Spontaneous reduction of type I traumatic manubriosternal joint dislocation: A case report

Abstract

We report the case of a 68-year-old male who sustained blunt chest trauma in a motor vehicle accident and presented with severe chest pain, dyspnea, pneumothorax, and multiple rib fractures. Imaging revealed a complete type I manubriosternal joint dislocation with an associated retrosternal hematoma. Urgent surgical intervention was planned; however, it was delayed for several hours because of inadequate fasting time. During this interval, the patient’s anterior chest wall prominence subsided, and the patient’s hemodynamic status improved. Follow-up chest computed tomography demonstrated complete spontaneous reduction of the manubriosternal joint dislocation. The patient was subsequently managed conservatively with analgesics, respiratory exercises, and close monitoring. He recovered without complications and remained stable on follow-up imaging 2 months later. This case highlights the rare occurrence of spontaneous reduction in traumatic manubriosternal joint dislocation.

Background

Sternal fractures are painful injuries observed in approximately 3%–8% of patients with blunt trauma.^1–3 The most common mechanism of injury is direct blunt chest trauma resulting from motor vehicle accidents.^4,5 Sternal fractures most frequently involve the sternal body, whereas fractures of the manubrium and xiphoid process are less common.^1,3,6 Traumatic manubriosternal joint (MSJ) dislocation is particularly rare. ⁷ MSJ dislocations are classified into two types: in a type I dislocation, the sternal body is displaced dorsally, whereas in type II dislocation, the sternal body is displaced ventrally relative to the manubrium. ⁸

Clear indications for the management of sternal fractures have not been fully established, and most cases are treated conservatively with appropriate analgesics.^3–5,9–11 However, surgical fixation may be considered in cases of unstable fractures, thoracic wall instability, fracture displacement or persistent dislocation, sternal deformity, respiratory insufficiency, severe pain, or fracture nonunion.^2–4,7,12 In this case report, we describe a rare case of MSJ dislocation with hemodynamic instability that spontaneously reduced 3 h after the injury.

Case presentation and methods

A 68-year-old male involved in a motor vehicle accident presented to the trauma center with severe chest pain and dyspnea. He had fallen approximately 2 m with the vehicle and sustained a severe impact to the anterior chest against the steering wheel. Upon arrival at the emergency department, his oxygen saturation was 91% while receiving oxygen via a 7 L/min face mask, and his anterior chest wall appeared markedly protruded. The patient had no significant past medical history other than hypertension. Initial arterial blood gas analysis showed a pH of 7.376, pCO₂ of 33.9 mmHg, pO₂ of 68.1 mmHg, and a lactate level of 2.3 mmol/L. The patient’s vital signs were relatively stable, with a systolic blood pressure (SBP) of 110 mmHg and a diastolic blood pressure (DBP) of 80 mmHg; however, bradycardia with a heart rate (HR) of approximately 40 beats per minute and tachypnea with a respiratory rate (RR) of 29 breaths per minute were noted. Chest computed tomography (CT) revealed a traumatic pneumothorax in the right thoracic cavity and multiple rib fractures involving the right second to seventh ribs (Figure 1). Particularly, the patient’s MSJ was completely dislocated in a type I pattern and was accompanied by a small retrosternal hematoma (Figure 2).

Figure 1.

Initial chest computed tomography image. The red arrow indicates a right fourth rib fracture, and the blue arrow indicates a traumatic pneumothorax.

Figure 2.

Initial chest computed tomography images. Left: three-dimensional rendering image showing the manubriosternal joint dislocation with multiple linear rib fractures of the right chest wall. Right: sagittal view showing marked protrusion of the anterior chest wall with a retrosternal hematoma.

After performing a closed thoracostomy on the right chest, urgent surgical management of the MSJ dislocation was planned. However, due to insufficient fasting time (nil per os (NPO)), the procedure was postponed for approximately 3 h. During this period, the patient was transferred to the surgical intensive care unit (SICU).

After the 3-h interval agreed upon with the anesthesiology team, when we returned to the SICU to transfer the patient to the operating room, the previously protruded anterior chest wall appeared reduced. His vital signs had stabilized, with an SBP of 140 mmHg, a DBP of 80 mmHg, an HR of 60 beats per minute, and an RR of approximately 14 breaths per minute. The patient also reported no pain.

Surgery was briefly delayed to obtain a noncontrast chest CT scan, which revealed complete spontaneous reduction of the MSJ dislocation (Figure 3). The patient was advised to maintain an upright posture and perform deep-breathing exercises. He was transferred to the general ward the following day, and conservative management, including analgesics, was continued. He was discharged on hospital day 9 without complications. At approximately 2 months after discharge, a follow-up lateral sternal X-ray in the outpatient department confirmed that MSJ stability was well-maintained (Figure 4).

Figure 3.

Noncontrast chest CT obtained 3 h after closed thoracostomy and before surgical management of MSJ dislocation. Left: chest CT showing closed thoracostomy with spontaneous reduction of the MSJ dislocation. Right: reduction of the MSJ with normalization of the previously protruded anterior chest wall.

Figure 4.

Outpatient follow-up lateral sternum radiograph at 2 months.

The reporting of this study conforms to the Case Report (CARE) guidelines. ¹³

Discussion

Traumatic MSJ dislocation is extremely rare; therefore, no definitive treatment guidelines have been established. In cases of incomplete MSJ dislocation, conservative management with analgesics may be considered; ¹⁴ however, in cases of complete displacement, pain is often severe and surgical treatment may be required.^5–7,15 Several fixation techniques have been described, with wiring and plating being the most commonly used methods.^5,7,12 Recent studies suggest that, compared with wiring, plating results in improved bone healing and lower rates of complications and nonunion.^4,5,12,16 However, plating may be associated with higher initial costs and longer operative times. ¹⁷ We believe that the choice between plating and wiring should be individualized based on the morphology of the sternal fracture, the surgeon’s experience, and patient-specific factors.

In general, most sternal fractures are managed conservatively, and cases requiring surgery are rare. Therefore, clear recommendations regarding the optimal timing of surgery have not been established. However, in orthopedic trauma, including hip fractures, and in patients with multiple rib fractures, several studies have demonstrated the benefits of performing surgery within 3 days of injury.^18–21 Accordingly, in our trauma center, when surgery is indicated for sternal fractures, we aim to perform the procedure as early as possible.

Retrosternal hematoma is a common finding in sternal injuries, particularly in fractures involving the sternal body and may be associated with severe complications such as rupture of the internal thoracic artery. Therefore, accurate radiologic evaluation is essential.^6,22–25

The coexistence of cardiac tamponade due to blunt cardiac injury and a concomitant sternal fracture presents a challenging clinical scenario. In such cases, a sternal fracture may complicate a standard median sternotomy. Given the rarity of these cases, there are no established guidelines regarding the choice of incision or the optimal method of postoperative sternal repair. ²⁶

Recurrent MSJ dislocation associated with postural changes has been reported in a patient with rheumatoid arthritis. ²⁷ However, to the best of our knowledge, traumatic MSJ dislocation with spontaneous reduction has not been previously reported. Unlike chronic conditions such as rheumatoid arthritis, our case occurred in acute phase immediately after blunt chest trauma, during which the patient presented with severe chest pain, dyspnea, and bradycardia. Therefore, we initially planned urgent surgical intervention rather than conservative management with analgesics. If surgery had not been delayed because of the patient’s NPO status, sternal fixation using an H-shaped titanium plate would have been performed. The spontaneous reduction was an entirely unexpected outcome.

Despite the spontaneous reduction observed in our case, our treatment strategy remained unchanged. Surgical intervention should be prioritized in patients with complete sternal fracture dislocation who present with respiratory difficulty accompanied by flail motion^28,29 or intolerable pain.

Conclusion

Most traumatic sternal fractures are managed conservatively, although surgical intervention may be required in selected cases. Therefore, individualized assessment is essential for each patient. Although we report a spontaneous reduction of a type I traumatic MSJ dislocation in this report, this outcome is unprecedented, and further studies are warranted to clarify the indications for surgical management of sternal fractures.