Clavicle Fractures
A clavicle fracture is a common injury seen after a fall on an
outstretched arm or direct impact. A large majority of all clavicle
fractures will occur in the middle third of the shaft. Traditionally,
treatment was based on the premise that malunion (or even non-union) of
clavicle fractures was well tolerated and imposed little morbidity.
Accordingly, these fractures were usually treated with only a course of
immobilization. Recently, that assumption has been questioned, and a
greater number of clavicular fractures are currently treated operatively.
Clavicular fractures that occur far laterally (known as distal clavicle
fractures) must be considered distinctly, as they may involve the
ligaments that suspend the glenohumeral joint. Also, because the
clavicular physis is among the last to close (around age 21 or later), an
apparent separation of the acromioclavicular joint in a young adult may
actually represent a physeal fracture of the clavicle.
Structure and Function
The clavicle (known colloquially as the collarbone), is a strut between
the scapula (shoulder blade) and the sternum (breastbone).
Viewed from above, the clavicle is shaped like a capital “S”, attaching
medially to the sternum at the sternoclavicular joint, and laterally to
the coracoid and the acromion. The inflexion point – the middle of the S –
is the portion of the bone most prone to fracture.
The pectoralis major, sternocleidomastoid and deltoid muscles originate
from the clavicle and the trapezius inserts on it (Figure 1).
Figure 1: The left clavicle as seen from above. The sternum is
medial and the acromion is lateral. The points of muscular
attachment are color-coded: medially, the sternocleidomastoid is red
and the pectoralis is green; laterally the deltoid is yellow and the
trapezius is orange. (modified from
https://en.wikipedia.org/wiki/Clavicle#/media/File:Gray200.png)
When the clavicle is fractured, the proximal (medial) portion can be
pulled superiorly by the sternocleidomastoid muscles, while the distal
portion is pulled inferiorly by the weight of the arm. The fracture
fragments can also be displaced superiorly or posteriorly, leading to
tenting and necrosis of the overlying skin or neurovascular injury,
respectively.
The coracoclavicular ligaments, namely, the trapezoid and conoid, attach
from the coracoid process to the inferior aspect of the clavicle and help
suspend the arm. The acromioclavicular ligaments resist anterior/posterior
displacement of the distal clavicle relative to the acromion. The clavicle
overlies the brachial plexus, as well as the jugular and subclavian blood
vessels.
Patient Presentation
Clavicle fractures most commonly occur following a direct blow or after a
fall on an outstretched arm. Patients will often report feeling a snapping
sensation at the time of injury. Patients may present with the relative
arm held by their other hand across the body in adduction. Movement of the
arm will exacerbate the pain.
In the case of mid-shaft fractures, there may be a deformity of the
fractured clavicle, with swelling and ecchymosis. Skin tenting from
anterior displacement may be present as well. The proximal portion of the
fractures may be pulled superiorly, while the distal portion may be pulled
inferiorly.
Distal clavicle fractures (Figure 2) may present with no deformity, and
tenderness around the acromioclavicular (AC) joint, similar to an AC joint
separation.
Figure 2: A distal (lateral) clavicle fracture (red arrow) may be in
the region (green star) of the ligaments that attached the clavicle to
the scapula. (from https://radiopaedia.org/cases/22256)
A neurovascular and respiratory exam is critical to rule out
injury to
the brachial plexus, subclavian vessels, or the lungs. Strength,
sensation, pulses and difficulty of breathing should be assessed.
Objective Evidence
An anteroposterior chest radiograph showing both clavicles should be
obtained if a clavicle fracture is expected. This can differentiate
clavicle fractures from AC joint separations and sternoclavicular (SC)
dislocations. The chest radiograph can also be used to assess for signs of
vascular damage, such as a widened mediastinum and to rule out a
pneumothorax.
Radiographs should also be obtained to rule out injuries to the
glenohumeral joint and scapula. The required radiographs include the
anterior-posterior (AP), axillary, and lateral (“scapular-Y”) views. Most
mid-shaft fractures can be visualized with this view.
Anteroposterior radiographs can best assess a clavicle fracture,
especially in the proximal portion of the clavicle (Figure 3). A
posteroanterior radiograph can be used to assess shortening of the
clavicle for surgical planning (Figure 4). Computed tomography (CT)
imaging can be utilized for evaluation of intra-articular involvement of
the medial and lateral ends of the bone; CT is not needed for acute
midshaft injuries.
Figure 3: A mid-shaft clavicle fracture. (Case courtesy of A. Prof
Frank Gaillard, https://radiopaedia.org/ From the case
https://radiopaedia.org/cases/18050)
Figure 4: Shortening of the clavicle can be assessed by either of
the following methods. On the left, the overlap between the ends
of the medial and lateral fragments is measured directly, this is
shown in red. At right, the entire medial-to-lateral length of
both the injured and the normal clavicle are measured. As shown,
the blue line represents the length of the shortened clavicle, the
green line shows the length of the normal one, and the red line
represents the difference. (from
https://bmcmusculoskeletdisord.biomedcentral.com/articles/10.1186/s12891-017-1881-x)
Arteriography may be helpful in evaluating vascular injury.
Clavicle fractures are classified by location. The regions of the clavicle
are segmented into thirds: medial (aka proximal), middle and lateral
(distal). Mid-shaft clavicular fractures represent an overwhelming
majority of these injuries (80%). Among the distal clavicular fractures
(close to the AC joint) the fractures are further classified (following
the scheme of Neer) in terms of the location of the clavicle fracture
relative to the coracoclavicular ligaments. These fractures are designated
as medial to the coracoclavicular ligaments; between the two
coracoclavicular ligaments (with an intact trapezoid ligament attached to
the distal lateral segment); and lateral to coracoclavicular ligaments and
thus extending into the acromioclavicular joint itself.
Clavicle fractures are also classified by the degree of
displacement,
nondisplaced, incompletely displaced (that is, some overlap of the
fracture edges), and completely displaced.
Epidemiology
Clavicle fractures account for 2-5% of fractures in adults and
10-15%
of fractures in the pediatric population. Approximately 70% of clavicle
fractures occur in males. There is a bimodal distribution of age, with
the highest rates of fracture in active patients below the age of 25
years old and patients above the age of 55 years old. Falls, motor
vehicle accidents, and sports-related injuries are the most common
causes of clavicle fractures in adults.
Differential Diagnosis
As with many traumatic injuries, the differential diagnosis narrows
considerably after radiographs are obtained: the bone is either broken or
it is not.
If there is no fracture, a clavicular contusion might be the diagnosis.
The presentation is similar to that of a clavicle fracture with swelling,
ecchymosis, tenderness and limited range of motion secondary to pain.
Also, a ligament injury (especially in the form of an acromioclavicular
joint separation) may be present. An acromioclavicular separation presents
as pain over the acromioclavicular joint and distal shoulder. There may or
may not be displacement of this joint. Sternoclavicular dislocation occurs
after direct trauma to the chest wall and may present with deformity of
the sternoclavicular joint and pain with arm movement. It is important to
evaluate for fractures of the scapula, including the acromion and glenoid.
If both the clavicle and glenoid neck are fractured, the glenohumeral
joint has no connection to the axial skeleton. This is known as a
"floating shoulder". These injuries are associated with
neurovascular injury. Rib fractures can also occur concomitantly with
clavicular fractures given the traumatic mechanism of injury.
Red Flags
Posterior or inferior displacement of a segment puts neurovascular
structures, as well as the lungs, at risk of injury.
Paresthesia, sensory deficits, strength deficits and/or abnormal reflexes
in the relative arm may indicate an injury to the brachial plexus or one
of its nerve branches.
Pulselessness, asymmetric pulses or coldness of limb may indicate an
injury of the subclavian artery or vein.
Difficulty breathing and chest pain may indicate the presence of rib
fractures, a hemothorax (vascular trauma), or a pneumothorax.
Treatment Options and Outcomes
Immobilization is indicated for fractures that are no more than minimally
displaced – the majority of clavicle fractures. With this injury, the
patient is initially placed in a sling, with gentle range of motion
exercises started at ~2 weeks post injury, when patients are able to move
the arm without pain. Strengthening exercises can be started 6 to 10 weeks
after injury, when there is radiographic evidence of healing. Return to
contact sports is typically allowed after 4 to 5 months, when there is
radiographic evidence of fracture union.
Patients with clavicle fractures that are completely displaced and
foreshortened by 2 cm or more are commonly indicated for surgery (Figure
5). If the ends of the fracture are not in contact and the clavicle is
shortened by 2 cm or more, the risk of non-union increases. This rationale
is controversial, in the sense that delayed open treatment can be reserved
for symptomatic non-unions and malunions. Also, not every patient with a
displaced and foreshortened fracture will be sufficiently symptomatic to
warrant further treatment.
Figure 5: A clavicle fracture fixed with a plate. (from
https://bmcmusculoskeletdisord.biomedcentral.com/articles/10.1186/1471-2474-15-380)
Any displacement of distal third fractures may be an indication for
surgical treatment as the displacement implies a concomitant ligament
injury and higher risk of non-union.
Urgent open treatment is indicated for open fracture (or skin tenting),
with subclavian artery or vein injury, or when there is a scapular
fracture as well (the so-called floating shoulder).
Polytrauma may also be an indication for open treatment for a fracture
that, in isolation, would be indicated for closed treatment.
Open reduction and internal fixation can utilize intramedullary rods, or
plates and screws. After internal fixation, patients are immobilized in a
sling for 2 weeks; during this time passive range of motion exercises are
performed. Rehabilitation is similar to non-op management.
While patient satisfaction and shoulder function is typically high
following non-operative immobilization, there is a risk of malunion and
nonunion. The risk of nonunion increases with increasing amounts of
displacement.
Non-operative treatment is also associated with higher rates of cosmetic
dissatisfaction compared to operative treatment.
Open reduction and internal fixation is associated with shorter time to
union and better functional recovery. Compared to closed reduction and
immobilization, surgical fixation results in significantly better outcomes
6 weeks after injury, but this difference dissipates after about 6 months.
Unfortunately, there is a high complication rate, as high as 34%, and a
significant reoperation rate, ranging from 18-25%. (Often, the second
surgery is for hardware removal, not failure of the first operation.)
Risk Factors and Prevention
Athletic involvement increases the risk for clavicle fracture.
The use
of protective equipment when participating in contact sports may
decrease the risk of clavicle fracture.
Miscellany
For about 2,390 out of the last 2400 years, non-operative treatment of
clavicular fractures was the norm. In 400 BC, Hippocrates wrote this about
clavicle fractures, “Patients attach much importance to it, as supposing
the mischief greater than it really is, and the physicians bestow great
pains in order that it may be properly bandaged, but in a little time the
patients, having no pain, nor finding any impediment to their walking or
eating, become negligent, and the physicians finding they cannot make the
parts look well, take themselves off, and are not sorry at the neglect of
the patient, and in the meantime the callus is quickly formed.” Likewise,
in 1994, Mullaji and Jupiter (Injury. 25(1):41-5, 1994 Jan) said this:
“Internal fixation of the clavicle is rarely necessary.”
It was not until 2007 that the Canadian Orthopedic Trauma Society wrote:
“Operative fixation of a displaced fracture of the clavicular shaft
results in improved functional outcome and a lower rate of malunion and
nonunion compared with nonoperative treatment.” (Journal of Bone &
Joint Surgery – American Volume. 89(1):1-10, 2007)
Clavicle fractures are the most common fractures in newborns. Many of
these injuries are diagnosed after the baby and mother are discharged from
the hospital post-partum. Brachial plexus injuries can also occur during
these fractures, but almost always resolve.
Key Terms
Clavicle, collar bone, fracture, open reduction,
immobilization
Skills
Perform an upper extremity musculoskeletal exam with concern
for
neurovascular injury. Interpret radiographs of the chest and shoulder
for clavicle fractures, as well as other concerning signs such as rib
fractures or widened mediastinum. Apply a sling or figure-of-eight brace
to a patient.