Arthritis and AC Joint Dislocation

The main joint of the shoulder is a ball-and-socket joint formed by the glenoid socket and the humeral head. Most people think of this when they think of the shoulder joint. In fact, several joints make up the shoulder. The AC joint is a small joint directly on the top part of the shoulder and is the junction of the outer end of the clavicle (collarbone) and the acromion (upper part of the shoulder blade). A shoulder separation occurs when the acromion is forced away from the collarbone. Typically, it is forced up above the acromion resulting in a bony prominence on top of the shoulder. This usually happens as a result of a traumatic injury to the outer part of the shoulder. Common forms of this injury occurring in athletes include a hockey player going shoulder-first into the boards or a football player landing directly on the ground shoulder-first, often with another player on top, driving him into the ground. Non-athletic mechanisms can include falls onto the shoulder (often over the handlebars of a bike) or when trying to break a door down with one’s shoulder. The collarbone is held to the shoulder blade by two sets of ligaments, which often injured with a shoulder separation. If these ligaments are injured, the result is usually a higher grade or severity separation

Common symptoms of AC separation include:

• Pain caused by a shoulder injury
• Prominence or deformity on the top of the shoulder
• Painful grinding on the top of the shoulder with movement
• Pain or weakness with vigorous overhead activities Typically, in lower grade injuries, these symptoms get better without surgery, except the prominence on top of the shoulder.

Treatment

For lower-grade injuries, nonsurgical treatment is usually successful. Time, rest and gradual rehabilitation typically result in a shoulder free of pain and functional limitations. The recovery time varies from patient to patient, but full recovery typically occurs within 6-12 weeks. A return to contact sports may require more recovery time to reduce the risk of re-injury. Some degree of protrusion at the AC joint often remains but does not require surgery. In higher-grade injuries or those that fail to respond to non-surgical management, surgery may be needed.

Nonsurgical Treatment

Activity modification includes making some temporary changes in your lifestyle and avoiding activities that aggravate your symptoms.

Anti-inflammatory medicine like aspirin and ibuprofen reduce pain and swelling.

Home exercise/physical therapy can strengthen your shoulder muscles and improve shoulder stability.