Intrathoracic displacement of the humeral head in a trauma patient.

Sir,

We read with interest the article by Jun-Song et al.1 Recently, we treated a patient with a similar diagnosis and would like to share our experience and possible mechanism of injury.

A 79-year-old woman was admitted to an emergency department after falling on her outstretched right arm. She reported that it was “stuck” in an overhead (abducted) position and she managed to pull her arm right into the side of her body. On examination, there was significant generalized painful swelling around the right shoulder a decrease in the range of motion, generalized vague right chest pain and crepitation on right chest wall. Vital findings were normal and there were no distal neurovascular deficit. Initial X-rays and computed tomography (CT) imaging of right shoulder demonstrated a comminuted proximal humeral fracture, hemopneumothorax, third rib fracture and subcutaneous emphysema related to rib fracture [Figure 1]. Hemopneumothorax was promptly treated and surgery was scheduled to treat the comminuted humeral fracture. In her followup chest X-ray film, both the pneumothorax and hemothorax had improved after treatment. In the same X-ray film, we also observed a mass located in the middle peripheral part of the the right lung [Figure 2]. An enhanced 3D-CT imaging was performed and a well defined, 3.5 cm in diameter, semi-spheric shaped osseous structure was seen. The clinical scenario and findings on 3D-CT, corelated that the intrathoracic lesion was the fractured and dislocated humeral head [Figure 3]. The intrathoracic displaced humeral head was not identified during the first CT scan since only the right shoulder region was scanned. During the preoperative period, the patient did not report dyspnea or any other sign or symptom that might indicate injury to her right lung. A mini-thoracotomy was performed for removal of the humeral head and hemiarthroplasty was subsequently performed. At the 18-month followup the patient reported full range of motion and no pain [Figure 4].

Figure 1

X-ray showing the right humeral fracture (thick arrow) and right third rib fracture (thin arrow), hemo-pneumothorax, subcutaneous emphysema

Figure 2

Followup chest X-ray after treatment of the hemopneumothorax demonstrated a mass localized in right thorax

Figure 3

3D volume rendering technique computed tomography images showing (a) A right proximal humeral and right third and fourth rib fractures and (b) intrathoracic location of a fractured and displaced humeral head

Figure 4

18-month followup X-ray of shoulder and right thorax demonstrated no postoperative complications. The patient was pain-free and had a full range of motion of her right shoulder

Cases like these are rare in the literature due to the complex mechanism of action that resulted in the above described clinical scenario; the injury initiated with an axial stress loading of outstretched arm and this trauma resulted in a nondisplaced fracture of the humeral head and subsequent dislocation from the glenohumeral joint. With continuity of force along the humerus, the humeral head and proximal part of humeral shaft fractured the ribs. After such injury, the patient's attempt to relocate her arm by levering her arm into adduction caused the separation of the humeral head from proximal part of the humerus. This described mechanism has been previously described.23 This type of injury can be further described as the mechanism of action required to open a capped bottle with a bottle opener. In this case, the humeral head (bottle cap) was “opened” using both the ribs (bottle cap opener).

In regards to the fact that the complete diagnosis was missed during the first CT scan, we must emphasize the need to perform a detailed evaluation of patients and careful assessment of the imaging studies. In addition, both orthopedic surgeons and radiologists should suspect any complications related to the clinical scenario based on the patient's history.