Biomechanics and treatment of acromioclavicular and sternoclavicular joint injuries.

Acromioclavicular (AC) joint injuries are more common than sternoclavicular (SC) joint injuries. There is a spectrum of AC joint traumatic injuries that ranges from a ligament sprain to a complete dislocation. The majority of AC joint injuries are successfully treated non-operatively with a period of sling immobilisation followed by progressive physical therapy and shoulder range of motion exercises. In patients who have symptomatic AC joint injuries that are recalcitrant to non-operative treatment there exists a variety of surgical treatment options to reconstruct and stabilise the joint. The SC joint, like the AC joint, can suffer a spectrum of ligamentous injuries; however, when it comes to dislocation it can only dislocate anteriorly or posteriorly. Anterior dislocations are often successfully treated with closed reduction. Posterior dislocations have significant clinical implications because of the proximity of surrounding vessels and nerves. Any attempt at reduction of a posterior dislocation requires the presence of a cardiothoracic surgeon. The majority of AC and SC joint injuries typically result in ligamentous sprain and heal uneventfully with a period of immobilisation. If, however, patients remain symptomatic after non-operative treatment or have a dislocated joint, there are reduction manoeuvres and surgical techniques that allow joint stabilisation.