Acromioclavicular Joint Injuries

The notes on this page are written as a source of information to both patients and health professionals. It is a general overview and its content should not be seen as direct medical advice. Further information regarding diagnosis and treatment specific to your condition can be made via a consultation with Dr Amaranath.

Anatomy of the Acromioclavicular Joint

The acromioclavicular joint (ACJ) is a synovial (fluid forming) joint formed by the lateral end of the clavicle and the acromion. It is surrounded by a capsule that thickens to form capsular ligaments which help support it through a range of motion. It enables the scapula to move along the thorax and thereby helps shoulder and arm function. This is crucial in movements such as throwing, lifting and swimming. 

The coracoclavicular (CC) ligaments are made up of two ligaments called the conoid and trapezoid. These attach from the coracoid process to the lateral end of the clavicle and are the primary stabilisers of the ACJ.

What is an ACJ injury?

Commonly an ACJ injury results in the disruption of the capsule and/or CC ligaments. This causes instability of the ACJ and leads to subluxation/dislocation of the lateral end of the clavicle in relation to the acromion. The injuries can be classified (Rockwood classification) based on the degree and position of displacement of the lateral end of the clavicle.

What are the common causes?

Commonly, it caused by a direct blow to the outside of the shoulder which causes disruption of the capsule or CC ligaments.

What are the preferred Investigations/Imaging?

  1. Plain X-Ray of the shoulder - This should include an Anterior/Posterior, Lateral, Axillary view and Zanca view (where the X-ray beam is taken from an inferior position and helps determine the superior displacement of the clavicle).

  2. CT shoulder – This may be indicated if there is any suggestion of an associated fracture of the shoulder girdle. 

ACJ injury Orthopeadic surgery Sydney

What are the treatment options?

  1. Non-operative – In cases of minor injury to the capsular ligaments or mild displacement of the ACJ non-operative measures can be initiated. These include sling, pain control and a graduated physiotherapy programme. 

  2. Surgical ACJ stabilisation– In cases where there is significant displacement and instability of the ACJ due to disruption of the CC ligaments, then surgery would be recommended. This commonly involves maintaining a reduction of the lateral end of the clavicle to restore the ACJ and allow the CC ligaments to heal. This is achieved by using strong sutures that are passed through the coracoid process and lateral end of clavicle in a suspensory technique.

What does the rehabilitation/recovery involve?

To find out more about rehabilitation and recovery after shoulder surgery please see our Rehabilitation Protocols here.