Acromioclavicular Joint Injury
The acromioclavicular (AC) joint is the joint between the collarbone (clavicle) and acromial process of the shoulder blade (scapula). Injuries to this joint are usually from a direct trauma to the shoulder. This typically occurs when the top of the shoulder is impacted from a fall directly onto the shoulder or by an impact from being tackled or an object falling on the shoulder. When this occurs there is damage to the joint capsule between at the AC joint as well as two ligaments called the coracoclavicular ligaments. These ligaments attach to the undersurface of the clavicle (collar bone) and to the superior surface of the coracoid process. This is a finger-like projection off of the front of the shoulder blade (scapula). These injuries are graded in severity from a Grade I injury to a Grade VI injury. Grade I, II and III injuries are usually treated non-operatively. Grade IV, V and VI injuries usually require operative treatment.

Injuries to the AC joint usually cause pain in the area as well as swelling. With higher grade injuries, there can also be noted deformity of the shoulder with prominence of the end of the collarbone (clavicle).


Grade I, II and III injuries are treated non-operatively. This includes observation, rest and anti-inflammatory medications. Avoidance of activities that may cause a repeat trauma to the area may also be necessary for a period of time as this may worsen the injury to a higher grade injury. Occasionally, if symptoms do not improve with non-operative treatment operative treatment is necessary.

There are many techniques available for the treatment of AC joint injuries. These can be performed arthroscopically and open. The choice of an arthroscopic or open surgery depends on the grade of the injury as well as the acuteness or chronicity of the injury. This is typically performed as an outpatient surgery.