Overview
Closed fracture subluxation of the sternum is a complication characterized by partial dislocation of the sternum following trauma or surgical procedures, particularly median sternotomies. This condition can lead to significant chest wall instability, impaired respiratory function, and increased risk of sternal dehiscence and infection. It predominantly affects patients who have undergone cardiothoracic surgeries or experienced high-energy blunt chest trauma. Early recognition and appropriate management are crucial to prevent complications and ensure optimal recovery. This matters in day-to-day practice as timely intervention can mitigate severe morbidity and reduce hospital stay. 12Pathophysiology
Closed fracture subluxation of the sternum typically arises from excessive mechanical forces that exceed the structural integrity of the sternum, leading to microfractures or dislocations without complete separation of bone segments. In surgical contexts, particularly after median sternotomies, the healing process can be compromised by factors such as inadequate bone stabilization, excessive physical stress (e.g., coughing, deep breathing), and underlying comorbidities like osteoporosis. The resultant instability disrupts the normal alignment and function of the chest wall, affecting respiratory mechanics and potentially leading to sternal dehiscence. Biomechanical studies highlight that conventional wire cerclage closure may not adequately resist pathologic displacement under physiological loads, underscoring the need for enhanced stabilization methods 2.Epidemiology
The incidence of closed fracture subluxation specifically is not well-documented in large epidemiological studies, but it is recognized as a complication following approximately 0.5% to 2% of median sternotomies 2. Patients at higher risk include those with osteoporosis, advanced age, and those undergoing multiple sternotomies. Geographic and sex distributions are not distinctly delineated in the literature, but clinical experience suggests that older populations and those with significant comorbidities are disproportionately affected. Trends over time indicate a growing interest in innovative stabilization techniques to mitigate this complication, reflecting advancements in surgical closure methods 12.Clinical Presentation
Patients with closed fracture subluxation of the sternum often present with localized chest pain, particularly over the sternotomy site, exacerbated by movement or deep inspiration. Other typical symptoms include dyspnea, particularly on exertion, and signs of respiratory compromise such as tachypnea or use of accessory muscles. Atypical presentations might include referred pain to the shoulder or arm, and in severe cases, subcutaneous emphysema or signs of sternal dehiscence like wound separation. Red-flag features include fever, purulent discharge from the wound, and hemodynamic instability, which warrant immediate concern for infection or mediastinitis 12.Diagnosis
The diagnostic approach for closed fracture subluxation involves a combination of clinical assessment and imaging techniques. Clinically, suspicion arises from the history of recent sternotomy or trauma, coupled with the aforementioned symptoms. Diagnostic criteria include:Clinical Criteria: Pain localized to the sternotomy site, exacerbated by movement, and associated with respiratory distress.
Imaging:
- Chest Radiography: May show subtle signs of sternal displacement or widening of the sternotomy gap.
- CT Scan: Provides detailed visualization of bony structures and can confirm subluxation with measurements of displacement (typically >2 mm considered pathologic).
- Biomechanical Testing: In research settings, biomechanical testing under simulated physiological loads can quantify instability 2.Differential Diagnosis:
Sternal Dehiscence: Distinguished by visible wound separation and often associated with signs of infection.
Pneumothorax: Presents with sudden onset of chest pain and dyspnea, often with tracheal deviation or decreased breath sounds on affected side.
Pericarditis: Characterized by pleuritic chest pain, pericardial friction rub, and ECG changes 12.Management
Initial Management
Stabilization: Immobilize the chest with a supportive brace or chest binder to reduce movement and alleviate pain.
Pain Control: Administer analgesics such as NSAIDs or opioids as needed, titrated to patient response.
Monitoring: Closely monitor vital signs, respiratory function, and signs of infection.Intermediate Management
Enhanced Sternal Closure Techniques:
- Nitinol Thermoreactive Clips: Utilize these clips for secondary closure in cases of noninfective sternal dehiscence, offering a safe and efficient method to stabilize the sternum 1.
- Kryptonite Bone Cement: Consider using triglyceride-based porous adhesives to enhance stability, particularly in cases where conventional methods fail to prevent pathologic displacement 2.Refractory Cases / Specialist Referral
Surgical Intervention: In cases of persistent instability or recurrent subluxation, surgical revision with reinforced closure techniques may be necessary.
Orthopedic Consultation: For complex cases, consultation with an orthopedic surgeon may be required to address underlying bone issues or to perform definitive stabilization procedures.Contraindications:
Active infection or signs of mediastinitis.
Severe comorbidities precluding surgical intervention.Complications
Sternal Dehiscence: Recurrent instability leading to wound separation, requiring reoperation.
Infection: Superficial or mediastinal infections, necessitating prolonged antibiotic therapy and possibly surgical debridement.
Respiratory Failure: Prolonged respiratory compromise requiring mechanical ventilation.
Chronic Pain: Persistent discomfort post-recovery, potentially requiring long-term pain management strategies.Refer patients with signs of infection or recurrent instability to infectious disease specialists or cardiothoracic surgeons for prompt intervention 12.
Prognosis & Follow-up
The prognosis for patients with closed fracture subluxation is generally good with appropriate management, though outcomes can vary based on the severity of initial injury and adherence to stabilization protocols. Prognostic indicators include prompt diagnosis, effective stabilization techniques, and absence of complications like infection. Recommended follow-up intervals include:
Initial Follow-up: Within 2-3 weeks post-stabilization to assess wound healing and sternal stability.
Subsequent Follow-ups: Every 4-6 weeks until full recovery, focusing on respiratory function, pain levels, and signs of complications.Special Populations
Elderly Patients: Higher risk due to osteoporosis and comorbid conditions; require meticulous stabilization techniques and close monitoring.
Patients with Multiple Sternotomies: Increased risk of instability; consider advanced closure methods like nitinol clips or bone cement.
Pediatric Patients: Less common but requires careful assessment; growth plate considerations may necessitate specialized orthopedic input 12.Key Recommendations
Utilize Advanced Closure Techniques: Employ nitinol thermoreactive clips for secondary sternal closure in cases of noninfective subluxation to ensure stability and prevent recurrent instability (Evidence: Strong 1).
Enhance Sternal Stability: Consider the use of triglyceride-based porous adhesives to prevent pathologic displacement under physiological loads (Evidence: Moderate 2).
Close Monitoring Post-Procedure: Regularly monitor patients for signs of sternal instability, infection, and respiratory compromise, with follow-ups every 2-3 weeks initially (Evidence: Moderate 12).
Immediate Surgical Revision for Recurrent Instability: Refer patients with recurrent subluxation or dehiscence to cardiothoracic surgeons for surgical revision (Evidence: Expert opinion).
Pain Management and Immobilization: Implement appropriate pain control and chest immobilization to facilitate healing and reduce complications (Evidence: Moderate 1).
Consider Orthopedic Consultation: For complex cases, involve orthopedic specialists to address underlying bone issues (Evidence: Expert opinion).
Avoid Procedures in Active Infection: Do not proceed with advanced closure techniques if there is active infection or signs of mediastinitis (Evidence: Strong 1).
Tailored Approach for Special Populations: Adapt management strategies for elderly patients and those with multiple sternotomies, considering their increased risk factors (Evidence: Expert opinion).
Use Imaging for Confirmation: Confirm subluxation with CT scans or biomechanical testing to guide appropriate intervention (Evidence: Moderate 2).
Educate Patients on Symptoms: Instruct patients to report any worsening symptoms promptly, particularly signs of infection or respiratory distress (Evidence: Expert opinion).References
1 Gucu A, Toktas F, Eris C, Ata Y, Turk T. Nitinol thermoreactive clips for secondary sternal closure in cases of noninfective sternal dehiscence. Texas Heart Institute journal 2012. link
2 Fedak PW, Kolb E, Borsato G, Frohlich DE, Kasatkin A, Narine K et al.. Kryptonite bone cement prevents pathologic sternal displacement. The Annals of thoracic surgery 2010. link
3 Pilegaard HK, Licht PB. Can absorbable stabilizers be used routinely in the Nuss procedure?. European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery 2009. link
4 Sardari FF, Schlunt ML, Applegate RL, Gundry SR. The use of transesophageal echocardiography to guide sternal division for cardiac operations via mini-sternotomy. Journal of cardiac surgery 1997. link