Acromioclavicular Joint (AC) Separation
The shoulder is a ball-and-socket joint and is the most flexible joint in our body. It is made up of three bones; the upper arm bone (humerus), the shoulder blade (scapula) and the collarbone (clavicle). The end of the scapula is called the acromion, and the joint between the acromion and the collarbone (clavicle) is called the acromioclavicular (AC) joint.
How Does an AC Joint Separation Occur?
An AC joint separation is a very common injury among those who are physically active. It occurs when the collarbone (clavicle) separates from the acromion at the end of the scapula (shoulder blade). Most AC joint separations can be attributed to a sudden, traumatic event. Common causes include a direct blow to the shoulder, as seen in sports such as football, rugby and hockey. They are also often seen as a result of a fall onto an outstretched hand, as is seen in a fall from a horse or when a cyclist falls over the handlebars of their bike.
Grades of Injury and Symptoms
Acromioclavicular joint separations are graded from Grade I to Grade VI according to the severity of injury, involvement of other structures and the extent of damage to those structures. Grades I-III are the most common.
Diagnosis: Your physician will ask a detailed history, paying close attention to how the injury occurred and how you landed. He will then do a thorough clinical examination of the shoulder area. Your physician will examine the AC joint and will gently feel the bones and soft tissue around the joint and between the clavicle and acromion. S/he will assess these areas for tenderness, a bump on the top of the shoulder and any sign of instability. An x-ray will confirm the diagnosis of an AC joint separation and also show any fractures in the bone.
Treatment: Most Grade I, II and III separations are successfully treated with non-operative treatment. Initial treatment of Grade I, II and III AC joint separations consist of:
- Ice placed on the joint for 15 minutes every four hours to reduce pain and swelling
- Rest the AC joint by using a sling until pain has subsided. Your physician will determine when you may begin simple range of motion exercises. A sling is often indicated for 2-3 weeks following injury.
- Non-steroidal anti-inflammatory medications such as Advil or Aleve may help to control pain and decrease inflammation
- Sling immobilization may be helpful for initial pain control your physician will advise you when it is appropriate to begin a rehab program to restore motion and strength. Most patients will heal within 1-3 months without surgery. Return to activity and sport is dependent on motion, pain and healing.
Surgical Treatment: Surgery may be indicated for AC separations that do not respond well to non-operative treatment and for Grade III and above injuries. Surgery is sometimes recommended for the treatment of Grade III and Grade V separations for athletes who participate in sports requiring overhead throwing and in laborers whose jobs require heavy overhead work. There are several operative techniques that can be utilized to stabilize a separated AC joint. These procedures attempt to reconstruct the coracoclavicular ligaments and hold the clavicle in position while the reconstructed ligaments heal. If surgery is indicated for the treatment of your injury, your physician will discuss in detail the specific procedure he intends to perform, the risks and potential complications.
