CASE REPORT scapula, dislocation

Scapular Dislocation (Locked Scapula)

We report the case of a 19-year-old woman who presented to the emergency department with pain and inability to move her right shoulder after fall- ing backwards and striking it on a cart. Radiographs of the shoulder re- vealed a dislocated scapula. Closed reduction in the ED was successful. This rare case of scapular dislocation serves to emphasize that a height- ened awareness for this injury is necessary if it is to be recognized and treated appropriately. Its treatment and prognosis are reviewed. [Walker JS, Walker BB: Scapular dislocation (locked scapula). Ann Emerg Med No- vember i990;I9:1329-138i.]

INTRODUCTION Although pat ients wi th shoulder injuries commonly present to the

emergency department for evaluation, those with dislocation of the scap- ula are only rarely encounteredJ -3 Scapular dislocation (locked scapula, scapulothoracic dislocation, scapulothoracic dissociation) may occur as an isolated injury, or more commonly in the multiple trauma patient. 2-s Be- cause of its infrequent occurrence and the possible existence of more life- threatening injuries, its recognition is often delayed or missedA

A heightened awareness for this injury is necessary if it is to be recog- nized and treated in a timely manner. Prompt recognition and treatment can usually be achieved by closed reduction, whereas delayed recognition may require open reduction.

We report the case of a young woman with a scapular dislocation after a minor fall.

CASE REPORT A 19-year-old woman in previously good health presented to the ED with

pain and inability to move her right shoulder after a fall. Two hours prior to presentation, she was standing on her toes cleaning a tall set of shelves when she fell backwards and struck her right shoulder on a cleaning cart. She experienced the onset of severe pain in her right shoulder, extreme difficulty in moving her right arm and shoulder, and numbness and tin- gling in the right arm. She offered no other complaints.

Physical examination of her right shoulder revealed an obvious defor- mi ty consisting of a protruding axillary border of the scapula and massive soft tissue swelling over the vertebral border of the scapula. The patient would not move her right upper extremity due to the severe pain. Palpa- tion of the scapula elicited severe pain. The right brachial, radial, and ulnar pulses were palpable. Neurological examination revealed a subjective sen- sory deficit of the lower right arm. No motor deficits were appreciated.

Radiographs of the shoulder (Figures 1, 2, 3, and 4) were obtained and revealed a dislocation of the scapula. The internal rotation and external rotation anteroposterior (AP) views demonstrated lateral displacement of the scapula (Figures 1 and 2). The anterior oblique view displayed the intra- thoracic position of the scapula (Figures 3 and 4). There were no associated fractures of the scapula or humerus.

Orthopedic consultation was obtained. Closed reduction was accom- plished without difficulty or redislocation. No vascular lesions were found. A subjective paresthesia was present consistent with a neuropraxia of the brachial plexus. No motor deficits were found. No acromioclavicular inju-

James S Walker, DO Oklahoma City, Oklahoma Beth B Walker, DO Broken Arrow, Oklahoma

From the Section of Emergency Medicine and Trauma, Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City; and the Department of Emergency Medicine, Broken Arrow Medical Center, Broken Arrow, Oklahoma.

Received for publication February 28, 1990. Accepted for publication May 8, 1990.

Address for reprints: James S Walker, DO, Section of Emergency Medicine and Trauma, University of Oklahoma Health Sciences Center, PO Box 26307, Room EB 319, Oklahoma City, Oklahoma 73126.

19:11 November 1990 Annals of Emergency Medicine 1329/147

SCAPULAR DISLOCATION Walker & Walker

FIGURE 1. External rotation AP view of the shoulder revealing lateral dis- placement of the scapula.

FIGURE 2. Internal rotation AP view of the shoulder revealing lateral dis- placement of the scapula.

FIGURE 3. Anterior oblique view of the shoulder demonstrating intra- thoracic positioning of the scapula.

ries were found. A sling and a swathe were applied to the patient’s right arm after the scapula was displaced medially and taped in place. On re- evaluation the next day, the patient noted a marked improvement in pain and resolution of the subjective sen- sory deficit. The patient recovered fully in four weeks.

DISCUSSION Scapular dislocation is a relatively

uncommon injury.l-3 To our ltnowl- edge, there have been only eight doc- umented references describing or re- porting this injury.l-s This injury is rare because the vector of force must tear, rupture, or severely strain the musculature surrounding the scap- ula, notably the rhomboid muscles attached to the vertebral border. The entire body of the scapula is dis- placed forward and laterally with the inferior angle being wedged between the posterolateral ribs.l-3

14an330 Annals of Emergency Medicine 19:il November 1990

Two m e c h a n i s m s of i n ju ry have been proposed to explain the occur- rence of th i s les ion . T h e f i rs t pro- posed mechan i sm is the forceful out- ward t rac t ion applied to the arm. The second proposed mechan i sm is a di- rect b low to the poster ior surface of the scapula, dr iv ing i t forward and lateral. 1-3 It is apparent that such a vector of force capable of dis locat ing a scapula m a y also cause fractures as wel l as severe neurovascular injuries.

Major t r auma to the shoulder gir- dle can be l i fe- threatening due to in- juries, sus ta ined to the vascula ture of the thoracic out le t and axilla.6, 7 Ac- cordingly, once a scapular d is locat ion is recognized, a thorough evaluat ion s h o u l d be c o n d u c t e d for b r a c h i a l p lexus injur ies ; in jur ies to the sub- clavian ar tery and vein; and fractures to the ribs, clavicle, scapula, and hu- merus.6, 7 Conver se ly , the s capu la r d i s l o c a t i o n per se m a y no t be in i - t ia l ly recognized due to the presence of mu l t ip l e or other l i fe- threatening injuries, one of which m a y be the hy- po tens ion associated w i th the subcla- v ian vascu la r injury. 1-3 In addi t ion , one case of n o n t r a u m a t i c s capu la r dis locat ions was repor ted in a pat ient

who had an en bloc r e sec t ion of a Pancoast tumor. 8

R o u t i n e AP r a d i o g r a p h s of t h e chest or shoulder wil l depict lateral d i sp lacement of the scapula. Anter ior o b l i q u e v i e w s w i l l r e v e a l i n t r a - thorac ic pos i t ion ing of the scapula. Tangent ia l or t ransscapular views of the shoulder also wi l l i l lus t ra te ab- normal pos i t ioning of the scapula.l-3

Closed reduct ion of the dis located scapula cons is t s of t r ac t ion on the hyperabdueted arm as the scapula is in terna l ly rota ted by pushing on i ts axi l lary border. More specifically, an ass is tant applies s teady longi tudinal t r ac t ion on the hype rabduc ted arm, whi le the axi l lary border of the scap- ula is grasped and is rota ted forward and pushed media l ly . Closed reduc- t ion is usual ly successful in rapidly recognized dislocations. Open reduc- t ion is c o m m o n l y required if the di- agnosis is delayed. 1

A f t e r r e d u c t i o n , t h e s c a p u l a is f ixed to the pos te r ior thorac ic wa l l w i t h s t r i p s of a d h e s i v e t a p e . A swa the is appl ied a round the ches t and arm; the arm is supported wi th a cuff sling and a collar. This means of i m m o b i l i z a t i o n is e i ther re inforced

F I G U R E 4. M a g n i f i e d a n t e r i o r ob l ique v i e w of the scapula empha- s i z ing t h e in t ra thorac ic p o s i t i o n i n g of the scapuIa.

or changed in seven to ten clays and removed after two more weeks. ~

SUMMARY Disloca t ion of the scapula is rare.

A high index of suspicion should be ma in t a ined for this injury whenever t h e p a t i e n t h a s s u s t a i n e d b l u n t t rauma to the thorax or shoulder and radiographs d e m o n s t r a t e la te ra l dis- p l acemen t of the scapula. Significant neurovascu la r in jur ies m a y also be present.

In the mul t ip le t r auma patient , i t s recogni t ion is often delayed because of the c o e x i s t e n c e of m o r e se r ious in jur ies . However , the sooner i t is recognized, the bet ter the chance of c lo sed r e d u c t i o n and a good o u t - come. In the pa t ien t wi th a scapular d is locat ion as an isolated injury, the in jury is more eas i ly d iagnosed and may be reduced wi th good success in the ED.

REFERENCES 1. Depalma AF: Fractures and dislocations of the scapula, in Surgery of the Shoulder, ed 3. New York, JB Lippincott, 1983, p 371. 2, Conwell HE, Reynolds F: Diagnosis and treatment of specific injuries in Key JA, Crom- well HE (eds): Management of Fractures, Dis- locations, and Strains, ed 7. St Louis, CV Mosby, 1961, p 388. 3. Rockwood CA: Dislocation about the shoul- der, in Rockwood CA, Green DP (eds): Fractures in Adults, ed 2. New York, JB Lippincott, 1984, p 948. 4. Nettrour LF, Krufky EL, Mueller RE, et ah Locked scapula: Intrathoracic dislocation of the inferior angle. J Bone Joint Surg 1972;54-A: 413~416. 5. Hollinshead R, James KW: Scapulothoracic dislocation (locked scapula). J Bone Joint Surg 1979;61-A:1102 1103. 6. Oreck SL, Burgress A, Levine AM: Traumatic lateral displacement of the scapula: A radio- graphic sign of neurovascular disruption. J Bone Joint Surg 1984;66-A:758-763. 7. Rebenstein JD, Ebraheim NA, Kellam JF: Traumatic scapu|othoracic dissociation. Radiol- ogy 1985;157:297-298. 8. Ward WG, Weaver JP, Garrett WE, Jr: Locked scapula. J Bone Joir~t Surgery 1989;71-A: 1558 1559.

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