typically categorized as either direct or indirect. Direct trauma involves a force applied to the anteromedial aspect of the clavicle, driving it posteriorly into the mediastinum. This often occurs when an athlete is supine and sustains a compressive force from another player falling directly onto the chest, or during vehicular crush injuries. Indirect trauma is the more common etiology for both anterior and posterior dislocations. A lateral compressive force applied to the shoulder girdle translates medially. If the shoulder is rolled forward during impact, the medial clavicle is driven posteriorly. Conversely, if the shoulder is rolled backward, the medial clavicle is levered anteriorly.
Clinical evaluation reveals a patient who typically presents supporting the affected extremity across the trunk with the contralateral arm to offload the shoulder girdle. The patient’s head is frequently tilted toward the side of the injury to decrease tension on the sternocleidomastoid muscle and minimize stress across the joint. Patients will exhibit marked swelling, focal tenderness, and a severely restricted, painful range of shoulder motion. In cases of posterior dislocation, the clinician must maintain a high index of suspicion for signs of mediastinal compression, including dyspnea, dysphagia, dysphonia, venous engorgement of the ipsilateral upper extremity, or diminished distal pulses.
Surgical Anatomy and Biomechanics
The sternoclavicular joint is a diarthrodial joint characterized by a saddle-like configuration. The articular surface of the medial clavicle is convex vertically and concave anteroposteriorly, articulating with the reciprocal surface of the clavicular notch of the manubrium. The articular surface of the clavicle is significantly larger than that of the sternum, resulting in less than half of the medial clavicle articulating with the sternum at any given time. Both articular surfaces are covered with hyaline cartilage, but the joint itself contains a robust fibrocartilaginous intra-articular disc. Because of this architectural mismatch, the sternoclavicular joint possesses the least amount of intrinsic bony stability of any major joint in the human body.
Ligamentous Stabilizers
Joint integrity relies almost entirely on the surrounding capsuloligamentous structures. The joint capsule is thickened anteriorly and posteriorly, with the posterior capsule being significantly stronger and providing the primary resistance against both anterior and posterior translation.
The intra-articular disc ligament acts as a crucial checkrein against medial displacement of the clavicle. It originates from the chondro-sternal junction of the first rib and inserts onto the superior and posterior aspects of the medial clavicle, effectively dividing the joint into two separate synovial cavities.
The extra-articular costoclavicular ligament, also known as the rhomboid ligament, is a short, strong band that resists superior rotation and medial-lateral displacement. It consists of an anterior fasciculus, which resists superior displacement, and a posterior fasciculus, which resists anterior and posterior translation.
The interclavicular ligament spans the jugular notch, connecting the superomedial aspects of both clavicles and the superior manubrium. This structure helps to maintain shoulder poise and resists downward glide of the lateral clavicle, which would otherwise lever the medial clavicle superiorly.
Kinematics and Range of Motion
Despite its strong ligamentous bindings, the sternoclavicular joint is highly mobile, functioning as the pivot point for all shoulder girdle movements. The normal range of motion includes 35 degrees of superior elevation, 35 degrees of combined anteroposterior motion, and up to 50 degrees of rotation around the clavicle's longitudinal axis during full shoulder abduction and elevation.
Physeal Considerations
The medial clavicle physis is unique in human development; it is the last primary ossification center to appear and the last to close. Ossification typically begins between 18 and 20 years of age, and fusion with the clavicular shaft is not complete until 25 to 30 years of age. Consequently, many injuries diagnosed clinically or radiographically as sternoclavicular joint dislocations in patients under the age of 25 are, in fact, Salter-Harris type I or II physeal fractures. The strong periosteal sleeve usually remains attached to the sternum via the sternoclavicular ligaments, allowing for excellent remodeling potential in this age group.
Mediastinal Anatomy
The proximity of the sternoclavicular joint to the superior mediastinum dictates the morbidity and mortality associated with posterior dislocations. Immediately posterior to the joint lies the innominate (brachiocephalic) vein. Deeper structures include the superior vena cava, the aortic arch and its major branches (brachiocephalic trunk, left common carotid, left subclavian arteries), the trachea, the esophagus, and the vagus and phrenic nerves. Disruption of the posterior capsule and posterior displacement of the clavicle can lead to catastrophic injury to any of these structures.
Indications and Contraindications
The management of sternoclavicular joint injuries is dictated by the direction of displacement, the chronicity of the injury, the presence of mediastinal compression, and the age of the patient. Anterior dislocations are overwhelmingly managed non-operatively, as closed reduction is rarely stable and the functional deficit of an unreduced anterior dislocation is minimal. Operative intervention for anterior instability is reserved for highly symptomatic chronic cases or impending skin necrosis.
Posterior dislocations demand urgent reduction. Closed reduction is the first line of treatment and should be performed in the operating room under general anesthesia, with a thoracic surgeon immediately available. If closed reduction fails, or if the patient presents with hemodynamic instability, vascular compromise, or severe respiratory distress, emergent open reduction is indicated.
Management Decision Matrix
| Clinical Scenario | Primary Intervention | Secondary Intervention |
|---|---|---|
| Acute Anterior Dislocation | Non-operative (Sling for comfort, early ROM) | Operative reconstruction if skin tenting or severe chronic pain develops |
| Acute Posterior Dislocation | Closed reduction in OR under general anesthesia | Open reduction and stabilization if closed reduction fails or is unstable |
| Posterior Dislocation with Mediastinal Compromise | Emergent Open Reduction | Cardiothoracic surgical exploration and repair of injured structures |
| Medial Clavicle Physeal Fracture (<25 years old) | Closed reduction (often remodels well even if imperfect) | Open reduction if severe posterior displacement cannot be reduced closed |
| Chronic Symptomatic Instability | Physical therapy, activity modification | Figure-of-8 autograft/allograft reconstruction |
Contraindications to operative intervention include asymptomatic chronic anterior dislocations, medically unstable patients unfit for anesthesia (unless the instability is secondary to mediastinal compression from the dislocation), and active local infection.
Pre Operative Planning and Patient Positioning
Thorough preoperative planning is paramount, particularly for posterior dislocations, given the potential for catastrophic intraoperative complications.
Imaging Modalities
Standard anteroposterior radiographs of the chest and clavicle are often difficult to interpret due to overlapping osseous structures. The "Serendipity view" is a specialized radiograph taken with the patient supine and the x-ray beam angled 40 degrees cephalad, centered on the manubrium. On this view, an anteriorly dislocated medial clavicle will appear superior to the horizontal axis of the normal clavicle, while a posteriorly dislocated clavicle will appear inferior to it.
Despite the utility of specialized plain films, a computed tomography (CT) scan is the gold standard for evaluating sternoclavicular joint pathology. CT provides definitive multiplanar visualization of the joint articulation, allows for differentiation between true dislocations and medial physeal fractures, and accurately delineates the relationship of the medial clavicle to the mediastinal structures. If there is any clinical suspicion of vascular compromise, a CT angiogram (CTA) of the chest and neck should be obtained to rule out laceration or pseudoaneurysm of the brachiocephalic vessels.
Interdisciplinary Coordination
For any posterior sternoclavicular joint dislocation, a cardiothoracic or vascular surgeon must be consulted and ideally present or immediately available during the reduction maneuver. The operating room should be prepped for a potential median sternotomy in the event of iatrogenic vascular injury during reduction.
Patient Positioning
The patient is placed in the supine position on a radiolucent operating table. A bump (such as a rolled towel or sandbag) is placed vertically between the scapulae. This allows the shoulders to fall posteriorly, which aids in the reduction of a posterior dislocation by retracting the lateral clavicle posteriorly and levering the medial clavicle anteriorly. The entire chest, neck, and bilateral upper extremities should be prepped and draped into the sterile field to allow for unhindered manipulation of the shoulder girdle and access for sternotomy if required.
Detailed Surgical Approach and Technique
Closed Reduction Technique
Closed reduction of a posterior dislocation is attempted first. With the patient under general anesthesia and paralyzed to eliminate muscle spasm, the surgeon stands at the head of the bed. Two primary techniques are utilized:
1. Abduction Traction: The affected arm is abducted to 90 degrees and extended. Axial traction is applied to the arm while an assistant applies counter-traction to the torso. The surgeon may manually grasp the medial clavicle and lift it anteriorly.
2. Adduction Traction: If abduction fails, the arm is adducted against the torso, and downward traction is applied. This utilizes the first rib as a fulcrum to lever the medial clavicle anteriorly.
If manual manipulation is insufficient, a sterile towel clip can be percutaneously applied to the medial clavicle (taking care to avoid deep penetration into the mediastinum) to apply direct anterior traction. A distinct "clunk" typically indicates successful reduction. Once reduced, posterior dislocations are generally stable due to the intact anterior capsule acting as a hinge.
Open Reduction and Reconstruction
If closed reduction fails, or in the setting of chronic symptomatic instability, open reduction and ligamentous reconstruction are indicated. The gold standard for reconstruction is the figure-of-8 technique utilizing a tendon autograft (semitendinosus or gracilis) or allograft.
Incision and Dissection
A transverse or curvilinear incision is made centered over the sternoclavicular joint, extending roughly 4 centimeters laterally along the clavicle and 3 centimeters medially over the manubrium. Subcutaneous tissues are divided, and the platysma is incised in line with the skin incision. Careful dissection is required to identify and protect the medial branches of the supraclavicular nerve.
The periosteum of the medial clavicle and the anterior capsule of the sternoclavicular joint are incised. In acute posterior dislocations, the medial clavicle is often found lodged behind the intact anterior capsule and manubrium. Subperiosteal dissection is performed, taking extreme care on the posterior aspect of the clavicle and manubrium. A blunt curved retractor (such as a malleable or a small Crego retractor) must be placed posterior to the manubrium and clavicle to protect the underlying vascular structures during drilling.
Joint Preparation and Reduction
Interposed tissue, which frequently includes the torn intra-articular disc or remnants of the posterior capsule, is cleared from the joint space. The clavicle is manipulated using a tenaculum or towel clip to achieve anatomic reduction. In cases of chronic instability or arthritis, a limited resection of the medial clavicle (no more than 10 to 15 millimeters) may be performed to prevent abutment, though preserving the articular geometry is preferred if joint integrity is to be reconstructed.
Figure-of-8 Reconstruction
Using a 3.5 mm or 4.0 mm drill, two holes are created in the medial clavicle and two corresponding holes in the manubrium. The drill holes in the clavicle are placed approximately 10 to 15 mm lateral to the articular surface, oriented from anterior to superior and anterior to inferior. The manubrial holes are placed 10 mm medial to the articular surface.
Critical Surgical Pearl: The drill must never plunge posteriorly. The protective retractor placed behind the bone must be palpable by the drill tip, and drilling should be performed under direct visualization with a controlled, oscillating technique if possible.
The selected tendon graft is passed through the drill holes in a figure-of-8 fashion. The graft is passed from anterior to posterior through the inferior clavicular hole, then posterior to anterior through the inferior manubrial hole. It crosses over the joint anteriorly, passes anterior to posterior through the superior manubrial hole, and finally posterior to anterior through the superior clavicular hole. The graft is tensioned with the sternoclavicular joint held in anatomic reduction and sutured to itself using heavy non-absorbable sutures.
Closure
The remaining anterior capsular tissue is imbricated over the reconstruction to provide additional anterior stability. The platysma is meticulously closed to ensure a cosmetically acceptable scar, followed by standard dermal and epidermal closure.
Complications and Management
Surgical management of the sternoclavicular joint carries a unique and potentially devastating complication profile. The historical use of Kirschner wires, Steinmann pins, or other smooth metallic implants for sternoclavicular fixation is strictly contraindicated. There is a well-documented history of these implants migrating into the mediastinum, resulting in cardiac tamponade, aortic puncture, and death. Modern reconstruction relies exclusively on suture and soft-tissue graft techniques.
Complication Matrix
| Complication | Incidence | Etiology | Prevention and Salvage Strategy |
|---|---|---|---|
| Vascular Laceration | Rare but catastrophic | Posterior plunging of drill or instruments; reduction maneuver | Always use a posterior protective retractor. Immediate thoracic surgery intervention for salvage. |
| Recurrent Instability | 5% - 15% | Graft stretching, non-compliance with immobilization | Revision reconstruction with robust allograft; possible limited medial clavicle excision if symptomatic. |
| Hardware/Pin Migration | High (if used) | Cyclic loading of the shoulder girdle | Absolute contraindication. Never use pins across the SC joint. |
| Post-Traumatic Osteoarthritis | 20% - 30% | Cartilage damage at time of injury | Conservative management; late medial clavicle excision (arthroplasty) if conservative measures fail. |
| Cosmetic Deformity | Common in anterior dislocations | Prominence of the medial clavicle | Patient counseling; surgical intervention rarely indicated solely for cosmesis. |
Infection is a risk with any open procedure, particularly when utilizing allograft tissue. Superficial infections are managed with oral antibiotics, while deep space infections require urgent irrigation and debridement, potentially necessitating graft removal if the infection cannot be cleared.
Thoracic outlet syndrome or localized nerve irritation can occur if excessive scar tissue forms around the reconstruction or if the medial supraclavicular nerves are entrapped in the incision. Careful soft tissue handling and precise anatomical dissection minimize this risk.
Post Operative Rehabilitation Protocols
Successful outcomes following sternoclavicular joint reconstruction depend heavily on strict adherence to postoperative rehabilitation protocols. The reconstructed joint must be protected from the massive lever-arm forces generated by the upper extremity until the tendon graft has incorporated and soft tissue healing is complete.
Phase I: Maximum Protection (Weeks 0 to 6)
Immediately postoperatively, the patient is placed in a standard shoulder sling or a figure-of-8 harness. The primary goal during this phase is to protect the graft.
* Absolute restriction on active shoulder elevation, abduction, and extension.
* Passive range of motion is limited to 90 degrees of forward flexion and 90 degrees of abduction.
* Elbow, wrist, and hand active range of motion is encouraged to prevent distal stiffness.
* Scapular retraction exercises are initiated to maintain periscapular tone without stressing the sternoclavicular joint.
Phase II: Active-Assisted to Active ROM (Weeks 6 to 10)
At six weeks, clinical and radiographic evaluations are performed. If stable, the sling is discontinued.
* Gradual progression to full active-assisted and then active range of motion.
* Avoidance of heavy lifting or forceful pushing/pulling.
* Initiation of closed-kinetic-chain exercises for the shoulder girdle to promote dynamic stability.
* Isometric strengthening of the deltoid and rotator cuff.
Phase III: Strengthening and Return to Function (Weeks 10 to 16)
Once full, painless active range of motion is achieved, progressive resistance exercises are integrated.
* Isotonic strengthening focusing on the pectoralis major, trapezius, rhomboids, and latissimus dorsi.
* Plyometric exercises are introduced late in this phase for athletic patients.
Phase IV: Return to Play (Months 4 to 6)
Clearance for contact sports or heavy manual labor is typically granted between 4 and 6 months postoperatively, contingent upon the restoration of symmetric shoulder strength and the absence of pain or apprehension during sport-specific activities.
Summary of Key Literature and Guidelines
The academic consensus on sternoclavicular joint injuries emphasizes the critical distinction between anterior and posterior dislocations. Wirth and Rockwood's seminal work on the management of sternoclavicular joint injuries established the foundation for modern treatment algorithms, clearly delineating the non-operative mandate for the vast majority of anterior dislocations and the urgent need for reduction in posterior variants.
Biomechanical studies, notably those by Spencer et al., have validated the figure-of-8 tendon graft reconstruction as the strongest and most anatomically accurate method for restoring joint stability. Their cadaveric models demonstrated that the figure-of-8 construct utilizing a semitendinosus graft most closely replicates the native strength of the posterior capsule and costoclavicular ligaments, significantly outperforming subclavius tendon transfers and synthetic ligament augmentations.
Current orthopedic guidelines mandate the following critical tenets:
1. Imaging: A CT scan is mandatory for any suspected posterior sternoclavicular dislocation to assess mediastinal proximity and rule out physeal fracture.
2. Surgical Backup: Closed or open reduction of a posterior dislocation must never be attempted without a cardiothoracic or vascular surgeon immediately available.
3. Fixation: The use of smooth or threaded pins across the sternoclavicular joint is universally condemned due to the unacceptably high risk of lethal intrathoracic migration.
4. Physeal Awareness: In patients under 25 years of age, presumed dislocations should be treated as physeal fractures, which have excellent remodeling potential and generally favorable outcomes with closed treatment.
By adhering to these evidence-based principles, orthopedic surgeons can effectively manage this complex and potentially dangerous joint pathology, ensuring optimal functional recovery while minimizing life-threatening complications.
Clinical & Radiographic Imaging
