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MILITARY MEDICINE, 178, 3:e400, 2013

Simultaneous Bilateral Anterior Shoulder FractureDislocation Following a Seizure: A Case Report

LCDR Luke F. Bremner, MC USN*; CDR Christopher B. Dewing, MC USN†;LCDR Lucas S. McDonald, MC USN†; CDR Matthew T. Provencher, MC USN†

ABSTRACT Simultaneous, bilateral, anterior dislocations of the glenohumeral joint are rare, most attributable tomajor trauma. Seizure disorders and electrocution are a common cause of glenohumeral and fracture dislocationsalthough these are most commonly posterior injuries. We present an interesting case report of diagnosis and treatmentof an active duty sailor with bilateral anterior shoulder fracture dislocations following a seizure.

INTRODUCTIONAlthough unilateral dislocations of the shoulder are the most

frequently encountered dislocation seen in orthopedics, thebilateral variant is rare. When present, bilateral glenohumeral

dislocations more commonly occur in the posterior direction,usually secondary to violent muscle contraction in patients

experiencing seizures or electric shock. Simultaneous bilateral

anterior dislocations are extremely rare, with the majorityattributable to trauma. A review of the literature by Sharma

et al.1 yielded only approximately 30 cases with even fewer

cases of fracture dislocations. We report the case of a 28-year-old active duty sailor with bilateral anterior shoulder fracture

dislocations sustained during a first-time seizure episode.

CLINICAL CASEA 28-year-old active duty U.S. Navy male with a past medicalhistory significant only for hypertension presented to the

emergency department following a first-time, witnessed,tonic-clonic seizure while aboard his ship. The seizure was

attributed to an excessive dose of oral tramadol hydrochloride

combined with nortriptyline; a known reported cause of sei-zures. During evaluation in the emergency department, he

reported no recollection of the episode and denied any priorhistory of similar events. Internal medicine was consulted for

evaluation of his seizure. During their examination, the

patient complained of fatigue and diffuse cramping pain inhis neck, upper back, shoulders, and arms. Radiographic

evaluation included a computed tomography (CT) scan of hishead and cervical spine, both were normal. At the time of

admission, no shoulder images were obtained. The patient was

admitted to the internal medicine service for seizure workup.

By hospital day 2, the patient’s pain had localized to his

shoulders bilaterally. In light of his continued symptoms,

bilateral shoulder radiographs were obtained, showing bilat-

eral anterior-inferior glenohumeral fracture dislocations

(Figs. 1–4).

Orthopedics was consulted for evaluation and treatment.

The patient was neurovascularly intact, including normal

axillary nerve sensation, with both shoulders fixed in exten-

sion, abduction, and external rotation. In light of the time

elapsed since the injury, and given the fixed bilateral anterior

shoulder dislocations not amenable to gentle closed reduc-

tion, the patient was brought urgently to the main operating

room for conscious sedation and closed reduction. Successful

closed reductions were performed bilaterally utilizing a tech-

nique of longitudinal traction, external rotation, abduction,

and extension, combined with anterior pressure on the shoul-

der. Fluoroscopic imaging confirmed reduction and stability

through a functional arc of motion. The patient was initially

placed into sling and swathe immobilization bilaterally.

Post reduction, the patient was readmitted to the inpatient

ward and reported near resolution of his previous discomfort.

Anteroposterior radiographs confirmed maintenance of reduc-

tion. However, during positioning for the axillary lateral

view of the left shoulder, a recurrent dislocation occurred

with an immediate worsening of pain reported by the patient.

This was confirmed on the subsequent axillary view. The

patient was returned to the operating room for closed reduc-

tion of the left shoulder by the same technique and immobi-

lization in the most stable position of internal rotation using a

swath to maintain reduction. Plain radiographs were obtained

before application of immobilization ensuring reduction.

Subsequent CT imaging of both shoulders further character-

ize the fractures, showing bilateral displaced and commi-

nuted greater tuberosity fractures, with the presence of large

Hill–Sachs injuries, left greater than right (Figs. 5 and 6).

Given the recurrent left shoulder instability and associated

engaging Hill–Sachs lesion, the patient was brought elec-

tively to the operating room several days later for open

reduction and internal fixation of the left side.

*Department of Orthopedic Surgery, Naval Hospital Camp Pendleton,

Box 555191, Camp Pendleton, CA 92055.

†Department of Orthopedic Surgery, Naval Medical Center San Diego,

34800 Bob Wilson Drive, Suite 112, San Diego, CA 92134.

Dr. Provencher or an immediate family member serves as a board mem-

ber, owner, officer, or committee member of the American Orthopaedic

Society for Sports Medicine, Arthroscopy Association of North America,

American Academy of Orthopaedic Surgeons, and Society of Military

Orthopaedic Surgeons.

The views expressed in this exhibit are those of the authors and do not

reflect the official policy or position of the Department of the Navy, the

Department of Defense, or the U.S. Government.

doi: 10.7205/MILMED-D-12-00378

MILITARY MEDICINE, Vol. 178, March 2013e400

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A modified transverse U-type incision was utilized to

access the shoulder joint, reflecting the posterior deltoid

before entering the joint capsule. The greater tuberosity frac-

ture was in two large, yet comminuted pieces representing

the footprints of the supraspinatus and infraspinatus tendons

with a Hill–Sachs lesion that composed 35% of the posterior

humeral head and engaged the glenoid resulting in dislocation

with physiologic motion. The supraspinatus and infraspinatus

rotator cuff tendons were avulsed off the bone fragments and

were incompetent. Because of the large Hill–Sachs and impac-

tion injuries, a combination of frozen allograft humeral head,

cancellous allograft chips, osteoinductive putty, and autograft

cancellous bone was utilized for restoration of bone stock

and subsequent rotator ruff repair (Figs. 7–9). The shoulder

was then examined through a range of motion under fluoros-

copy confirming reduction and anatomic osseous restoration

(Fig. 10). The deltoid was repaired to the acromion through

bone tunnels, and a layered closure was performed.

Postoperatively, sling immobilization was employed for

6 weeks with immediate restricted passive motion transitioning

to with active-assisted exercises at 6 weeks, formal strength-

ening at 12 weeks, and return to full activity at 6 months

following radiographic and clinical healing (Fig. 11). He later

required an arthroscopic subacromial bursectomy, with a mini

open hardware removal for prominent screws causing

impingement symptoms. The contralateral right shoulder

was treated nonoperatively because he maintained a stable,

concentric, and well-functioning shoulder following a compre-

hensive physical therapy program. At 18 months postinjury,

FIGURE 1. Anteroposterior radiograph of the right shoulder showinga glenohumeral dislocation with a greater tuberosity fracture.

FIGURE 2. Axillary view of the right shoulder showing an anteriorlydislocated glenohumeral joint. This view is necessary to determine thedirection of the dislocation.

FIGURE 3. Anteroposterior radiograph of the left shoulder showing aglenohumeral dislocation with a greater tuberosity fracture.

FIGURE 4. Axillary view of the left shoulder showing an anteriorlydislocated glenohumeral joint. This view is necessary to determine thedirection of the dislocation.

MILITARY MEDICINE, Vol. 178, March 2013 e401

Case Report

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both shoulders showed full flexion, abduction, abducted

external rotation, and abducted internal rotation without insta-

bility findings.

DISCUSSIONSimultaneous bilateral anterior shoulder dislocations are a

rare entity, with fracture dislocations even more uncom-

mon.1–4 The simultaneous bilateral posterior variant, first

described over 100 years ago, is more commonly described.

A comprehensive search of the literature produces few cases

of simultaneous bilateral anterior fracture dislocations caused

by a seizure.4–6 The unique aspects of this case are the

simultaneous anterior dislocations, causing bilateral greater

tuberosity fractures (left greater than right), with one side

FIGURE 5. Axial cut of left shoulder CT scan showing a greater tuberos-ity fracture.

FIGURE 6. Coronal slice of the left shoulder CT showing a comminutedtuberosity fracture.

FIGURE 7. Osteochondral allograft shaped from humeral head allograft.

FIGURE 8. Final fixation of the osteochondral allograft with 2.7-mmscrews washers in a bicortical lag technique through the greater andlesser tuberosities.

FIGURE 9. Rotator cuff repair with Mason-Allen suture configurationand knotless anchor fixation.

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requiring operative intervention for a displaced greater tuber-

osity and multiple recurrent dislocations. The cause of his

seizure activity was attributed to the combination of tramadol

hydrochloride and nortriptyline, lowering the seizure thresh-

old, a known side effect of this medication. Since his initial

hospitalization, he has experienced no additional seizure

activity and has been seizure-free since this initial episode at

age 28.

Typically, in the setting of a seizure, the weak external

rotators are overwhelmed by the internal rotators, causing

an exaggerated adduction and internal rotation, resulting in

posterior dislocation.7 Anterior dislocations are more com-

monly the result of trauma, with positioning of the shoulder

in extension, abduction, and external rotation during a fall.

The resultant impingement of the greater tuberosity on the

acromion causes the dislocation. They are typically unilateral

as one extremity usually takes the brunt of the force. It is in

only about 15% of anterior dislocations that a displaced frac-

ture of the tuberosity occurs. A displaced greater tuberosity

fracture almost certainly represents an incompetent rotator

cuff, and long-term instability and disability can ensue.8 This

patient had instability because of the fracture pattern and

injuries, necessitating an open reduction and fixation with

allograft augmentation to provide stability. An increased risk

of fracture with glenohumeral dislocations is noted to occur

in the setting of advanced age, first time dislocations, and

high-energy mechanisms.9 The combination of these factors

makes bilateral anterior shoulder fracture dislocations rare.

In this case of a young patient with a low energy mechanism,

the severity of the greater tuberosity fracture is quite impres-

sive. It is not known why some dislocations occur anteriorly

during seizure activity, since the majority of shoulder dislo-

cations associated with seizures are posterior, though, may

be due to the position of the shoulders during the seizure.

Whether the dislocation occurs anterior or posterior, the

same initial management principles apply—early reduction

and immobilization. Early fixation of this patient’s left

shoulder was performed in the setting of recurrent instability

showing early failure of nonoperative management.

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literature. Int Orthop 1999; 23: 128–30.

3. Nagi ON, Dhillon MS: Bilateral anterior fracture dislocation of the

shoulders. J Orthop Trauma 1990; 4: 93–5.

4. Ribbans WJ: Bilateral anterior dislocation of the shoulder following a

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5. Segal D, Yablon IG, Lynch JJ, Jones RP: Acute bilateral anterior disloca-

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7. Mynter H: XIV. Subacromial Dislocation from Muscular Spasm. Ann

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9. Emond M, Le Sage N, Lavoie A, Rochette L: Clinical factors predicting

fractures associated with an anterior shoulder dislocation. Acad Emerg

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FIGURE 11. Coronal slice of the left shoulder CT showing a healedosteochondral allograft fixation.

FIGURE 10. Immediate postoperative anteroposterior left shoulder radio-graph showing final fracture fixation construct. The apparent shoulderpseudosubluxation is expected immediately postoperatively despite a stableand reduced glenohumeral joint.

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