Download E2413 - Trauma of the Clavicle

Claire K Sandstrom1, Stephen A Kennedy2, Joel A Gross1
University of Washington School of Medicine – Harborview Medical Center
1 Department of Radiology, Section of Emergency & Trauma Radiology
2 Department of Orthopaedics & Sports Medicine
ARRS 2015
Toronto, Canada

No relevant financial disclosures for any of the authors
After reviewing this educational exhibit, you will be able to:

Describe the surgical considerations for:
◦ Clavicle fractures, depending on location (lateral, middle, medial)
◦ Acromioclavicular joint separation
◦ Sternoclavicular joint dislocation

Recognize imaging signs of clinically significant injuries:
◦ Complex shoulder injury – Floating Shoulder
◦ Complex shoulder girdle injury – Scapulothoracic Dissociation

Target Audience: Emergency and Musculoskeletal Radiologists, including
physicians-in-training

The clavicle is the sole osseous linkage between the torso and upper extremity, via
its sternoclavicular and acromioclavicular articulations

The clavicle shape varies between patients but is generally S-shaped
S-shaped clavicle as seen from above on 3D
volume rendered reconstruction
Muscular attachments of the clavicle and direction of muscular
tension (white arrows on lateral clavicle; black arrows on medial
clavicle). SCM = sternocleidomastoid
acromion
SCM
acromioclavicular
joint
humerus
head
shaft
trapezius
deltoid
pectoralis
major
sternoclavicular
joint
manubrium

Unlike other bones, true orthogonal XR projections of the clavicle are not achievable

Clavicle radiographic evaluation includes a horizontal AP XR and an apical oblique
XR with 15-40o (usually 25-30o) of cephalic angulation
superior
1. Sternoclavicular joint
3
1
Radiographic Anatomy
6
2
(SCJ)
4
2. Clavicular head
AP Clavicle XR
inferior
5
1
2
anterosuperior
3
6
4. Conoid tubercle
5. Deltoid tubercle
6. Acromioclavicular joint
(ACJ)
4
Apical Oblique Clavicle XR
3. Shaft
posteroinferior

Dedicated evaluation of the ACJ includes the bilateral joints in upright position
simultaneously

“Stress views” can also be obtained with weights in each hand

Stress views may be helpful in confirming the diagnosis of an AC separation when
the diagnosis is unclear from the physical examination or to confirm a type III
dislocation when surgery is being considered, but are uncomfortable for the patient
and may not change management, so are not routinely performed

Abnormal alignment may actually improve on the stress views due to active muscular
contraction. Regardless of when it is seen, abnormal alignment confirms injury

Other specialized views of the clavicle include:
◦ Zanca view
• 10-15o cephalic inclination @ ⅓–½ kVp of normal shoulder XR for visualization
of the ACJ and distal clavicle
• This view is not usually needed or obtained in the ED setting
Zanca Clavicle XR
AP Clavicle XR
◦ Serendipity view
• 40o cephalic inclination for visualization of the SCJ and medial clavicle. This
region is better seen on CT
Serendipity Clavicle XR
AP Clavicle XR

Although other classification systems exist, the Allman system1 is used most
frequently and divides the clavicle into thirds. Fracture frequency, demographics, and
complications differ by location
15-20% of clavicle
fractures2,3
GROUP II
Lateral
GROUP III rare – <5%2,3
Medial usually heal well
most likely to
displace and go on
to nonunion
(Distal)
(Proximal) most common in
elderly
osteoporotic
population2
GROUP I
Mid Shaft
most common in
elderly osteoporotic
adults2
(Middle)
most common location of clavicle
fracture - 75-80%2,3
most common in children and young
adults2

We will discuss each of these fracture groups separately
1.
2.
3.
Allman FL. J Bone Joint Surg Am. 1967;49:774-84
Nordqvist A, Petersson C. Clin Orthop Relat Res 1994; 300:127-32
O'Neill BJ, et al. Int Orthop 2011; 35:909-14
GROUP I

Traditionally treated conservatively

More recent reports describe 15-20% rate
of nonunion and impaired upper limb
function when certain fractures are
treated non-operatively1-6

A 2007 multicenter RCT2 of completely
displaced fractures without osseous
contact showed operative fixation:
◦ rates of nonunion thought to be ~1%
Exceptions requiring immediate surgery

•
open fractures
•
compromised “tented” skin (Fig below)
•
vascular or neurologic injury
◦ improved functional and symptomatic scores
compared with closed reduction
However, there is a trend toward
primary repair of more clavicle
fractures
◦ reduced time to union and rate of nonunion
◦ decreased malunion
24yo man with mildly comminuted, displaced
mid clavicular shaft fx with skin tenting (arrow)
◦ increased patient satisfaction with
appearance of shoulder
Apical Oblique Clavicle XR
1.
2.
3.
4.
5.
6.
McKee MD, Wild LM, Schemitsch EH. JBJS 2003; 85A:790-797.
Canadian Orthopaedic Trauma Society. JBJS 2007; 89A:1-10
McKee MD, et al. JBJS 2006; 88A:35-40
Zlowodzki M, et al. J Orthop Trauma 2005; 19:504-7
Virtanen KJ, et al. Acta Orthop 2012; 83:65-73
Hill JM, et al. JBJS 1997; 79B:537-539
GROUP I
Fractures for which internal fixation
may now be considered:
◦ completely displaced fractures
◦ initial clavicular shortening ≥ 2 cm
◦ comminuted z-shaped fracture
What is a “completely displaced fracture”?
◦ translation of one full clavicular shaft
width (100%) – superior, anterior, etc.
 i.e. inferior cortical edge of the medial
fragment is superior to the superior cortical
edge of the lateral fragment (fig below)
◦ no osseous contact
46yo man with bilateral clavicular midshaft fractures.
Right AP Clavicle XR
Left AP Clavicle XR
The right fracture is completely displaced – the medial inferior
cortex (black arrow) is displaced above the superior cortex
(white arrow) of the lateral fragment. This underwent surgical
fixation (below)
Post-op AP Clavicle XR
The left fracture was mildly displaced – the medial inferior
cortex (black arrow) is still below the superior cortex (white
arrow) of the lateral fragment. This was treated conservatively
GROUP I
Fractures for which internal fixation
may now be considered:
How is “clavicular shortening” measured?
◦ completely displaced fractures
◦ difficult for both radiologists and orthopedic
surgeons, and interrater reliability is poor1,2
◦ initial clavicular shortening ≥ 2 cm
Options include:
◦ comminuted z-shaped fracture
◦ unilateral view measuring amount of osseous
overlap (Fig to left)3
AP Clavicle XR
◦ symmetric bilateral views measuring clavicle
length difference (Fig below)
◦ 3D CT (but unnecessary radiation and expense
in most cases)
◦ clinically with measuring tape (on skin)
2 cm
34yo man with borderline shortening when
measuring the amount of osseous overlap.
The distance between the superior cortices
of the medial (white arrow) and lateral (black
arrow) bone fragments is approximated
(double-ended yellow arrow).
After
discussion, the patient underwent ORIF.
1.
2.
3.
Jones GL, et al. Am J Sports Med 2014; 42:1176-81
Silva SR, et al. J Pediatr Orthop 2013; 33:e19-e22
Hill JM, McGuire MH, Crosby LA. JBJS 1997; 79B:537-9
15yo boy with 3 cm of left shortening when comparing length of bilateral clavicles
Bilateral Upright Clavicle XR
GROUP I
Fractures for which internal fixation
may now be considered:
◦ completely displaced fractures
◦ initial clavicular shortening ≥ 2 cm
What is a “z-shaped fracture”?
◦ Segmental fracture of the middle third
with the segmental fragment rotated
vertically
◦ comminuted z-shaped fracture
43yo man with more displaced and comminuted z-shaped
clavicle fracture, which was repaired with cortical plate
16yo man with z-shaped clavicle fracture, which was
repaired with cortical plate
AP Clavicle XR
AP Clavicle XR
Post-op AP Clavicle XR
Post-op AP Clavicle XR
GROUP II

What is the “lateral clavicle”? Several different definitions exist in the literature:
◦ Fractures occurring lateral to both components of coracoclavicular ligament (CCL)
◦ Fractures of the lateral ⅓ of the clavicle
◦ Fractures of the lateral ⅕ of the clavicle - lateral to a vertical line from middle of
corocoid base (usually marked by conoid tuberosity)
Is this a lateral clavicle fracture?
AP Clavicle XR
If you use the 1st or 3rd definitions
above (lateral to CCL or lateral ⅕),
then the answer is no
However, it does involve the lateral
third – we will therefore describe
this as a lateral clavicle fracture

For this discussion, we will use the most common definition, which is the lateral 1/3,
encompassing the bone just medial to the CCL

Lateral clavicular fractures are less common than midshaft fractures

However, lateral fractures are associated with higher rate of nonunion than with
midshaft fractures, likely due to associated ligamentous injuries. The risk of nonunion
is greatest when the fracture has no osseous contact and with advancing age1
1.
Robinson CM, et al. JBJS 2004; 86A:1359-65
GROUP II

Most fractures (75%) are between the CCL and ACJ, and the ligaments remain intact;
these fractures can be treated nonoperatively
AP Clavicle XR
30yo woman with transverse fracture lateral to the conoid
tubercle with intact CCL, treated nonoperatively

Apical Oblique Clavicle XR
86yo woman with oblique fracture lateral to the conoid tubercle
with intact CCL, treated nonoperatively
Some lateral clavicular fractures extend into the ACJ; these can usually be managed
conservatively with good results
AP Clavicle XR
37yo woman with oblique nondisplaced
fracture extending into an otherwise intactappearing ACJ, treated nonoperatively
1.
2.
Neer CS. J Trauma. 1963:99-110
Jackson WF, et al. J Trauma 2006; 61:222-5
GROUP II
AP Clavicle XR

Fractures most likely to displace (and therefore
heal poorly) are:
◦ near the conoid tubercle with associated rupture1 or
avulsion2 of the CCL
◦ just medial to the conoid tubercle of the CCL

In both cases, the lateral fragment is pulled
inferiorly, while unopposed forces on the medial
fragment result in wide fracture displacement
(see next slide)
◦ Surgery may be considered – may require
specialized fixation due to problems of bone quality
and comminution, including fixation to the coracoid
(e.g. suture button) or the acromion (hook plate)
28yo man with clavicle fracture lateral to the
conoid tubercle. Although the tubercle (arrow)
is spared, the CCL is disrupted, inferred by
elevation of the medial clavicular fragment (and
widening between the conoid tubercle and
coracoid process)
1.
2.
Neer CS. J Trauma. 1963:99-110
Jackson WF, et al. J Trauma 2006; 61:222-5
25 yo man with comminuted fracture of the lateral clavicle, including an inferior fragment containing the CCL attachment sites.
This was treated with a plate and screws and suture button fixation from the plate to the coracoid – note the metallic button
(arrow) on the undersurface of the coracoid. This prevents pull-out of the screws from the distal comminuted fragments
AP Clavicle XR
Post-op AP Clavicle XR
GROUP II

Displacing forces shown below result in a higher rate of nonunion for lateral fractures
than for midshaft fractures
Requirements for Displacement:
1

Distal fracture medial to conoid tubercle, OR

Fracture at or lateral to conoid tubercle, AND
Avulsion of conoid tubercle or widening
between conoid tubercle and coracoid =
conoid ligament torn (example shown)
Trapezius
AC
T
L
Displacing Forces:
1.
4
1.
Pectoralis
major
3
Trapezius muscle pulls medial fragment
superior and posterior; muscle may become
entrapped
2. Weight of arm pulls lateral fragment down
Bahk MS, et al.3.
J Bone
Joint Surg Am.
2009;91:2492-2510
Pectoralis
muscle
pulls humerus & therefore
lateral fragment medial
4.
Scapula acting via AC and trapezoid (TL)
ligaments rotates lateral fragment up to 40o
2
Arm
1. Neer CS. Clin Orthop Relat Res 1968; 58:43-50
2. Neer CS. J Trauma 1963:99-110
GROUP III

Uncommon fractures of the medial ⅓ of the clavicle, usually treated nonoperatively
unless open1

Described as transverse, oblique, comminuted, or avulsive, and can be intraarticular
or extraarticular

Radiographically subtle due to overlapping structures, these fractures are best
visualized and characterized on CT1
Cor CT
AP CXR (cropped)
58yo man with trauma to left shoulder. Initial CXR shows asymmetric
positioning of the clavicles, suspicious for clavicle dislocation. However,
subsequent CT images show displaced, extraarticular, oblique fracture of
the medial left clavicle. The shaft fragment is displaced inferior and
anterior relative to the clavicular head, accounting for the XR appearance
1. Throckmorton T, Kuhn JE. J Shoulder Elbow Surg 2007; 16:49-54
Ax CT
GROUP III

Medial clavicular fractures are a marker of high-energy trauma and occur in a trauma
population with high mortality

Presence of a medial clavicular fracture should prompt CT to look for coexisting
injuries, including hemothorax/pneumothorax, pulmonary contusions, ARDS, rib
fractures, facial and head injuries, cervical spine injuries1
Coronal CT
AP Clavicle XR
15yo boy s/p MVC with right pulmonary contusions and
segmental clavicle fx involving the midshaft (black
arrow) and medial clavicle (yellow arrow)
AP CXR
1. Throckmorton T, Kuhn JE. J Shoulder Elbow Surg 2007; 16:49-54
Fracture location
Middle third fracture
Important factors affecting treatment decisions
completely displaced (>100%)
≥2 cm shortening
z-shaped fragment
skin tenting, open injury
Lateral third fracture
fracture at, medial to, or lateral to conoid tubercle
displaced medial fragment (>100%)
CCL avulsion
Medial third fracture
fracture description + additional injuries

The acromioclavicular joint (ACJ) at the distal end of the clavicle has a synoviumlined joint capsule stabilized by superior, inferior, anterior, and posterior
acromioclavicular (AC) capsular ligaments
◦ The superior AC capsular ligament is the most important component and is
reinforced by fibers of the deltoid and trapezius muscles
◦ The AC ligaments primarily prevent anterior and posterior displacement

The coracoclavicular ligament (CCL) is composed of the fan-shaped conoid ligament
medially and the quadrilateral-shaped trapezoid ligament laterally
◦ The CCL primarily resists vertical displacement

The deltoid and trapezius muscular aponeuroses converge over the ACJ to form the
deltotrapezial fascia

ACJ alignment is best assessed on a Zanca view, but the AP view is usually sufficient
in the ED
Normal ACJ alignment is maintained by the:
•
ACJ capsule and AC ligaments
•
conoid and trapezoid components of the CCL
•
coracoacromial ligament
•
deltotrapezial fascia (aponeurosis) (DTF)
Diagram of normal measurements for ACJ alignment1
Deltotrapezial fascia
Trapezius m.
.
ACJ capsule +
AC ligaments
Deltoid m.
Conoid
Ligament
Trapezoid
Ligament
CCL
Coracoacromial
Ligament
Diagram of ACJ structures
Normal ACJ alignment on XR1:
• 5-8 mm ACJ and <2-3 mm
contralateral asymmetry
• Inferior cortex of distal clavicle aligns
with that of acromion
• 10-13 mm CC interval and <5 mm
contralateral asymmetry
1. Eschler A, et al. Arch Orthop Trauma Surg. 2014;134:1193-8

ACJ separations are described according to the modified Rockwood classification1

Six types of injury exist, based on integrity of the AC ligaments, CCL, and DTF and
on the ultimate location of the distal clavicle
◦ Type VI injury (dislocation of clavicle inferior to the coracoid process) is extremely rare and will
not be discussed further, though important because it is treated surgically
Modified Rockwood Classification
Upward displacement of
clavicle *
Pathology
Treatment
I
0% (radiographically occult)
AC ligament sprain with intact AC capsule
Non-operative
II
0-50%
AC ligament tear, normal or sprain of CCL
Non-operative
III
50-100%
AC ligament and CCL torn, DTF intact – distal clavicular
subluxation is reducible
Often non-operative,
consider ORIF
IV
50-100% + posteriorly
displaced on axillary
AC ligament and CCL torn, DTF torn with distal clavicle
button-holed posteriorly through trapezius
Surgical
V
100-300%
AC ligament and CCL torn, DTF torn with distal clavicle
button-holed superiorly through trapezius
Surgical
* Originally described as % of CC interval. However, without prior knowledge of the
patient’s normal CC interval, % of the width of the clavicle is an adequate approximation
1. Rockwood CA, Young DC. Disorders of the acromioclavicular joint. In: Rockwood CA,
Matsen FAI, eds. The Shoulder. Philadelphia: WB Saunders; 1990. p. 413-76
II
Upward displacement of clavicle
Pathology
Treatment
0-50%
AC ligament tear, normal or sprain of CCL
Non-operative

Rockwood Type II injury results from tear of the AC
ligament but other structures are intact

Only the ACJ is wide and/or minimally vertically
offset

Potential mimics include distal clavicular osteolysis
or surgical resection of the distal clavicle (Mumford
procedure) – look for truncated appearance of the
clavicle + widening of AC joint interval without
vertical offset
52yo woman with type II ACJ separation, slight vertical
offset of the ACJ without significant widening
AP Clavicle XR
Diagram of grade II ACJ separation
54yo man with type II ACJ separation, widening of the
ACJ without vertical offset
AP Clavicle XR
III
Upward displacement of clavicle
Pathology
Treatment
50-100%
AC ligament and CCL torn, DTF intact –
distal clavicular subluxation is reducible
Often non-operative,
consider ORIF

Tears of both the AC ligaments and CCL give rise to the
Rockwood Type III injury; DTF remains intact

AC and CC intervals are both wide

This injury is readily reducible with upward force applied
to the elbow

This injury may be treated operatively or non-operatively,
depending on surgeon and patient factors. Most often,
conservative management is offered with surgery for
failure of nonoperative treatment
Diagram of grade III ACJ separation
42yo man with type III ACJ separation. Upright clavicle radiographs show ~100% vertical offset of left ACJ and widening of
CC interval. However, supine radiographs show only minimal widening of ACJ, confirming reducibility
Upright
Supine
IV




Upward displacement of clavicle
Pathology
Treatment
50-100%
+ posteriorly displaced on axillary
AC ligament and CCL torn, DTF torn with distal clavicle
button-holed posteriorly through trapezius
Surgical
If DTF is also torn, the distal clavicle may become
entrapped within the fascial defect or within the
trapezius muscle
In Rockwood Type IV injuries, the clavicle is displaced
posteriorly into a subcutaneous position, which might
be visible on axillary radiographs as posterior
displacement of at least 100% of the clavicle width1
This injury is not reducible with upward force applied to
the elbow
This injury is treated operatively
Diagram of grade IV ACJ separation
66yo man hit by truck with grade IV ACJ
separation. The clavicle is vertically
offset 100% on the AP view, which can
be seen with grade III or even grade IV
injuries. However, on the axillary view,
the clavicle (black arrows) is also
posteriorly displaced relative to the
acromion (white arrows), indicating grade
IV injury
AP XR
Axillary XR
1. Cho CH, et al. J Shoulder Elbow Surg 2014;
23:665-70
IV

Upward displacement of clavicle
Pathology
Treatment
50-100%
+ posteriorly displaced on axillary
AC ligament and CCL torn, DTF torn with distal clavicle
button-holed posteriorly through trapezius
Surgical
However, it is important to recognize that the distal clavicle can project posterior
relative to the acromion even when there is no ACJ separation (see example below)1
AP Shoulder XR
Axillary Shoulder XR
63yo woman with mild ACJ degeneration but normal alignment on AP view. However, the distal clavicle (black arrows)
artifactually projects posterior to the acromion (white arrows) on the axillary view

Reliable differentiation of types III and IV therefore requires correlation of the
radiographic and physical exam findings. CT can also be helpful for problem solving
1. Rahm S, et al. J Orthop Trauma 2013; 27: 622-626.
V
Upward displacement of clavicle
Pathology
Treatment
100-300%
AC ligament and CCL torn, DTF torn with distal
clavicle button-holed superiorly through trapezius
Surgical

The distal clavicle may also displace superiorly through
the torn DTF. This results in more marked elevation of
the clavicle, between 100-300%

This injury is also not reducible with upward force applied
to the elbow

This injury is treated operatively

The possibility of a type V injury should be raised for
those injuries with the clavicle displaced more than 100%
above the acromion, realizing that there is a grey zone
between type III and type V injuries around 100%
displacement
52yo man with type V ACJ separation. Clavicle radiograph at
right shows more than 200% vertical offset of left ACJ and
widening of CC interval. Soft tissue gas was related to left rib
fractures, not an open
injury. The patient was
treated operatively with
CCL reconstruction
(osseous tunnels indicated
by arrows on left image)
Post-op AP Clavicle XR
AP Clavicle XR
Diagram of grade V ACJ separation



Pediatric pseudodislocation is characterized by the appearance of ACJ dislocation
and CCL tear
Instead of the CCL tearing, however, the intact ligaments are attached to a periosteal
sleeve arising from the distal clavicle.1 The diaphysis herniates superiorly through the
periosteal defect while the epiphysis, periosteal sleeve, and CCL remain in place
The periosteal sleeve regenerates new bone, and these children often do well with
nonoperative management
15yo boy with widened ACJ and CC interval related to
football injury. A bone fragment lies underneath the distal
clavicle, which represented a small cortical fragment
attached to the periosteal sleeve and epiphysis avulsed
by the CCL
AP Clavicle XR
17yo girl with ACJ separation following MVC. Radiographs show
widening of the ACJ and CC interval. At surgery, type V ACJ
separation was diagnosed due to additional DTF disruption.
However, the CCL was actually intact but was attached to an
avulsed periosteal sleeve (without associated radiographic finding)
AP Clavicle XR
1. Falstie-Jensen S, Mikkelsen P. JBJS. 1982;64B:368-369
Components of the SSSC

The superior suspensory shoulder complex
(SSSC) is an osseoligamentous ring formed by
acromion process, acromioclavicular joint
capsule, distal clavicle, coracoclavicular
ligaments, coracoid process, and glenoid
process1

Multiple injuries to the SSSC potentially
destabilize the arm relative to the shoulder girdle
and are important to recognize. They result in a
“floating shoulder”2

Originally identified when scapular neck and
ipsilateral clavicular shaft fractures coexist,3-4 the
floating shoulder can also result from grade III or
higher ACJ separations and unstable distal
clavicle fractures2

One or more of the sites of disruption in a
floating shoulder may be surgically repaired
ACJ
Coracoid
Osseoligamentous ring of the SSSC
1.
2.
3.
4.
Lambert S, et al. Injury 2013; 44:1507-13
Goss TP. J Orthop Trauma 1993; 7:99-106
van Noort A, van der Werken C. Injury 2006; 37:218-27
Herscovici D, et al. JBJS 1992; 74B:362-4
26yo man with floating shoulder resulting from
comminuted scapular fracture traversing the glenoid
neck and acromial process combined with grade III ACJ
separation. Due to extensive neurologic and other
injuries resulting from being hit by a train, this injury was
treated conservatively despite being unstable
Grashey Shoulder XR
25yo man with floating shoulder resulting from moderately
displaced mid clavicular shaft fracture and glenoid neck
fracture. He underwent surgical fixation of the clavicular shaft
only, with successful conservative treatment of the scapular
neck
AP Shoulder XR
Post-op AP Clavicle XR


While the osseous anatomy of the sternoclavicular joint (SCJ) is not intrinsically
stable, SCJ dislocation is rare due to strong
ligaments supported by a dynamic
muscular envelope
SCM
sternal clavicular
head
head .
6 5
3 1
The anterior & posterior joint capsule
(sternoclavicular ligaments) (1) plays primary
stabilizing role
2
4
7
◦ disruption of anterosuperior/posterior capsular
thickening or “ligament” allows superior translation
of joint1

Secondary stabilizing roles played by the interclavicular (2) and costoclavicular
(rhomboid) (3) ligaments and the dynamic muscular envelope
◦ subclavius muscle (4) acts as extrinsic shock-absorber for the clavicle and SCJ
◦ sternocleidomastoid (SCM) and pectoralis major form an muscular aponeurosis anterior
to SCJ
◦ sternohyoid (5) and sternothyroid (6) muscles lie directly behind the SCJ

An intraarticular disc (7) separates the clavicular head from the manubrium and
can be torn or crushed
1. Robinson CM, et al. JBJS 2008; 90B:685-96
2. Lee JT, et al. JBJS. 2014;96A:e166

Injury can range from minimal sprain of the supporting ligaments without laxity to
rupture of the sternoclavicular ligaments only, resulting in subluxation and mild
deformity, and finally to complete rupture of the sternoclavicular and costoclavicular
ligaments resulting in anterior or posterior dislocation
◦ Anterior dislocation is more common, often from an indirect force directed against the lateral
clavicle
*
AP CXR (cropped)
3D Volume-rendered CT
42yo pedestrian hit by car with anterior left SCJ dislocation. AP CXR shows asymmetric position of the clavicular heads
(yellow dashed outlines). Volume rendered CT shows normal right SCJ (arrow) and anteriorly dislocated left clavicle (*)

Though SCJ dislocation may be detected on AP or serendipity radiographs of the
joint, CT is the mainstay of diagnosis
1. Robinson CM, et al. JBJS 2008; 90B:685-96


Posterior dislocations are much less
common but are associated with more
complications, the most worrisome of
which is vascular or aerodigestive tract
injury from the clavicular head. CT
should be performed in these patients
AP Clavicle XR
Surgical indications include:
◦ failure of closed reduction of anterior
dislocation
◦ neurovascular compromise
◦ open fracture-dislocation
◦ closed reduction of posterior dislocation is
only performed in the OR with
cardiothoracic surgery available in case of
complications
29yo man with posterior right SCJ dislocation. AP
radiograph shows asymmetric position of the clavicular
heads (yellow dashed outlines). On apical oblique view,
the right clavicular head moves more inferior relative to the
left, suggesting posterior dislocation. This is easily
confirmed on axial MIP CT. Slight anteroposterior tracheal
narrowing is an artifact of the MIP reconstruction – no
airway or other soft tissue injury was identified
Apical Oblique Clavicle XR
Axial 3D MIP CT
1. Robinson CM, et al. JBJS 2008; 90B:685-96

Asymmetric widening or superior subluxation of the sternoclavicular joint without
anteroposterior malalignment is worth mentioning, as it directs attention to a joint that
may be sprained or have some pre-existing inflammatory or degenerative process,
although this can usually be treated conservatively
51yo woman with asymmetric widening of the left SCJ
without anteroposterior displacement after MVC. This
was treated conservatively
Coronal CT
25yo man isolated superior dislocation of the right
SCJ without anteroposterior displacement. CXR
shows slight asymmetry of the medial clavicles
Coronal CT
CXR (cropped)

The medial clavicular epiphysis is the last to appear (around 18yo) and to fuse
(between 23-30yo, usually around 25yo)

Many “dislocations” in those <25yo are not dislocations but actually physeal injuries
16yo girl with Salter-Harris type 1 injury of the medial clavicle during a basketball game. Clinically and radiographically
(not shown), the injury mimics a posterior SCJ dislocation, but CT (axial MIP reconstruction shown) confirms that both
clavicular epiphyses (black arrows) are in normal position, with right-sided physeal disruption and posterior metaphyseal
(M) displacement. She also had mediastinal hematoma (*) ascribed to venous bleeding and a small pseudoaneurysm of
the brachiocephalic vein (yellow arrow) on coronal CT reformation
*
M
Axial MIP CT
Coronal CT
1. Bishop JY, Flatow EL. Clin Orthop Relat Res. 2005;432:41-48

Scapulothoracic dissociation is a rare but severe injury of the osseous and/or
muscular shoulder girdle and potentially involving the subclavian / axillary vascular
structures and/or brachial plexus.1 It is not specifically a clavicular injury, although
the clavicle or surrounding articulations are often affected, and the clavicular injury
may be the first imaging clue to this important diagnosis

Focused neurovascular exam is required to prompt appropriate work-up, including:
◦ Emergent CT angiogram for evaluation of suspected vascular injuries (see Fig)
◦ MR neurogram obtained after a delay of
several days for suspected brachial
plexus injury, which if complete will often
render the arm functionless with a poor
long-term prognosis
20yo man with scapulothoracic dissociation from
motorcycle crash. CT angiogram (3D volume rendered
reconstruction shown to right) confirmed complete
occlusion of the left axillary artery with distal reconstitution
3D Volume Rendered CT angiogram
1. Brucker PU, Gruen GS, Kaufmann RA. Injury. 2005;36:1147-55

The scapula is usually lateralized from
the ribs relative to the normal side

Quantified with scapular index
◦ ratio of distances bilaterally from medial
border of scapula to spinous process
The 20yo male motorcyclist with left scapulothoracic
dissociation (with CTA shown on previous slide).
At
presentation, suspicious radiographic findings included
increased scapular index (A/B), comminuted left scapular
fracture (S), increased soft tissue density in the left axillary &
supraclavicular regions (*), and left apical capping (arrows)
◦ ≥1.4 is considered abnormal
◦ prone to error (beware asymmetric arm
positioning, spine fractures, or scapular
fractures)
*
S
◦ should not definitively rule in or exclude
this diagnosis1

Distracted fractures of the clavicle or
separations of the ACJ or SCJ often
present

Secondary signs from chest wall
hematoma accompanying the vascular
injury
*
Scapular index = A / B
◦ asymmetric increased axillary density
◦ ipsilateral apical capping
1. Brucker PU, Gruen GS, Kaufmann RA. Injury. 2005;36:1147-55
Thank you for viewing this Education Exhibit on Clavicle Trauma

Fractures of the middle third of the clavicle that demonstrate >2 cm of
shortening, >100% translation without osseous contact, and/or segmental
comminution may be considered for surgical repair

Fractures of the lateral third of clavicle, including at the level of or just
medial to the coracoclavicular ligaments, have higher rates of nonunion and
therefore may also be repaired surgically

The modified Rockwood classification is used to describe the degree and
direction of displacement in AC separation, and injuries of grade IV or V (or
extremely rare grade VI) are repaired surgically

Associated injuries are common in medial clavicular fractures and
sternoclavicular joint injuries, and additional imaging with CT is
recommended, particularly if displacement is posterior
Author Contact Info: Claire Sandstrom - [email protected]