Atraumatic Bilateral Anterior Shoulder Dislocation With Bilateral Greater Tuberosity Fractures Accompanied by the Diagnosis of Epilepsy: A Case Report

Introduction

Glenohumeral dislocations account for more than half of all dislocations presenting to the emergency department, and the vast majority occur in the anterior direction.^1,2 These injuries are frequently accompanied by rotator cuff lesions, capsulolabral damage, and greater tuberosity fractures. ³ Bilateral shoulder dislocations are quite rare and are most commonly reported in the literature as bilateral posterior dislocations. ⁴ Bilateral posterior shoulder dislocations are typically associated with epileptic seizures, electrical injuries, and other neurological events, resulting from violent muscle contractions and secondary trauma occurring during the episode. ⁴

In contrast, bilateral anterior shoulder dislocations are usually traumatic in origin and are much rarer than bilateral posterior dislocations.^4-6 Bilateral anterior shoulder dislocation related to epileptic seizures, accompanied by bilateral greater tuberosity fractures, has been reported only in a very limited number of cases in the literature. In some of the reported cases, the dislocation was attributed to a traumatic mechanism, whereas in others the presence of possible secondary trauma during the postictal period was not clearly established.^6-18 This uncertainty may lead to delayed diagnosis, particularly in patients without a clear history of trauma and in whom the seizure etiology is not initially recognized.

The aim of this case report is to present the successful management, with open reduction and internal fixation, of bilateral anterior shoulder dislocation accompanied by bilateral greater tuberosity fractures in a patient with no prior diagnosis of epilepsy who presented to the emergency department with loss of consciousness, in whom an epileptic seizure was not definitively diagnosed at the initial evaluation, and in whom no traumatic history was present. In addition, through this atypical case, we aim to highlight that while seizure-associated bilateral shoulder dislocation has been previously reported, simultaneous bilateral greater tuberosity fractures leading to the diagnosis of epilepsy remain exceedingly rare, underscoring the importance of thorough musculoskeletal evaluation in patients with new-onset seizures to prevent delayed diagnosis and functional impairment. Written informed consent was obtained from the patient for publication of this case and the accompanying images.

Case Presentation

A 23-year-old female patient, with no previously known medical conditions other than a preliminary diagnosis of attention deficit hyperactivity disorder, for which she was taking venlafaxine 75 mg once daily and methylphenidate 18 mg once daily, presented to our orthopedic clinic with bilateral shoulder pain persisting for one day following an episode characterized by loss of consciousness and convulsions. According to the patient’s history, one day prior to presentation she experienced a sudden loss of consciousness accompanied by generalized muscle contractions while sitting on a chair in a café. No history of trauma was reported by either the eyewitnesses present at the scene or the patient, and no record of trauma sustained during the seizure was documented in the emergency department records. She was transported to the emergency department by ambulance. After completion of acute medical treatment with a preliminary diagnosis of an epileptic seizure, she was discharged from the emergency department and referred to the neurology outpatient clinic for further evaluation.

On examination, both shoulders demonstrated a positive epaulette sign, with limited passive abduction (80°), absent internal and external rotation, and flexion restricted to 90°. Neurovascular status of both upper extremities was intact. The preoperative pain level was recorded as 4/10 on the Visual Analog Scale (VAS) with both shoulders in the dislocated position and increased to 9/10 during passive examination of the shoulders. Radiographs revealed bilateral anterior shoulder dislocation with associated bilateral greater tuberosity fractures (Figure 1).OPEN IN VIEWER

Both shoulders were reduced under sedation in the operating room using the Kocher maneuver. Post-reduction neurovascular examination was normal. Follow-up imaging demonstrated greater than 10 mm displacement of the greater tuberosity fragments with an associated risk of instability, and open reduction and internal fixation was therefore planned (Figure 1).

The surgical procedure was performed under general anesthesia with the patient in the beach-chair position. After sterile preparation of both shoulders, the fracture sites were exposed using a transdeltoid lateral approach. Intraoperative assessment demonstrated an intact rotator cuff in both shoulders, with no additional soft tissue injury. The greater tuberosity fracture of the right shoulder was fixed with a single cannulated screw and washer, whereas plate osteosynthesis was performed in the left shoulder due to the larger fragment size (Figure 2).OPEN IN VIEWER

Passive shoulder range-of-motion exercises were initiated on the first postoperative day as tolerated. During hospitalization, neurology consultation established a diagnosis of epilepsy, and medical treatment was initiated. Pendulum exercises were started at two weeks, followed by active shoulder exercises at six weeks. At discharge, the pain level had decreased to 2/10 on the VAS.

At two months postoperatively, shoulder range of motion had improved to 0–110° of abduction and 0–120° of flexion, with progressive gains in rotation. At four months, further improvement was observed, imaging confirmed fracture union without rotator cuff pathology (Figure 3), and the VAS score had improved to 0/10. At the one-year follow-up, no shoulder instability was detected, and the patient had returned to daily and sports activities without pain. At the final follow-up examination, bilateral shoulder range of motion was restored with forward flexion of 0°–170°, abduction of 0°–150°, and full internal and external rotation on both sides. The Constant–Murley score was 91 on the right and 89 on the left shoulder, indicating excellent functional outcomes.^19,20 Neurological follow-up continued, with no recurrent seizures reported.OPEN IN VIEWER

Discussion

This case is noteworthy in that it demonstrates that, in a patient with no prior diagnosis of epilepsy who presented to the emergency department with loss of consciousness, atraumatic bilateral anterior shoulder dislocation accompanied by bilateral greater tuberosity fractures may be attributable to underlying epilepsy despite the absence of a traumatic history. Favorable functional outcomes were achieved in the postoperative period through patient-specific surgical management and an appropriate multidisciplinary approach. In this respect, the present case emphasizes that severe muscle contractions during a seizure can result in significant extremity injuries even in the absence of trauma and highlights the importance of a thorough extremity examination and heightened clinical awareness of atypical presentations in patients presenting to the emergency department after a seizure.

Bilateral shoulder dislocation was first described in 1902 by Myenter in a case resulting from severe muscle contractions due to camphor overdose. ²¹ In subsequent years, a limited number of case reports associated with various etiological factors have been published.^4-6,8 Nevertheless, bilateral shoulder dislocations remain extremely rare, as their occurrence requires unusual biomechanical mechanisms. ⁵

In the literature, trauma is the most common cause of bilateral shoulder dislocations, accounting for approximately 50% of cases; described traumatic mechanisms include leverage, traction, and pushing forces.^4-6,8 The second most common cause is dislocation secondary to atraumatic muscle contractions, comprising approximately 37% of cases. Of these, nearly 33% are associated with epileptic, toxic, hypoglycemic, or hypoxic seizures, as well as muscle contractions resulting from electrical shock.^4-6,8

The majority of cases reported after seizures present as bilateral posterior glenohumeral dislocations. ⁶ However, a recent large-scale epidemiological study reported that atraumatically developed shoulder dislocations in individuals with epileptic seizures were distributed between anterior and posterior types at rates of 57% and 43%, respectively. ⁶ This finding indicates that epileptic seizures, although infrequently, may also result in bilateral anterior shoulder dislocation.

Some studies have suggested that anterior shoulder dislocation developing after a seizure may result not primarily from muscle contractions, but from secondary trauma caused by impact with the ground following collapse. ²² Loss of consciousness and impairment of protective reflexes during the postictal period may predispose patients to such secondary injuries. ²² However, in the present case, there was no history of falling or any traumatic impact during the seizure, and the injury is therefore considered to have developed directly as a result of seizure-related muscle contractions. In this respect, our case differs from the majority of cases reported in the literature.

In the present case, reduction was performed under operating room conditions, and radiography and computed tomography were repeated after reduction to reassess bone morphology and to exclude associated humeral neck fractures, particularly in the presence of the typical inferior displacement of the greater tuberosity.^23,24 In addition, the obtained CT images facilitated a more detailed assessment of both the fracture and the morphological and topographic characteristics of the glenohumeral joint, thereby aiding the treatment decision-making process. Magnetic resonance imaging was not performed because this was a first-time dislocation, with no evidence of significant soft tissue injury, instability, or an associated Hill–Sachs lesion. ²⁵

Because the greater tuberosity fragments were displaced by more than 10 mm and carried a risk of instability, surgical treatment was planned. Anticipating more stable fixation, a cannulated screw and washer were used for the right shoulder, whereas plate osteosynthesis was preferred for the left shoulder due to the larger fragment size. Although no well-defined algorithm exists in the literature for the management of greater tuberosity fractures, the indication for surgical treatment generally ranges from 3 to 10 mm of displacement.^3,26,27 Various surgical techniques have been described, including cannulated screws, arthroscopy-assisted suture anchor fixation, and plate osteosynthesis for larger fragments.^28,29 Therefore, the choice of treatment should be individualized based on fracture morphology and patient-specific factors.

This study has several limitations. First, as a single case report, the findings cannot be generalized, and no cause-and-effect relationship can be established. Second, electromyographic evaluation was not performed to objectively assess muscular activity during the seizure episode, which could have provided further insight into the injury mechanism. Third, although clinical and radiographic follow-up at one year demonstrated excellent functional outcomes, longer-term follow-up would be valuable to evaluate the durability of the surgical fixation, the potential for recurrent instability, and the long-term impact of epilepsy management on musculoskeletal health.

The coexistence of bilateral greater tuberosity fractures with atraumatic bilateral anterior shoulder dislocation secondary to an epileptic seizure represents an extremely rare clinical condition. Although a limited number of similar fracture–dislocation patterns have been previously reported in the English-language literature in association with seizures,^{5,7,8,12,13,15,16} to our knowledge the present case is among the very few in which bilateral greater tuberosity fractures accompanying atraumatic bilateral anterior shoulder dislocation led to the initial diagnosis of epilepsy in a previously healthy patient without any known neurological history. Because the greater tuberosity serves as the insertion site of the rotator cuff tendons, it requires a meticulous treatment approach from both morphological and functional perspectives.

Conclusion

Reporting such cases contributes to a better understanding of the underlying injury mechanisms and demonstrates that favorable functional outcomes can be achieved through appropriate surgical management and a multidisciplinary approach. Clinicians should maintain a high index of suspicion for seizure-related trauma in atraumatic bilateral shoulder injuries, pursue prompt neurological evaluation, and consider early surgical fixation for displaced fragments. Larger series are needed to define optimal management in epilepsy-related orthopaedic emergencies.