Intrathoracic Fracture-dislocation of the Humeral Head:A Case Report and Review of the Literature

Intrathoracic displacement of a humeral head fracture is extremely rare.Only slightly more 30 have been Because few have been reported, there is no consensus on how to treat this injury. The etiology, injury mechanism, related lesions and treatment of the injury are diverse.


Abstract
Background Intrathoracic displacement of a humeral head fracture is extremely rare.Only slightly more than 30 cases have been reported. Because few cases have been reported, there is no consensus on how to treat this injury. The etiology, injury mechanism, related lesions and treatment of the injury are diverse.

Case presentation
A 73-year-old woman presented with multiple fractures of the left ribs, bilateral lung contusions, extensive emphysema of the anterior and posterior chest wall, massive left hemopneumothorax, fracturedislocation of the proximal humerus and intrathoracic displacement of the humeral head.The patient was sent to the operating room for emergency thoracotomy surgery. The head of the humerus was con rmed to be completely removed from the thoracic cavity during the operation. After discussion with the orthopedic surgeon, the humeral head was discarded considering avascular necrosis, and open reduction and internal xation were not performed.Three weeks later, the orthopedic surgery team performed reverse shoulder arthroplasty.During follow-up, the patient's shoulder was free from pain, and its range of movement (ROM) included 110° exion, 70° abduction, 35° external rotation and 50° internal rotation.

Conclusions
Intrathoracic displacement of the humeral head due to proximal humeral fracture is a very rare and serious trauma that requires multidisciplinary treatment. Considering the extremely high risk of humeral head necrosis, actively removing broken bone fragments of the humeral head in the early stage is recommended, and we advocate for shoulder arthroplasty for elderly patients. Detailed preoperative evaluations and individualized operation plans should be made to achieve the best effect.
The purpose of this study is to review published cases to examine the etiology, mechanism, related injuries and treatment of this rare injury. This study described a patient who suffered an intrathoracic fracture-dislocation of the humeral head after a high-energy tra c accident. After stabilizing the patient with the ATLS regimen, the patient was sent to the operating room for emergency thoracotomy surgery. A thoracic drainage tube was inserted and xed in the sixth intercostal space of the left axillary midline after complete hemostasis. The third and fourth ribs were xed with a rib embracing xator. The operation was successful, and the patient was transfused with 370 mL plasma and 5 units of packed red cells. Subsequently, the patient was further treated in the intensive care unit.

Case Presentation
The head of the humerus was con rmed to be completely removed from the thoracic cavity during the operation (Fig. 4). After discussion with the orthopedic surgeon, the humeral head was discarded considering avascular necrosis, and open reduction and internal xation were not performed. Three weeks later, electromyography (EMG) showed normal axillary nerve. Thus, the orthopedic surgery team performed reverse shoulder arthroplasty (Fig. 5). The patient is being well after reoperation.
Postoperative rehabilitation protocol: 0 ~ 6w after surgery: Patients were educated to make them understand the signi cance of postoperative rehabilitation. It includes boxing pump, assisted exion and extension, pendulum movement, active exion and extension of elbow and wrist, shoulder abduction pillow and shrug. Oral celebrex was given to patients within 3 weeks after surgery to reduce pain and prevent ectopic ossi cation. 7 ~ 12w after operation: Assisted external rotation, deltoid isometric contraction, table cleaning exercises and wall climbing exercises.At the nal follow-up, the patient's shoulder was free from pain, and its range of movement (ROM) included 110° exion, 70° abduction, 35°e xternal rotation and 50° internal rotation.

Discussion And Conclusions
Humeral head fracture-dislocation and penetration into the chest are injuries that have been rarely reported in the literature. To date, only 30 cases have been recorded in the literature. No treatment guidelines are currently available, there is a high variability in the management of these patients, even diametrically opposed treatment options.Treatment has to be individualized for each patient.
The literature on this subject is limited, so the mechanism of the injury has not been elucidated.
Hardcastle et al. [31] believed that the occurrence of injury can be divided into two stages. First, a drop in forced abduction with external rotation causing dislocation and moves the humeral head toward the chest,and then a sharp adduction leads to fracture of the humeral head. Glessner [32] and Patel et al [15] proposed a similar mechanism, in which a forced abduction dislocated the shoulder into the chest cavity, and in the process of impact against the ribs would be when the fracture took place. Karr et al. [7] proposed a two-stage mechanism of injury. When the elbow was in the abduction position, the humeral head was fractured and dislocated, and then the shoulder hit the ground, causing the rib to fracture and the humeral head to be embedded in the chest cavity. As all these authors have concluded, a single traumatic force is unlikely to cause this type of injury [21]. The injury mechanism of our case was associated with high-energy trauma of abduction and external rotation of the shoulder, and there was no need for a reduction operation. Spontaneous dislocation reduction occurred in most cases, and no reduction operation was needed.
This mechanism often leads to fracture-dislocation of four parts of the proximal end of the humerus. As an exception, two cases of two-part fracture-dislocation were reported [1,26], and one case of three-part fracture-dislocation [31] and separation fracture of proximal humerus epiphysis [30] were reported in the literature. Humeral head fracture-dislocation and chest penetration often occur due to high-energy injuries, mostly accompanied by related injuries. Pneumothorax, hemothorax and other lung injuries almost always coexist. It is often associated with thoracic and limb injuries. Fractures of the scapula, humeral shaft, elbow, wrist, pelvis and tibial plateau have also been reported. Vascular injuries, including aortic compression and subclavian artery and costal neck trunk injuries, were also reported. Cases of rupture of the main bronchus have also been reported in the literature [24]. In addition to humeral head displacement to the ipsilateral thoracic cavity, there are other special cases, such as 1 case of the humeral head in the retroperitoneal space [33] and 2 cases of movement to the contralateral thoracic cavity [4,5].
When a nerve injury occurs, the axillary nerves generally tend to be involved, which is very di cult to evaluate in the initial physical examination. There have also been reports of median nerve, ulnar nerve and secondary brachial plexus trunk injuries. Most patients spontaneously recover without surgery, although other patients do not fully recover [3,4,6,27,34]. In this paper, EMG showed normal axillary nerve.
Treatment of the humeral head differed from previous reports. There is no agreement on whether to remove the humeral head, most of which is removed to prevent potential complications. In early and subsequent individual cases, fragments of the humeral head remained in the chest [1,7,10,15,27]. Some scholars have suggested that it is necessary to remove fragments only when there are cardiopulmonary complications. The reason for removal of bone fragments from the humeral head is that there may be related complications, such as infection or foreign body reactions [18]. It has been reported that the retained humeral head was removed 6 weeks late, and was embedded in the pulmonary parenchyma with extensive adhesion, requiring extensive resection [35]. We believe that fragments of the humeral head should be actively removed at an early stage. Although humeral head fragments are sterile, bone fragments may become a potential focus of infection, complicating treatment. Extraction can be performed by thoracotomy or thoracoscopy. Ideally, minimally invasive methods, such as video-assisted thoracoscopy, should be adopted to remove the humeral head. After removing it, subsequent techniques for shoulder reconstruction will depend on speci c conditions of the patient.
In terms of treatment of fracture of the proximal humerus, a surgeon must consider the risk of humeral head necrosis when determining the surgical plan, and vitality of the humeral head determines treatment of the proximal humerus. In three-or four-part displaced fractures, there is high risk of ischemic necrosis or nonunion of the head. Humeral head necrosis increased from approximately 25% of three-part fractures to nearly 60% of four-part fractures [34,36]. In the orthopedic literature, there is still a great deal of controversy about which surgical option is the most appropriate. Open reduction and internal xation are possible in younger patients [5,22,26,30,31]. In published articles, the majority of cases were treated with hemiarthroplasty of the glenohumeral joint [2-6, 8, 9, 11-13, 18-21, 23, 27-29], and one patient was treated with reverse shoulder arthroplasty [12].
Intrathoracic displacement of the humeral head due to proximal humeral fracture is a very rare and serious trauma that requires multidisciplinary treatment. Considering the extremely high risk of humeral head necrosis, actively removing broken bone fragments of the humeral head in the early stage is recommended, and we advocate for shoulder arthroplasty for elderly patients. Detailed preoperative evaluations and individualized operation plans should be made to achieve the best effect. Ethics approval and consent to participate: The experimental protocol was established, according to the ethical guidelines of the Helsinki Declaration and was approved by the Human Ethics Committee of Lishui Central Hospital,Written informed consent was obtained from individual or guardian participants.
Consent for publication:We obtained written consent from the participants before publishing this information.
Authors Contributions: WC collected the data of the case and consulted relevant literature. YRF was a major contributor in writing the manuscript. All authors read and approved the nal manuscript.
Availability of data and materials:All the data needed to achieve the conclusion are presented in the paper.
Funding: Not applicable Competing Interests: The authors declare that they have no competing interests.