The sternoclavicular joint is the most frequently moved, nonaxial
joint of the body. It also has the least amount of bony stability
of any major joint because less than half of the medial end of the
clavicle articulates with the upper sternum. Therefore, joint stability
depends on the integrity of the surrounding ligaments, which give
the sternoclavicular joint surprising strength. As a result, the
majority of injuries to this area are simple sprains, and dislocations
and fractures are uncommon.
Forcing the shoulder forward suddenly, or applying a medially
directed force to the shoulder, may result in a sprain to the sternoclavicular
joint. Pain and swelling are localized to the joint, and treatment
is symptomatic with ice, sling, and analgesics. Differential diagnosis
in the nontrauma patient should include consideration of septic
arthritis, especially in injection drug users.
Dislocations are unusual and typically result from motor vehicle
crashes or sports injuries. If the shoulder is rolled forward at
the time of impact, a posterior dislocation may result from a direct
blow or from an indirect force to the shoulder. An anterior sternoclavicular
joint dislocation may result from the same indirect force if the
shoulder is rolled backward at the moment of impact. Posterior sternoclavicular
joint dislocations are much less common than anterior dislocations.
Patients with a sternoclavicular joint dislocation have severe
pain that is exacerbated by arm motion and lying supine. The shoulder
appears shortened and rolled forward. On examination, anterior
dislocations have a prominent medial clavicle end that is visible
and palpable anterior to the sternum, although swelling and
tenderness may impede diagnosis. In posterior dislocations, the
medial clavicle end is less visible and often not palpable (Figure 268-1), and the patient may have signs and
symptoms of impingement of the superior mediastinal contents.
Right posterior dislocation shows less visible right
medial clavicle. (Courtesy of John Rudzinski, MD.)
Routine radiographs may not be diagnostic. Special views and
comparison with the other clavicle may be helpful. CT is the imaging
procedure of choice (Figures 268-2 and 268-3), and IV contrast may be administered
to further delineate injury to adjacent mediastinal structures (Figure 268-4).
Clavicle radiograph shows asymmetry of the clavicles. Arrow
indicates asymmetric and inferiorly displaced medial clavicle. (Courtesy
of Rockford Health System.)
CT scan shows right posterior sternoclavicular dislocation.
Arrow indicates disrupted sternoclavicular joint with posterior
displacement of clavicle and compression of adjacent lung. (Courtesy
of Rockford Health System.)
Sternoclavicular joints. The relationship of the sternoclavicular
joint to adjacent structures.
Patients with uncomplicated anterior dislocations may be
discharged without an attempted reduction, as this injury has little
or no impact upon function. For closed reduction, the patient
is placed supine with a towel roll or similar between the scapulae.
The arm is abducted to 90 degrees, traction is applied with slight
extension by moving the arm toward the ground, and pressure is placed
over the medial end of the clavicle.1 Even with
reduction, the joint is usually unstable and re-dislocates when
pressure is released. Clavicular splinting, ice, analgesics, and
orthopedic referral are required.
Posterior dislocations may be associated with life-threatening
injuries to adjacent structures, including pneumothorax or compression
or laceration of surrounding great vessels, trachea, or esophagus. Orthopedic
consultation is necessary for closed reduction, which ideally should
be performed in the operating room with trauma or vascular surgery
available.1 Open reduction may be necessary. For
closed reduction, patient positioning is the same as for anterior
reduction. The medial clavicle is manually grasped, or a towel clamp
is applied to the medial clavicle and then pulled upward, to relocate
the sternoclavicular joint.
The medial clavicular epiphysis is the last epiphysis of the
body to appear radiographically (age 18 years old) and the last
to close (age 22 to 25 years old). An apparent sternoclavicular joint
dislocation in children and young adults is typically a Salter-Harris type
I or II fracture, with either anterior or posterior displacement
of the clavicular metaphysis.2 Orthopedic consultation
is recommended because some patients will require reduction while
others will achieve adequate results with fracture healing and remodeling.
The clavicle provides support and mobility for upper extremity
tasks by functioning as a strut that connects the shoulder
girdle to the trunk. In addition, the clavicle protects the adjacent
lung, brachial plexus, and subclavian and brachial blood vessels. The
most common mechanism of injury is a direct blow to the shoulder. Transmission
of the compressive force results in a buckling of the clavicle,
which fractures once a critical force is achieved. Eighty percent
of clavicle fractures involve the middle third, 15% the
distal third, and 5% the medial third. Open fractures can
result from extreme tenting and piercing of the overlying skin.
Although the vast majority of clavicular fractures have a benign
course, serious associated injuries and complications may occur.
Trauma may result in associated injuries to the adjacent lung and
neurovascular structures. Children will often have a greenstick fracture
or a bowing deformity without a definite fracture.
Patients typically present with swelling, deformity, and tenderness
overlying the clavicle. The arm is slumped inward and downward and
is supported by the other extremity. Routine clavicle radiographs
may miss some fractures, particularly at either end of the bone,
due to overlap of surrounding structures. Definitive diagnosis may ...