|Year : 2018 | Volume
| Issue : 2 | Page : 75-78
Posterior fracture dislocation of shoulder with anatomical neck fracture
Yashwant Singh Tanwar1, Atin Jaiswal2, Yatinder Kharbanda1, Anil Panda1
1 Department of Orthopedics, Apollo Hospital, New Delhi, India
2 Department of Orthopedics, Vivekananda Polyclinic and Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
|Date of Web Publication||5-Jul-2018|
Yashwant Singh Tanwar
Department of Orthopedics, Apollo Hospital, H NO. 299, Pocket B, DDA Flats, Sarita Vihar, New Delhi - 110 076
Source of Support: None, Conflict of Interest: None
Posterior fracture dislocation of anatomical neck of humerus is a rare injury and possesses challenges in management due to the scarcity of literature and absence of any recommended guidelines for such injuries. Treatment options available are internal fixation and hemiarthroplasty depending on injury pattern, duration of injury, bone stock available for secure fixation, and vascularity of the head fragment. We present a case report of posterior fracture dislocation of anatomical neck humerus in a 35-year-old male patient treated by open reduction and internal fixation by deltopectoral approach. This case report is unique as the fixation method (Herbert screws) used in this case resulted in a good functional outcome and has not been described previously in literature for this injury pattern.
Keywords: Anatomical neck humerus, fracture dislocation, headless compression screw
|How to cite this article:|
Tanwar YS, Jaiswal A, Kharbanda Y, Panda A. Posterior fracture dislocation of shoulder with anatomical neck fracture. Apollo Med 2018;15:75-8
| Introduction|| |
Posterior dislocations are uncommon injuries of proximal humerus, with a reported incidence of 2%–5% of all shoulder dislocations. Posterior shoulder fracture dislocations are even rarer, accounting for approximately 0.9% of shoulder fracture dislocations. The overall incidence of posterior fracture dislocations was 0.6/100,000 population/year in a study by Robinson et al. Posterior dislocations are usually the end result of epileptiform seizures or electric shock injuries. However, posterior fracture dislocation of the proximal humerus with large osteochondral fragment resulting from trauma is a rare and potentially complicated injury. Such injury occurs when a posteromedially directed force is exerted on proximal humerus resulting in extrusion of head from the glenoid along with impaction on the posterior glenoid. Unlike such injuries in hip where posterior acetabular wall readily fractures, in the shoulder, the hard and shallow glenoid acts as an anvil resulting in osteochondral fracture of the humeral head or reverse Hill sachs lesion. Such fracture pattern is mostly seen in younger patients with good bone stock.
Various methods of fixation for such injuries have been described in literature, each with its own advantages and disadvantages. Optimal approach and fixation strategy is controversial and has to be tailor made according to the location, size, and site of fracture fragments. Preoperative computed tomography (CT) scan better delineates the fracture pattern and is beneficial in preoperative planning and to avoid intraoperative surprises. One such injury pattern occurring in a 35-year-old male treated by open reduction and internal fixation with headless screws through the cartilage of humeral head is described in the present case report. This case report is unique as the fixation done in this case was through the articular cartilage of the humeral head, which has not yet been reported in literature and it will add to the available management options for treating such rare fractures.
| Case Report|| |
A 35-year-old male presented to the emergency department with injury to his left shoulder following fall from a motorbike. On inquiring about the mode of trauma, the patient informed that, while driving at a high speed, his motorbike lost control and he tried to resist collision against a pole through his outstretched palm hitting against a pole. He was supporting his left elbow with the right hand and movements at the left shoulder were extremely painful. There was swelling and ecchymoses over the lateral aspect of the left shoulder with some superficial abrasions. There were no associated injuries and no distal neurovascular deficit in the affected limb. The limb was splinted and radiographs were done which showed dislocation of the left shoulder with discontinuous contour of the humeral head [Figure 1]. On suspicion of osteochondral or head-split fracture, closed reduction was not attempted in view of creating another vascular insult to the already jeopardized fragments. CT scan of the patient revealed posterior fracture dislocation of the shoulder with single large anatomical neck fragment lying in contact with the posterior glenoid rim-type 1 posterior fracture dislocation variant  (Neer's two-part anatomic neck fracture) [Figure 2].
|Figure 1: X-rays at the time of presentation showing posterior dislocation of shoulder and irregular outline of humeral head giving rise to suspicion of fracture|
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|Figure 2: A three-dimensional reconstruction computed tomography scan showing the posterior humeral head fracture dislocation clearly|
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The patient and attendants were counseled regarding the injury and its possible outcomes. They were explained regarding the possible treatment options including hemiarthroplasty and head salvage surgery in the form of open reduction and internal fixation. They were also counseled regarding the risk of osteonecrosis and revision surgeries in case a humeral head preservation surgery was performed. After in-depth discussion, it was decided that a humeral head preservation surgery was a more viable option considering the patient's age, early presentation, occupational needs, and good bone quality.
The patient was given general anesthesia and the affected part was painted and draped in beach chair position. Deltopectoral approach was utilized and the joint was opened with anterior capsulotomy. Intraoperative image intensifier views confirmed the CT findings and showed a large posteriorly dislocated humeral head fragment [Figure 3]. The arm was internally rotated so that the fracture surface faced each other in the best possible contact and two k-wires were inserted from the greater tuberosity area directed posteromedially so as to engage the humeral head fragment securely. The arm was then externally rotated so that the head fragment was rotated anteriorly and brought into vision through the anterior capsulotomy incision. K-wires were then partially withdrawn, disengaging the humeral head fragment. Now, the fracture was anatomically reduced under vision with minimal manipulation taking care not to disturb a small posterior capsular and periosteal soft-tissue attachment to the osteochondral head fragment. The previously placed K-wires were advanced into the head fragment, provisionally securing the fracture reduction. A small k-wire was drilled in the head fragment and removed to see that there was back bleeding as an evidence of preserved vascularity. The guidewires for Herbert screws (Synthes 2.4 mm) were inserted and the position was checked under image intensifier. After drilling with a cannulated drill over the guidewires, four Herbert screws (2.4 mm) were inserted through the articular surface into the distal fragment with enough countersinking so as not to erode the glenoid cartilage [Figure 4]. The shoulder was moved through full range of motion to check the stability of fixation and for any possible mechanical block caused by the screws. Soft tissues were repaired and the shoulder was kept in an immobilizer for 3 weeks to allow healing of posterior capsule. Gradual pendulum exercises were started from the 3rd postoperative week, and full active and passive mobilization of the shoulder was started at 6 weeks. At 3-month postoperative period, the patient had recovered full shoulder range of motion. Till the last follow-up at 2 years, there was no evidence of osteonecrosis [Figure 5] and the Disabilities of the Arm, Shoulder and Hand score at the last follow-up was 4.5.
|Figure 3: Intraoperative image intensifier view showing the large anatomical head fragment clearly|
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|Figure 4: Intraoperative image intensifier views after reduction of fracture dislocation and fixation with four 2.4-mm Herbert screws|
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|Figure 5: Follow-up X-ray at 2 years showing union of fracture and no evidence of osteonecrosis|
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| Discussion|| |
Posterior fracture dislocation of proximal humerus is a very rare entity, so no evidence-based guidelines are available for suitable approach and management of these fractures. Such injuries occur most commonly in young males as a result of seizures, secondary to drug withdrawal, hypoglycemia, or due to high-velocity injuries. In this injury, as the humeral head engages on the posterior glenoid, it results in an osteochondral fracture which usually starts from the anterior part of the humeral head propagating to the anatomical neck and finally resulting in a posterior dislocation. It is usually associated with avulsion of posterolateral capsule and labrum resulting in reverse Bankart lesion. Usually, there is adequate attachment and continuity of capsule and periosteal sleeve to provide adequate blood supply to the head fragment. This preserved blood supply may provide revascularization to the humeral head, which along with creeping substitution saves humeral head from avascular necrosis. Hence, Neer suggested that closed reduction of the posterior fracture dislocation of humerus should not be attempted so as to prevent further damage to the blood supply and instead a direct open reduction should be resorted to. Our case was type 1 posterior fracture dislocation where there is an anatomical neck fracture along with posterior dislocation. Accurate reconstruction of the articular surface restored joint stability and gave excellent clinical results.
Large humeral head osteochondral fracture fragments require accurate reduction and internal fixation while preserving the already damaged blood supply. We did not disturb the posterior capsular attachment and periosteal hinge to the head which had been the only source of blood supply to the fragment which saved the head from osteonecrosis. Evidence of back bleeding from the head fragment may give a clue regarding the vascularity of the fragment and may help in deciding the management. Some case reports have mentioned fixation of the head, with implants placed from intact lateral proximal humeral metaphyses directed posteromedially, but we believe that in humeral head the best purchase of bone is in subchondral region and, by inserting screws from the articular surface, the surgeon can ascertain the purchase of implant better than the latter method. In addition, biomechanically, it is always better to lag the smaller fragment to the main shaft, rather than the other way around; as the former method results in better compression along the fracture site. Even if osteonecrosis does develop later, many a times, it remains asymptomatic as shoulder is not a weightbearing joint and causes minimal limitations and pain. Therefore, although both the options of humeral head salvage and hemiarthroplasty should be discussed with the patient, a strong favor should be given to salvage surgery. In case of doubt regarding the vascularity, especially in delayed presentations and in elderly patients, primary hemiarthroplasty is also an attractive alternative as both the tuberosities are attached to the shaft fragment which allows early rehabilitation irrespective of the fear of tuberosity healing. However, there are case reports illustrating that, even with complete disruption of the vascular supply to the humeral head, revascularization after osteosynthesis is possible. The worst scenario in such cases is failed primary osteosynthesis leading to arthroplasty. Before attempting for osteosynthesis, the factors which surgeon needs to keep in mind are the surgical approach, method of fixation, direction of fixation, and a backup plan and consent for hemiarthroplasty. We hope that this case report will add to the scarce literature available on this injury and its management options.
A well-informed consent was obtained from the patient included in the study.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understand that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]