Posterior SternoclavicularJoint Injury in the Pediatric

PatientAndrew Schapiro MD, Jie Nguyen MD, MS, Michael Kim MD, Kara Gill MD

University of Wisconsin Hospital and Clinicsaschapiro@uwhealth.org

Disclosures

The authors have no disclosures

Purpose

Review the anatomy of the sternoclavicular

(SC) joint and mechanisms of injury

Review the clinical presentation and

possible complications of posterior SC

injury

Consider the use of various imaging

modalities in imaging assessment

Describe methods of treatment

Posterior Sternoclavicular Injury

Two types in children and young adults:– Medial clavicle physeal fracture with posteriorly displaced clavicular metaphysis

• Most common injury until physeal fusion

• Salter-Harris I or II

– True posterior/retrosternal SC joint dislocation

Epidemiology:– Rare

• Ratio of anterior to posterior SC injury – 2.5:1 to 20:1

• Only 1 case of posterior injury in a large series of 1603 shoulder girdle injuries

• <1% of dislocations in the body

Significance– Often easily overlooked on clinical and imaging assessment

– Acute and delayed complications can occur if unrecognized and untreated

– Can be lethal

Anatomy

Clavicle– 1st long bone to ossify - 5 weeks GA

– Last epiphysis to fuse - 21-31 years old

Sternoclavicular

joint– Overlies the upper mediastinum - great

vessels, trachea, esophagus

– Only true articulation between the upper

extremity and axial skeleton

– Diarthrodial, saddle shaped joint

– Most unstable major joint in the body -

<50% of the medial clavicle articulates

with the manubrium

– Ligaments provide joint stability

Figure 1: Axial cadaver section demonstrating the proximity of

the SC joints to the upper mediastinal structures. Clavicle (C),

sternum (S), right subclavian vein (RSV), right innominate artery

(RIA), left carotid artery (LCA), left subclavian vein (LSV), left

subclavian artery (LSA), trachea (Tr), esophagus (E)

(Levinsohn EM. Clin Orthop Relat Res 1979;140:12-16)

Anatomy SC (capsular) ligaments

– Thickenings of the anterior and posterior joint capsule

– Major stabilizers of the SC joint

– Posterior is thicker/stronger – may partially account

for increased rate of anterior dislocation

Coracoclavicular ligament– Extends from the medial first rib to the medial clavicle

– Opposes the pull of the sternocleidomastoid muscle

on the clavicle

Interclavicular ligament– Connects the superomedial aspect of the clavicles with the capsule and upper sternum

– Helps prevent lateral displacement of the clavicle

Intra-articular disk ligament– Arises from the synchondral junction of the 1st rib and sternum and divides the SC joint into two

– Helps prevent medial displacement of the clavicle

Figure 2: Illustration of the basic anatomy of the

SC joint. (Nettles JL. J Trauma 1968;8:158-64)

Mechanism

Cause of injury– MVA - most common cause (40%)

– Sports injury - second most common cause (21%)

– Falls, industrial accidents, miscellaneous trauma (39%)

– Rarely can be spontaneous

Mechanism of injury– Indirect

• Force to the posterolateral shoulder

• Clavicle levers on the first rib, transmitting a posterior force to the medial clavicle

• Most common mechanism of injury

– Direct

• Force to the anteromedial aspect of the clavicle

• Less common mechanism of injury - 1 in 4 to 1 in 9 cases

Clinical Presentation Signs and symptoms of injury

– Pain localized to the SC joint, clavicle, and/or shoulder

– Tenderness over the SC joint

– Ipsilateral arm flexed at the elbow and supported across the chest by the other arm

– Head tilt toward the ipsilateral side

– Depression of the medial clavicle and/or swelling over the clavicle

– Decreased range of motion due to pain

Signs of secondary effect on the

mediastinum– Dysphagia

– Dyspnea

– Dysphonia

– Upper extremity weakness and/or paresthesia

– Neck and upper extremity venous congestion

– Decreased upper extremity pulse

– Hypotension/shock

Figure 3: Signs of posterior SC injury.

(Worman LW. J Trauma1967;7:416-23)

Figure 4: 15 year old male who sustained a direct

force to the anterior upper right chest during

wrestling. (a) Photo obtained during physical

exam demonstrates depression of the medial right

clavicle. (b) AP clavicle radiograph showing subtle

superior displacement of the right clavicular head

relative to the left. (c) CT chest without contrast

showing a posteriorly displaced right clavicle

Salter-Harris fracture with a tiny fracture fragment

(arrow) anterior to the medial right clavicle.

a b

c

Complications

Mediastinal complications in ~25% of

patients

Acute– Great vessels – compression, laceration

– Trachea – compression, tracheoesophageal fistula

– Esophagus – compression, rupture

– Lungs – pulmonary contusion, pneumothorax, hemothorax

– Brachial plexus or recurrent laryngeal nerve injury

Chronic– SC joint instability and/or osteoarthritis

– Arterial stenosis or pseudoaneurysm

– Venous congestion

– Thoracic outlet syndrome

Radiography

AP view• May show asymmetry of the medial clavicles

• Posterior SC injury is often occult

Additional views• Serendipity – patient supine, 40 degree cranial tilt of the X-ray tube

• Hobbs – patient seated leaning over table, tube aimed downward toward the C-spine

• Heinig – patient supine, tube lateral to the patient tangential to one SC joint and parallel to

the other, often images of both sides are obtained for comparison

Figure 5: (a) Serendipity view (b) Hobbs view

(Cope R. Skeletal Radiol 1993;22:233-8)

Figure 6: Heinig view

(Lee FA. Radiology 1974;110:631-4)

a

b

Obtaining an AP view and at least one

additional view (typically serendipity at our

institution) is recommended to increase

sensitivity for detection

Figure 7: 14 year old male who fell onto his right shoulder during snowboarding. (a) AP view of the bilateral clavicles

showing minimal inferior displacement of the medial right clavicle relative to the left. (b) Serendipity view much better

demonstrating this inferior displacement.

a

b

Figure 8: 17 year old male who sustained an impact to the lateral left shoulder during a hockey game. (a) AP view of

the left clavicle showing superior displacement of the left clavicle relative to the right. (b) Serendipity view of the left

clavicle on which the clavicular displacement is occult.

a

b

CT

CT for SC dislocation first described in 1979

Advantages– Widely available and readily accessible in the acute setting

– Can identify SC dislocation that is occult on radiographs, or confirm a radiographic diagnosis

– If the epiphysis is at least partially ossified CT may help differentiate a medial clavicle Salter-

Harris fracture from true SC dislocation, which may impact management

– Can be used to assess the vasculature if contrast is administered

– Can identify evidence of injury to other structures including the esophagus and trachea

– Intra-operative cone beam CT can be used to confirm the success of reduction

Disadvantages– Ionizing radiation - limited coverage of just the SC joints minimizes radiation exposure

– If contrast is administered there is a small risk of reaction and/or nephrotoxicity

Even if radiographs appear normal CT

should be obtained if high clinical

suspicion remains

Use of IV contrast is recommended to

assess the vasculature prior to reduction

Figure 9: 17 year old male who sustained a lateral impact to the left shoulder during a hockey game. (a) CT without contrast

shows posterior displacement of the left medial clavicular metaphysis with the epiphysis seen anteriorly (arrow), compatible

with displaced Salter-Harris fracture. (b) Intra-operative cone beam CT showing successful reduction of the fracture.

a b

Figure 10: 13 year old male thrown onto his right

shoulder during wrestling. (a) CT chest with contrast

on bone window showing posterior right SC

dislocation. (b) Same CT image on soft tissue window

showing mass effect from the posteriorly dislocated

clavicle on the distal left brachiocephalic vein (arrow).

a

b

MRI

Advantages– No ionizing radiation

– Excellent soft tissue contrast resolution

– Osseous structures and unossified cartilage can be identified

– Contrast can be administered to assess the vasculature

• Low rate of contrast reaction

• Low theoretical risk of nephrotoxicity

• Newer contrast agents with a longer blood pool half-life (i.e. gadofosveset trisodium) may

help optimize vascular assessment by allowing for extended vascular imaging

– Patients with SC injury are typically teenagers who can remain still for MRI without sedation

Disadvantages– Not always readily available in the acute setting

– Difficulty monitoring the unstable patient (i.e. trauma patient with polyinjury)

– More expensive than routine CT

MRI may play a more prominent role in the

imaging of sternoclavicular joint injury in the

future given its ability to simultaneously

evaluate the bones, cartilage, soft tissue

structures, and the vasculature without the

use of ionizing radiation

Figure 11: 16 year old male

involved in a motorcycle accident

who presented with right clavicle

pain. The patient had multiple

distracting injuries and posterior

SC injury was missed on initial

radiographs. (a) MRI/MRA chest

showing posterior displacement

of the medial right clavicle (solid

arrow). Surrounding soft tissue

edema and anterior callus

formation (open arrow) are

present. (b) CT without contrast

showing the posterior dislocation

and early callus formation.

a

b

Figure 12: 17 year old female who fell

and landed on her right shoulder during

a soccer game. Initial radiographs

obtained at an outside hospital were

interpreted as negative. The patient

presented 3.5 weeks later with

persistent medial right clavicle pain. (a)

CT without contrast showing posterior

dislocation of the right clavicular head

with anterior callus formation (arrow).

(b) MRI/MRA following repair showing

improved alignment and post-surgical

change.

a

b

Ultrasound (US)

Reports of US use for posterior SC injury– Intra-operative assessment of closed reduction success

– Diagnosis of closed reduction failure at clinic follow-up

Advantages– No ionizing radiation

– Real-time assessment in any imaging plane

– Portable, with potential for use in the emergency department, operating room, or clinic.

Disadvantages– Mediastinal structures cannot be assessed

– Limited expertise for this indication

– Limited literature on the use of this modality for this indication

Figure 13: (a) Side by side US images of the right

(arrowhead) and left (solid arrow) medial clavicles in a

patient with a posterior dislocation of the left SC joint. (b)

Extended field of view US image demonstrating the

relative positions of the right and left clavicular heads.

The periosteal sleeve is seen anterior to the left clavicle

(open arrows). Sternum (S). (Delganelo A. Skeletal Radiol

2012;41:857-60)

Management Controversial

Closed reduction– Many advocate attempt at closed reduction if performed within 48 hours of injury

– Successful closed reduction up to 10 days after injury has been described

– Reported success ~40-60% in several adult series

– Sedation or general anesthesia typically administered

– Thoracic surgery should be on standby or in the operating room

– Open reduction performed right away if unsuccessful

Open reduction– Some advocate open reduction as first line therapy in pediatric patients due to the high rate of

physeal fracture in this population and reported poor success of closed reduction in this setting

– Many different methods

• Internal fixation with plates, pins, wire – no longer recommended due to reports of multiple

fatalities related to hardware migration

• Tendon grafts

• Suture fixation – performed at our institution

• Medial clavicle resection – not recommended in pediatric patients

– Thoracic surgery should be on standby or in the operating room

Figure 14 (left): Illustration of a commonly used closed

reduction technique (the technique typically used at our

institution). The patient is laid supine with a several centimeter

thick sandbag between the scapulae. The ipsilateral arm is

abducted and extended and traction is applied. The medial end

of the clavicle may be grasped and pulled anteriorly with

fingers or a towel clamp. (Salvatore JE. Clin Orthop Relat Res

1968;58:51-5)

Figure 15 (right): Intra-operative photo showing

suture fixation of a clavicle Salter-Harris fracture

with nonabsorbable suture. Clavicle (C), sternum

(S).

(Waters PM. J Pediatr Orthop 2003;23:464-9)

C

S

Summary

Posterior SC injury is rare but associated

with many complications

It is often missed on initial radiographs– Obtain at least 2 views

– Always assess medial clavicular alignment

Obtain CT with contrast or MRI/MRA if

there is high clinical suspicion regardless of

radiographic findings– Can identify or confirm the diagnosis

– Can evaluate for associated vascular or soft tissue injuries

Prompt diagnosis can impact management

and reduce morbidity

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