Sternoclavicular Joint Dislocation

The sternoclavicular joint is the only bony link between the arm and the axial skeleton. The costoclavicular ligament is its main restraint, supported by the capsule and interclavicular ligament and an articular disc. Dislocation is rare (under 3% of shoulder girdle injuries). Mechanisms are a road traffic collision with a direct blow to the front of the chest or compression of the shoulder, and contact sport.

Direction and risk:

• Anterior (about 90%): usually benign.
• Posterior (retrosternal): uncommon but dangerous. The clavicle can compress the trachea, oesophagus, brachiocephalic vessels, subclavian vessels, carotid artery, and the vagus and phrenic nerves.

In patients under 25 the medial clavicular physis is still open (it fuses at about 23 to 25 years), so most injuries are physeal fractures that mimic dislocation. Complications are airway obstruction, vascular injury (with a high mortality), pneumothorax, recurrent instability and arthritis.

• Pain and swelling over the joint, worse with arm movement or lying flat
• Anterior: a visible prominent medial clavicle
• Posterior: a palpable depression, and signs of mediastinal compression (dyspnoea, stridor, dysphagia, voice change, neck or arm venous congestion, reduced arm pulse)
• Red flags: any airway or swallowing symptoms, haemodynamic instability, haemoptysis, arm ischemia, and a high energy mechanism

• Clinical assessment with an airway and neurovascular check.
• Radiographs are unreliable. A serendipity view (40 degrees cephalic tilt) may help.
• CT chest with IV contrast is the investigation of choice. It shows the direction of displacement, physeal fracture and mediastinal involvement.
• CT angiography when vascular injury is suspected.
• MRI in children to define the physis.

Differentials: medial clavicle fracture, sternoclavicular infection, osteoarthritis, condensing osteitis, Tietze syndrome.

Anterior dislocation or sprain:

• Sling for 2 to 6 weeks, ice, paracetamol 1 g orally every 6 hours, ibuprofen 400 mg orally every 8 hours with food for up to 7 days.
• Closed reduction is rarely maintained, and residual anterior prominence is accepted.
• Surgery for chronic symptomatic instability: reconstruction with a figure-of-eight semitendinosus graft through tunnels in the clavicle and manubrium. Avoid pins and wires, which migrate.

Posterior dislocation:

• Resuscitate and secure the airway. CT first unless unstable.
• Closed reduction under general anaesthesia within 48 hours to 10 days, with a thoracic or vascular surgeon in the theatre. Technique: supine with a bolster between the scapulae, traction on the abducted arm with extension, and if needed a sterile towel clip on the medial clavicle to lift it anteriorly.
• Open reduction if closed reduction fails, with ligament reconstruction.
• Cefazolin 2 g IV before incision.
• Postoperative: sling for 4 to 6 weeks, no overhead lifting for 12 weeks.

Physeal fracture in children and adolescents: reduction (closed for posterior), suture fixation if unstable. Remodelling is good. Ibuprofen 10 mg/kg orally every 8 hours and paracetamol 15 mg/kg orally every 6 hours for up to 7 days. Cefazolin 30 mg/kg IV (maximum 2 g).

Complications: vascular or tracheal injury, hardware migration, infection, redislocation, and arthritis.

Follow up at 1 week, 6 weeks and 3 months. Counsel on avoiding contact sport for 3 to 6 months.