Sternoclavicular joint injuries

Sternoclavicular joint dislocation is rare accounting for only 3% of all shoulder injuries. The sternoclavicular joint may dislocate anteriorly or posteriorly, the majority being anterior around 80 % Vs posterior 20%.
This follows high energy trauma and must be differentiated from the clicking or subluxing degenerate sternoclavicular joint they may affect people in their middle ages, they may first notice it following minor trauma.

Anatomy

The sternoclavicular joint is saddle-shaped, the medial head of the clavicle is larger than the fossa on the manubrium.

The joint has very little intrinsic osseous stability. The stability comes from the soft tissue, the strong anterior and posterior capsule. The interclavicular ligament and the costoclavicular ligament have secondary roles.

Mediastinal structures, the subclavian vessels, esophagus, and trachea are very close to the sternoclavicular joint.

Classification

Anterior Vs Posterior
Subluxation Vs Dislocation
Joint Sprain without instability

Clinical

History of high energy trauma, may be indirect force where a fulcrum effect rotates the clavicle around the costoclavicular ligaments.
Tenderness and swelling around the affected sternoclavicular joint. May be difficult to tell if the dislocation is anterior or posterior (see imaging).
Shoulder is shortened and thrust forward.

Imaging

Radiographs

Several plain radiographic projections have been described, if available it is often best to proceed directly to CT scan

Hobbs view - 90º cephalocaudal view
Heinig view - like swimmers view of C spine
Serendipity view - 40º cephalic tilt

CT scan

CT scan is the best way to image the sternoclavicular joint, 3D CT helps visualise the displacement.

Treatment

It is important to determine the direction of dislocation before attempting treatment, an unreduced anterior dislocation may become asymptomatic and will have very few long term complications. A posterior dislocation needs to be reduced and if remains unstable should be stabilised, long term complications of brachiocephalic vein erosion has been reported.

Anterior dislocation

Attempt closed reduction under GA. Supine with rolled towel between shoulders. Push clavicle head into place and place in sling
If unable to reduce or redislocates/ unstable leave out anteriorly do not attempt open reduction and or stabilisation acutely.

Posterior dislocation

NB have thoracic surgeon available in theatre, cases have been reported where the SC dislocation has been tamponading a vessel injury and on reduction catastrophic bleeding has occurred.
Attempt closed reduction under general anaesthetic, prep and drape the entire chest, pull laterally on the arm, use a sharp pointed towel clip to pull the clavicle lateral and forward.
If following reduction the patient becomes haemodynamically unstable, push clavicle back to tamponade the vessel and involve cardiothoracic surgeon.
If reduced and stable place in figure of 8 bandage
If irreducible or unstable and redislocates perform open reduction and reconstruction/ stabilisation of sternoclavicular ligaments.
Several techniques exist, the primary restraint to anterior and posterior dislocation being the posterior capsule. The most biomechanically superior technique involves a figure of 8 hamstring graft.

Chronic unreduced anterior dislocation

Most are relatively asymptomatic - symptomatic treatment only
Symptomatic anterior dislocation or instability - reduce open and perform ligament reconstruction 75-80% successful

Chronic unreduced posterior dislocation

Perform open reduction and ligament stabilisation as late complications of vessel injury and tracheal and oesophageal fistulas has been reported.

NB Atraumatic anterior or posterior instability in someone with generalized ligamentous laxity is a separate entity/ condition and often does not do well with surgery.
Special considerations
The medial clavicular physis closes at age 18-20, injuries in adolescents and young adults may represent a physeal injury.

Reconstruction/ stabilization of chronic sternoclavicular joint

SEveral surgical technoques have been described to deal with the unstable sternoclavicular joint.

Resection of the sternal head of the clavicle - yields poor results
Transfer of the subclavius tendon
Transfer of the intra-articular disk and ligament into the resected end of the clavicle
Reconstruction of the anterior and posterior aspects of the capsule with use of a figure-of-eight hamstring autograft.
Reconstruction using fascia of sternocleido mastoid

Figure of 8 reconstruction with semitendinosis autograft has been shown to be biomechanically the strongest construct and the technique I use. Spencer

References

Bahk, Michael S., Kuhn, John E., Galatz, Leesa M., Connor, Patrick M., Williams, Gerald R., Jr. Acromioclavicular and Sternoclavicular Injuries and Clavicular, Glenoid, and Scapular Fractures J Bone Joint Surg Am 2009 91: 2492-2510

Spencer EE Jr, Kuhn JE. Biomechanical analysis of reconstructions for sternoclavicular joint instability. J Bone Joint Surg Am. 2004;86:98-105.