Sternoclavicular Joint Dislocations: Comprehensive Surgical Management

Comprehensive Introduction and Patho-Epidemiology

The sternoclavicular (SC) joint represents the sole true synovial articulation between the axial skeleton and the upper extremity, serving as the foundational pivot point for all dynamic movements of the shoulder girdle. Because of its unique diarthrodial saddle configuration, it possesses minimal intrinsic osseous stability, relying almost entirely on a robust, highly specialized complex of surrounding ligaments. Traumatic dislocation of the sternoclavicular joint is a relatively rare but highly significant clinical entity, accounting for less than 3% of all shoulder girdle injuries. These dislocations typically result from high-energy indirect forces transmitted through the shoulder girdle, such as those encountered in high-speed motor vehicle collisions, equestrian accidents, and high-impact contact sports like rugby and American football.

The pathophysiology of SC joint instability is dictated by the direction of the applied force vector. Anterior dislocations, which are vastly more frequent, generally occur when an indirect force is applied to the anterolateral aspect of the shoulder with the arm abducted, rolling the shoulder backward and levering the medial clavicle anteriorly. Conversely, posterior (retrosternal) dislocations result from a direct blow to the anteromedial clavicle or an indirect force driving the posterolateral shoulder forward. While anterior dislocations generally carry a benign long-term prognosis even when left unreduced, posterior dislocations are potentially catastrophic. The posterior displacement of the medial clavicle places the critical structures of the superior mediastinum—including the trachea, esophagus, great vessels, and brachial plexus—at immediate risk of mechanical compression or devastating laceration.

Epidemiologically, these injuries predominantly affect young, active males in their second to fourth decades of life. This demographic reality introduces a critical diagnostic nuance: the medial clavicular epiphysis is the last physis in the human body to close, typically fusing between the ages of 23 and 25 years, and sometimes as late as 31 years. Consequently, what appears clinically and radiographically as a true sternoclavicular dislocation in a patient under the age of 25 is overwhelmingly a Salter-Harris type I or II fracture through the medial clavicular physis. In these pediatric and young adult variants, the robust periosteal sleeve remains intimately attached to the sternum via the intact SC ligaments, while the clavicular shaft displaces through the path of least resistance at the growth plate.

The historical management of sternoclavicular joint dislocations has evolved significantly, shifting away from perilous hardware fixation toward advanced soft-tissue reconstruction and, when appropriate, benign neglect. The management of these injuries demands a profound, three-dimensional understanding of regional anatomy, precise diagnostic imaging protocols utilizing advanced cross-sectional modalities, and meticulous surgical technique. The orthopedic surgeon must be prepared to navigate a complex anatomical landscape where the margin for error is measured in millimeters, and multidisciplinary collaboration with cardiothoracic or trauma surgery is frequently an absolute necessity.

Detailed Surgical Anatomy and Biomechanics

To master the operative and nonoperative management of the SC joint, the orthopedic surgeon must first understand its complex osteology and stabilizing soft-tissue structures. The joint is a diarthrodial saddle joint, but the articular surfaces are remarkably incongruent. Less than half of the medial aspect of the clavicle articulates with the shallow clavicular notch of the manubrium sterni and the superior aspect of the first costal cartilage. This inherent osseous mismatch means that the joint's stability is completely dependent on its capsuloligamentous envelope. The medial clavicle itself is bulbous and provides a broad surface area for the attachment of these critical structures.

Stability is conferred by a highly orchestrated complex of four primary soft-tissue structures. The capsular ligaments envelop the joint and are significantly thickened both anteriorly and posteriorly. Biomechanical studies have definitively proven that the posterior capsule is the most robust structure and represents the primary restraint to both anterior and posterior translation of the medial clavicle. The intra-articular disc, a dense fibrocartilaginous meniscus, divides the joint into two separate synovial cavities. It attaches superiorly to the posterosuperior aspect of the medial clavicle and inferiorly to the first costal cartilage, acting simultaneously as a dynamic hinge and a vital shock absorber. The interclavicular ligament spans the jugular notch, connecting the superomedial aspects of both clavicles and resisting downward displacement of the distal clavicle. Finally, the costoclavicular (rhomboid) ligament is a dense, bipartite structure connecting the inferior surface of the medial clavicle to the first rib. Its anterior and posterior fascicles cross obliquely, providing critical stability against superior displacement and axial rotation.

Whether the sternoclavicular joint subluxates or fully dislocates depends entirely on the sequential failure of these specific structures. A mild sprain may involve only the anterior capsular ligaments, while a complete dislocation requires the catastrophic rupture of the anterior and posterior capsular ligaments, the intra-articular disc, and the costoclavicular ligament. Biomechanically, the SC joint must accommodate a massive range of motion to allow normal shoulder function; it elevates up to 35 degrees, depresses 35 degrees, and rotates up to 45 degrees along its longitudinal axis during full shoulder abduction and forward elevation. Any surgical reconstruction must therefore not only restore stability but also preserve this complex, multi-planar kinematics to prevent severe functional impairment of the entire upper extremity.

The posterior aspect of the SC joint is separated from the superior mediastinum by a perilous margin of only a few millimeters, defining the "danger zone" of shoulder surgery. Structures immediately posterior include the innominate (brachiocephalic) veins, the superior vena cava, the aortic arch, the right brachiocephalic artery, the left common carotid artery, the trachea, the esophagus, and the thoracic duct. The innominate vein lies directly posterior to the SC joint, separated only by the strap muscles (sternohyoid and sternothyroid) and the posterior capsule. This unforgiving anatomical reality dictates the catastrophic potential of posterior dislocations and mandates extreme caution, meticulous subperiosteal dissection, and the mandatory use of posterior protective retractors during any operative intervention.

Exhaustive Indications and Contraindications

The decision-making algorithm for the management of sternoclavicular joint dislocations is highly nuanced, requiring the surgeon to synthesize the chronicity of the injury, the direction of displacement, the patient's physiological age, and the presence or absence of mediastinal compromise. Acute anterior dislocations are almost universally managed non-operatively. Even when closed reduction is successful, the inherent disruption of the anterior capsuloligamentous complex renders the joint highly unstable, and re-dislocation is the rule rather than the exception. Fortunately, the functional outcomes of unreduced anterior dislocations are typically excellent, with the primary patient complaint being cosmetic asymmetry rather than functional deficit.

Conversely, an acute posterior dislocation constitutes a true orthopedic emergency. The posteriorly displaced medial clavicle can produce immediate and life-threatening respiratory distress (stridor), venous congestion, arterial insufficiency, brachial plexus compression, and myocardial conduction abnormalities. Emergent closed reduction is indicated for all acute posterior dislocations. If closed reduction fails, or if the patient presents with progressive hemodynamic instability or neurovascular compromise, emergent open reduction is absolutely indicated. In cases of chronic, symptomatic anterior or posterior instability that severely limits the patient's activities of daily living or occupational duties, delayed ligamentous reconstruction or medial clavicle excision may be considered as a salvage procedure.

Contraindications to surgical intervention must be strictly observed to prevent iatrogenic morbidity and mortality. The most critical absolute contraindication in sternoclavicular joint surgery is the use of transarticular smooth pins (Steinmann pins or Kirschner wires). The literature is replete with tragic reports of fatal complications resulting from the intra-thoracic migration of intact or broken pins into the heart, pulmonary artery, innominate artery, or aorta. Fixation must rely entirely on robust suture, suture-tape augmentation, or autograft/allograft reconstruction. Relative contraindications include asymptomatic chronic dislocations, poor surgical candidates with severe medical comorbidities, and active local or systemic infection.

Pre-Operative Planning, Templating, and Patient Positioning

Thorough pre-operative planning is the cornerstone of safe and effective sternoclavicular joint surgery. Physical examination will reveal asymmetry of the medial clavicles, but clinical assessment alone is insufficient to dictate surgical intervention. Standard anteroposterior (AP) radiographs of the chest or shoulder are notoriously difficult to interpret due to the dense overlapping shadows of the ribs, sternum, and thoracic vertebrae. While the Serendipity view (an apical lordotic view centered over the sternum with the X-ray tube tilted 40 degrees cephalad) can help determine the direction of displacement, it lacks the anatomical fidelity required for surgical planning.

Computed Tomography (CT) is the absolute gold standard and is mandatory for evaluating SC joint pathology. Thin-slice axial, coronal, and sagittal reconstructions, paired with 3D volume rendering, definitively differentiate between true dislocations and medial physeal fractures. Furthermore, CT angiography (CTA) is a critical adjunct in all posterior dislocations. CTA allows the surgeon to precisely assess the proximity of the displaced medial clavicle to the great vessels, identify occult intimal tears or pseudoaneurysms, and map the exact trajectory of the innominate vein and artery. This imaging must be reviewed in conjunction with a cardiothoracic or vascular surgeon prior to any intervention.

Multidisciplinary coordination is non-negotiable. For any open reduction of a posterior dislocation, a cardiothoracic surgeon must be formally consulted and ideally present in the operating room, or immediately available on standby. The surgical team must ensure that a sternal saw, vascular clamps, and cardiopulmonary bypass capabilities are readily accessible. Furthermore, the patient must have blood products typed and crossed, and large-bore intravenous access (frequently central venous access) must be established by the anesthesia team prior to induction.

Patient positioning is designed to maximize surgical access while facilitating potential intra-operative reduction maneuvers. The patient is placed in the supine position on a radiolucent operating table. A large, firm sandbag or a vertically rolled towel is positioned vertically between the scapulae. This allows the shoulders to fall posteriorly, opening the anterior chest and frequently assisting in the leverage required to disengage a posteriorly locked medial clavicle. The surgical prep and drape must be extensive, extending from the patient's chin down to the costal margin, and laterally to encompass both deltoids and the entire affected upper extremity, allowing for free manipulation of the arm during the procedure.

Step-by-Step Surgical Approach and Fixation Technique

Surgical intervention begins with a final attempt at closed reduction under general anesthesia, particularly for posterior dislocations. The standard abduction-traction technique or the Buckerfield and Castle maneuver (utilizing the first rib as a fulcrum) is employed. If these fail, or if the surgeon is addressing chronic instability, an open approach is initiated. A 7- to 8-cm transverse or L-shaped incision is made, centered directly over the SC joint, extending laterally over the medial third of the clavicle and medially over the manubrium sterni. The subcutaneous tissues and the platysma are sharply divided to expose the superficial fascia.

Meticulous, strictly subperiosteal dissection is the most critical technical aspect of the exposure. The periosteum of the medial clavicle is incised longitudinally. Using a Freer elevator and progressively larger Cobb elevators, the periosteum is elevated. The surgeon must remain intimately on the bone, particularly along the posterior cortex. A blunt, malleable retractor or a Doyen rib raspatory is then carefully advanced posterior to the medial clavicle and manubrium. This retractor must remain in place for the duration of the procedure to serve as a physical barrier, protecting the delicate innominate vein and mediastinal structures from inadvertent plunge injuries during drilling or dissection. The joint is then sharply debrided; the torn intra-articular disc and interposed capsular remnants are excised to allow for an anatomical reduction.

Because simple capsular repair is biomechanically insufficient to maintain reduction, a formal ligamentous reconstruction is required. The gold standard is the figure-of-eight graft reconstruction, originally popularized by Kennedy, utilizing either a semitendinosus autograft or a robust allograft. Using a 3.2mm or 4.0mm drill, two holes are created in the medial clavicle (oriented superior to inferior) and two corresponding holes are drilled in the manubrium. The trajectory of these tunnels must be meticulously controlled, and the posterior cortex must be breached only against the firm resistance of the protective posterior retractor.

Once the osseous tunnels are prepared, the graft is passed through the drill holes in a figure-of-eight configuration. To enhance the biomechanical strength of the construct, modern techniques frequently augment the biological graft with heavy, non-absorbable suture tape (e.g., InternalBrace technology). The medial clavicle is anatomically reduced into the sternal notch, and the graft and suture tape are tensioned and secured. The graft is sutured to itself using heavy #2 or #5 non-absorbable sutures. Finally, the remaining anterior capsule and the robust periosteal sleeve are imbricated and repaired tightly over the reconstruction in a "pants-over-vest" fashion to provide a secondary layer of static stability and promote biological healing.

Complications, Incidence Rates, and Salvage Management

Surgical intervention at the sternoclavicular joint is fraught with risk and must be approached with profound respect for the regional anatomy. Historical reports by Worman and Leagus, Brown, and Omer suggest that the incidence of significant complications approaches 25% following sternoclavicular procedures, particularly when hardware fixation is attempted. The most catastrophic complication is iatrogenic vascular injury. Laceration of the innominate vein, superior vena cava, or aortic arch during dissection or drilling carries a massive mortality rate. Immediate packing, sternotomy, and emergent vascular repair by a cardiothoracic surgeon are required if this nightmare scenario unfolds.

Hardware-related complications dictate the absolute contraindication of transarticular pinning. The cyclical, multi-planar motion of the SC joint leads to rapid metal fatigue, wire breakage, and subsequent intra-thoracic migration. Recurrent instability is the most common non-lethal complication, occurring in 10% to 15% of soft-tissue reconstructions. This is often due to premature return to activity, failure of graft incorporation, or unrecognized disruption of the costoclavicular ligament. Superficial and deep surgical site infections are also notable risks, given the thin soft-tissue envelope over the anterior chest wall.

Thoracic outlet syndrome and brachial plexopathy can occur secondary to hypertrophic callus formation following a physeal fracture or exuberant scar tissue post-reconstruction. Furthermore, prolonged post-operative immobilization frequently leads to adhesive capsulitis of the glenohumeral joint, necessitating aggressive, delayed physical therapy. Cosmetic deformity, characterized by a prominent medial clavicle (the "Bactrian camel" sign), is almost universal in non-operatively managed anterior dislocations and can persist even after successful reconstruction.

When primary reconstruction fails, or in cases of severe, debilitating chronic instability where the joint surfaces are highly arthritic, salvage management is required. The most reliable salvage procedure is a medial clavicle excision. The critical technical pearl during this procedure is that the resection must be limited to the medial 1.5 to 2.0 centimeters of the clavicle. The surgeon must strictly preserve the costoclavicular (rhomboid) ligament. If the costoclavicular ligament is violated or excised, the entire clavicle will become unstable, leading to devastating global shoulder dysfunction. Arthrodesis of the SC joint is rarely performed and is generally condemned, as it completely obliterates the necessary rotation of the clavicle, severely limiting forward elevation and abduction of the upper extremity.

Phased Post-Operative Rehabilitation Protocols

The success of a sternoclavicular joint reconstruction is as dependent on the post-operative rehabilitation protocol as it is on the surgical execution. The healing of the autograft or allograft within the osseous tunnels and the maturation of the imbricated capsular tissues require strict protection from the massive lever-arm forces generated by the upper extremity. Rehabilitation is divided into four distinct phases, prioritizing graft protection early and functional restoration late.

Phase I: Maximum Protection (Weeks 0 to 4)
Immediately post-operatively, the patient is placed in a strict shoulder immobilizer or a specialized sling. A figure-of-eight brace may be added to maintain the shoulders in a retracted position, minimizing anterior translational forces on the healing SC joint. During this phase, active forward elevation, abduction, and extension of the shoulder are strictly prohibited. Rehabilitation is limited to active range of motion of the cervical spine, elbow, wrist, and hand to prevent distal stiffness. Gentle, sub-maximal scapular retractions are initiated to maintain periscapular muscle tone without stressing the SC joint.

Phase II: Controlled Motion (Weeks 4 to 8)
At the four-week mark, clinical and radiographic evaluations are performed. If the joint remains clinically stable, the patient is gradually weaned from the immobilizer for activities of daily living. Passive and active-assisted range of motion exercises for the glenohumeral joint are initiated. However, a strict limitation of forward elevation and abduction to 90 degrees is enforced to prevent excessive rotation of the clavicle, which could stretch the maturing graft. Submaximal, pain-free isometric exercises for the deltoid and rotator cuff are introduced.

Phase III: Progressive Strengthening (Weeks 8 to 12)
Assuming complete clinical stability and absence of pain at the SC joint, the 90-degree restriction is lifted, and the patient progresses to full active range of motion in all planes. Progressive resistance exercises are initiated, focusing on the rotator cuff, deltoid, and periscapular stabilizers (rhomboids, trapezius, serratus anterior). Closed kinetic chain exercises, such as wall push-ups and rhythmic stabilization drills, are highly effective in this phase for restoring proprioception and dynamic stability to the shoulder girdle without placing excessive shear stress on the SC joint.

Phase IV: Return to Function (Months 3 to 6)
The final phase focuses on sport-specific or occupation-specific functional restoration. Heavy lifting, pushing, pulling, and contact sports remain restricted until a minimum of 4 to 6 months post-operatively. Return to full unrestricted activity is contingent upon several criteria: absolute lack of pain at the SC joint, symmetrical full active range of motion, recovery of at least 90% of contralateral shoulder strength, and radiographic maintenance of the anatomical reduction. For overhead athletes or heavy laborers, a functional capacity evaluation or sport-specific biomechanical assessment is highly recommended before final clearance is granted.

Summary of Landmark Literature and Clinical Guidelines

The contemporary management of sternoclavicular joint instability is built upon a foundation of landmark biomechanical studies, epidemiological reviews, and evolving clinical guidelines. A thorough understanding of this literature is essential for the academic orthopedic surgeon to justify treatment algorithms and optimize patient outcomes.

The foundational work regarding the pediatric and young adult variant of this injury was established by Rockwood. His extensive epidemiological and radiographic studies definitively documented that the medial clavicular epiphysis is the last physis to close. Rockwood's axiom—that an apparent SC joint dislocation in a patient under 25 years of age should be treated as a physeal fracture until proven otherwise—remains a cornerstone of modern orthopedic teaching. This distinction is critical because physeal fractures possess massive remodeling potential and heal robustly with conservative management, whereas true ligamentous disruptions do not.

The paradigm shift away from hardware fixation was driven by the sobering reports of Worman and Leagus, as well as Brown and Omer. Their comprehensive reviews of complications following SC joint surgery highlighted the unacceptable and frequently fatal risks associated with transarticular smooth pins. These papers single-handedly changed the standard of care, establishing the absolute contraindication of K-wire fixation and paving the way for the development of modern soft-tissue reconstructive techniques. The biomechanical rationale for these soft-tissue reconstructions was later solidified by Spencer and Kuhn, whose cadaveric sectioning studies definitively identified the posterior capsule as the primary restraint to both anterior and posterior translation, dictating that any successful surgery must address this specific anatomical structure.

Current consensus guidelines, supported by the American Academy of Orthopaedic Surgeons (AAOS) and the Orthopaedic Trauma Association (OTA), strongly advocate for a multidisciplinary approach to posterior dislocations. The routine use of CT Angiography (CTA) for all posterior dislocations is now considered the standard of care to rule out occult vascular injury. Surgically, the literature has coalesced around the figure-of-eight autograft or allograft reconstruction as the most biomechanically sound and clinically reliable technique. Recent biomechanical studies have further validated the use of non-absorbable suture tape augmentation (InternalBrace) in conjunction with biological grafts, demonstrating superior ultimate load to failure and reduced cyclic elongation, representing the current cutting edge of sternoclavicular joint reconstruction.