Shoulder trauma

Acromioclavicular Joint Injury

Case

A 19 year-old male presents to the emergency department with a complaint of right shoulder pain. He was tackled from behind in a rugby game three days prior to presentation and has been experiencing pain over the anterior aspect of his right shoulder since that time. Physical exam is notable for tenderness over the right acromioclavicular (AC) joint and pain with both active and passive range of motion of the right shoulder. X-rays (Figure 1) show “no obvious fracture or subluxation.” However, based on your exam and clinical suspicion, closer inspection reveals abnormal alignment between the clavicle and the acromion consistent with AC joint injury.

Figure 1

Figure 1

The Acromioclavicular Joint

The acromioclavicular joint is formed by the AC ligament and the coracoclavicular (CC) ligament (Figure 2). The AC ligament provides horizontal stability to the joint while the CC ligaments provide vertical stability. (1)

In normal configuration, the inferior cortices of the clavicle and acromion are in alignment (Figure 3). Additionally, the coracoclavicular distance is normally less than 13 mm or there is a less than 5 mm difference between the left and right coracoclavicular distances. (1; 3) Figure 4 depicts normal alignment of the inferior cortices of the acromion in red and highlights the coracoclavicular distance in white.

Figure 2

Figure 2

Figure 3

Figure 3

Figure 4

Figure 4

Mechanism of Injury, Physical Examination, and Diagnosis

Acromioclavicular joint subluxation and dislocation account for approximately 10% of all traumatic shoulder injuries. (1; 3) AC joint injury results from either direct or indirect injury to the shoulder. Direct injury to the joint occurs with a direct blow to the shoulder or, more commonly, when an individual falls with their arm in an adducted position. Indirect injury to the AC joint typically occurs as a result of a fall on an outstretched hand. (1; 4) On exam, patients will have pain over the acromioclavicular joint and pain with range of motion of the shoulder. (3) Patients may hold their arm in an adducted position and there may be a visible or palpable step-off deformity over the AC joint. Additionally, the ipsilateral clavicle may appear to be high-riding or the ipsilateral shoulder may appear displaced inferiorly (Figure 5). (1; 3) In less obvious cases, provocative maneuvers (such as the cross-body adduction test and AC shear test) may be used to localize discomfort to the AC joint. (2)

If acromioclavicular joint injury is suspected, three-view radiographs of the shoulder (anteroposterior view, scapular-Y view, axillary view) and a Zanca view (a specialized anteroposterior radiograph which removes the scapula from behind the joint) allow for identification of vertical displacement of the clavicle and for anteroposterior displacement of the clavicle. (2) AP comparison views of both AC joints can also be helpful in diagnosis of AC joint injury.

Figure 5

Figure 5

Acromioclavicular Joint Injury: Rockwood Classification

Acromioclavicular joint injuries are characterized by the degree of damage to the AC ligament and the CC ligaments. (3). These injuries are further classified using the Rockwood System (Figure 6).  

Figure 6

Type I

AC Ligament Sprain
CC Ligament Intact
Joint Capsule Intact

Inferior cortices of the
clavicle and acromion
are aligned.

Type II

AC Ligament Rupture
CC Ligament Sprain
Joint Capsule Rupture

The CC distance is
increased <25%
compared to the
contralateral AC joint.

Type III

AC Ligament Rupture
CC Ligament Rupture
Joint Capsule Rupture

The CC distance is
increased 25-100%
compared to the
contralateral AC joint.

Type IV

AC Ligament Rupture
CC Ligament Rupture
Joint Capsule Rupture

The clavicle is displaced
posteriorly towards the ipsilateral
trapezius. Identify on axillary
view radiograph.

Type V

AC Ligament Rupture
CC Ligament Rupture
Joint Capsule Rupture

The CC distance is
increased >100%
compared to the
contralateral AC joint.

Type VI

AC Ligament Rupture
CC Ligament Rupture
Joint Capsule Rupture

Clavicle is displaced
inferiorly and the distal
end is located
posterior to the
coracobrachialis and
biceps tendons.

Management

Non-Operative Management

  • Type I and Type II AC joint injuries are managed non-operatively. Patients should be immobilized in a sling for 7-14 days and should then proceed with progressive range of motion exercises. Return to full activity is indicated when patients are pain-free. (1; 3)

  • Type III AC joint injuries are often managed non-operatively with immobilization in a sling and range of motion/strengthening exercises. These individuals should be referred for outpatient orthopedic follow-up. (1)

Operative Management

  • Urgent orthopedic referral is indicated in patients with neurovascular compromise, skin tenting, and significant deformity. Additionally, Type IV-VI AC injuries are typically managed surgically and, as such, require urgent orthopedic consultation.

 

Case Outcome

The patient’s radiograph and clinical exam was most consistent with a Type III acromioclavicular joint injury. He was immobilized in a sling, provided with prescriptions for ibuprofen and acetaminophen, and instructed to follow up with orthopedics for further evaluation on an outpatient basis.

Faculty Reviewer: Dr. Jeffrey Feden


References

  1. Egol, K. A., Koval, K. J., & Zuckerman, J. D. (2010). Handbook of fractures. Lippincott Williams & Wilkins.

  2. Koehler, Scott M. (2018). Acromioclavicular joint disorders. UpToDate. < https://www.uptodate.com/contents/acromioclavicular-joint-disorders?search=acromioclavicular%20joint&sectionRank=2&usage_type=default&anchor=H9685354&source=machineLearning&selectedTitle=1~35&display_rank=1#H9685354>.

  3.  Marx, J., Walls, R., & Hockberger, R. (2013). Rosen's Emergency Medicine-Concepts and Clinical Practice E-Book. Elsevier Health Sciences.

  4.  Tintinalli, J. (2015). Tintinallis emergency medicine A comprehensive study guide. McGraw-Hill Education.


Images

Figure 1: Case courtesy of Dr Henry Knipe, <a href="https://radiopaedia.org/">Radiopaedia.org</a>. From the case <a href="https://radiopaedia.org/cases/30774">rID: 30774</a>

 Figure 2: Egol, K. A., Koval, K. J., & Zuckerman, J. D. (2010). Handbook of fractures. Lippincott Williams & Wilkins.

Figure 3: Richardson, Michael L. (1998). Radiographic anatomy of the skeleton: Shoulder—Internal rotation view. Obtained from <http://uwmsk.org/RadAnat/IntRotLabelled.html>.

Figure 4: Kang, K. S., Lee, H. J., Lee, J. S., Kim, J. Y., & Park, Y. B. (2009). Long term follow up results of the operative treatment of the acromioclavicular joint dislocation with a Wolter plate. Journal of the Korean Fracture Society, 22(4), 259-263.

Figure 5: Greene, Tim (ND). CoreEM: Acromioclavicular joint injury. Obtained from <https://coreem.net/core/ac-joint-injuries/>.

Figure 6:

Type I: Case courtesy of Dr Henry Knipe, <a href="https://radiopaedia.org/">Radiopaedia.org</a>. From the case <a href="https://radiopaedia.org/cases/28623">rID: 28623</a>

Type II: Case courtesy of Dr Henry Knipe, <a href="https://radiopaedia.org/">Radiopaedia.org</a>. From the case <a href="https://radiopaedia.org/cases/60140">rID: 60140</a>

Type III: Case courtesy of Dr Henry Knipe, <a href="https://radiopaedia.org/">Radiopaedia.org</a>. From the case <a href="https://radiopaedia.org/cases/30949">rID: 30949</a>

Type IV: Case courtesy of Dr Craig Hacking, <a href="https://radiopaedia.org/">Radiopaedia.org</a>. From the case <a href="https://radiopaedia.org/cases/64411">rID: 64411</a>

Type V: Case courtesy of Dr Bruno Di Muzio, <a href="https://radiopaedia.org/">Radiopaedia.org</a>. From the case <a href="https://radiopaedia.org/cases/44768">rID: 44768</a>

 Type VI: Case courtesy of Dr Jeffrey Hocking, <a href="https://radiopaedia.org/">Radiopaedia.org</a>. From the case <a href="https://radiopaedia.org/cases/48600">rID: 48600</a>

Sternoclavicular Joint Dislocation: Serious concern or not a big deal?

Case

A healthy 8-year-old girl was playing basketball and fell forward onto the anterior aspect of her right shoulder. When she rotates her shoulder in a circular motion, she feels a “popping” sensation in the middle of her chest. Her mother further notes a slight deformity near the center of her chest. She reports no other injuries and is not currently in pain.

Exam

Well-developed young female in no acute distress with full range of motion of her right shoulder. There is a palpable deformity at the right sternoclavicular joint without tenderness. A reproducible pop is evident with circumduction of the right shoulder. Neurovascular exam is normal. Skin is intact.

Clinical image showing a protrusion over the right SCJ. Corresponding AP plain film demonstrating widening of the SCJ

Clinical image showing a protrusion over the right SCJ. Corresponding AP plain film demonstrating widening of the SCJ

Diagnosis

Anterior sternoclavicular joint dislocation

Treatment

Sling for support/comfort, and outpatient orthopedics follow-up.

About Sternoclavicular Joint (SCJ) Dislocations

KaineJ Ortho Figure 3.jpg

The SCJ is the only true articulation of the upper extremity with the axial skeleton. It is a well-supported joint with multiple ligamentous attachments to surrounding structures and thick anterior/posterior sternoclavicular ligaments. Note that the joint closely overlies the vascular and airway structures of the mediastinum.

Injuries to the SCJ are rare, comprising less than 1% of all joint dislocations and only 3% of shoulder girdle injuries. The SCJ can be dislocated anteriorly or posteriorly.  A thorough neurovascular examination of the affected extremity is essential given the clavicle’s proximity to the brachial plexus and important vascular structures. SCJ injuries may include physeal fractures in young patients (the physis doesn’t fuse until the early to middle twenties!). CT is typically favored as the imaging modality of choice over plain radiographs.

Mechanism of injury

  • Direct - force applied to the medial aspect of the clavicle forces it posteriorly (i.e., MVC or when one athlete falls on top of another)
  • Indirect - force applied to the shoulder and is transmitted medially (commonly seen in football pileups or falls on an outstretched arm)
A - A posterior SCJ dislocation caused by a force applied to the posterolateral aspect of the shoulder.  B - An anterior SCJ dislocation caused by a force applied to the anterolateral aspect of the shoulder.

A - A posterior SCJ dislocation caused by a force applied to the posterolateral aspect of the shoulder.

B - An anterior SCJ dislocation caused by a force applied to the anterolateral aspect of the shoulder.

Anterior dislocation

  • The more common type of SCJ dislocation.
  • Largely a cosmetic defect, with minimal functional impairment in mild to moderate cases.
  • Most patients can be treated conservatively with a sling, NSAIDs, and ice. This typically results in a favorable outcome with the joint stabilizing in the subluxed position. Patients can be pain free in as little as 2-3 weeks and have full return to unrestricted activity by 3 months (~80% of patients show no functional impairment).
  • Closed reduction can be attempted. However, re-dislocation rates range from 21% - 100%.
  • Rarely is operative reduction indicated and, when performed, has mediocre outcomes.

Posterior dislocation – an orthopedic emergency

  • Less common than anterior SCJ dislocation.
  • 30% of posterior dislocations are associated with life-threatening complications due to mediastinal injury.
  • Extent of injury is best characterized by CT angiogram.
  • Emergent consultation of orthopedic surgery is recommended.
  • Reduction is best performed by orthopedics in the OR with vascular surgery readily available.
  • However, in the event of a pulseless limb, consider emergent reduction in the ER.
Axial CT image showing retropulsion of the medial aspect of the left clavicle behind the manubrium with potential compromise of the mediastinal structures. The corresponding anatomical diagram highlights the structures at risk.

Axial CT image showing retropulsion of the medial aspect of the left clavicle behind the manubrium with potential compromise of the mediastinal structures. The corresponding anatomical diagram highlights the structures at risk.

The most common reduction technique involves placing towels between the patient’s shoulder blades. Then, traction is applied to the affected arm while holding it in abduction (90 degrees) and extension (15 degrees). An assistant may be required to apply manual pressure to the medial aspect of the clavicle to facilitate reduction of an anterior dislocation. Similarly, an assistant may use a towel clip to percutaneously grasp a posteriorly dislocated clavicle and apply forward traction.

The most common reduction technique involves placing towels between the patient’s shoulder blades. Then, traction is applied to the affected arm while holding it in abduction (90 degrees) and extension (15 degrees). An assistant may be required to apply manual pressure to the medial aspect of the clavicle to facilitate reduction of an anterior dislocation. Similarly, an assistant may use a towel clip to percutaneously grasp a posteriorly dislocated clavicle and apply forward traction.

Take Home Points

  • Sternoclavicular joint injuries are rare injuries.
  • In younger patients be careful to look for physeal fracture and displacement.
  • Anterior dislocations can be conservatively managed and have favorable outcomes.
  • Posterior dislocations can be life threatening and require emergent orthopedic consultation.

Faculty Reviewer: Jeffrey P. Feden, M.D.

 

References

Morell DJ, Thyagarajan DS. Sternoclavicular joint dislocation and its management: A review of the literature. World J Orthop 2016 April 18; 7(4): 244-250

Jiang W, Gao Sg, Li Ys, Lei Gh. Bipolar dislocation of the clavicle. Indian J Orthop 2012;46:721-4

Roepke, Clare et al. Chest Pain Bounce-Back: Posterior Sternoclavicular Dislocation Annals of Emergency Medicine, Volume 66 , Issue 5 , 559 - 561

Bjoernsen, LP, Ebinger, A. Shoulder and Humerus Injuries. In: Tintinalli’s Emergency Medicine. 8th ed. New York: McGraw-Hill; 2016

Bengtzen, R, Daya, M. Shoulder. In: Rosen's emergency medicine: concepts and clinical practice 9th edition. Philadelphia, PA: Mosby/Elsevier; 2017

Egol, KA, Koval, KJ, Zuckerman, JD. Acromioclavicular and Sternoclavicular Joint injuries. In: Handbook of Fractures. 5th ed. Philadelphia, PA : Wolters Kluver; 2014

Thurston,M, Jones, J, et al. Sternoclavicular joint dislocation [Internet]. [Accessed August 15, 2017]. Available from: https://radiopaedia.org/articles/sternoclavicular-joint-dislocation

Cadogan, M. Sternoclavicular Joint Dislocation [Internet]. 2014. [Accessed on August 15, 2017]. Available from: https://lifeinthefastlane.com/sternoclavicular-joint-dislocation.

Weatherford, B. Sternoclavicular Dislocation [Internet] [Accessed on August 15, 2017]. Available from: http://www.orthobullets.com/trauma/1009/sternoclavicular-dislocation