A “separated shoulder” is an injury to the acromioclavicular (AC) joint. The terminology can be confusing as there is the actual ball and socket joint of the shoulder (or glenohumeral joint). Rather, there is disruption of the AC joint, which is where the collarbone (or clavicle) and the highest point of the shoulder blade (the acromion) meet. In AC joint injuries, the ligaments that hold these 2 bones aligned are torn to varying degrees.

AC joint injuries represent nearly 50% of all athletic shoulder injuries. They usually result from a fall onto the tip of the shoulder.  I commonly see it in snowboarders, skiers and mountain bikers. I suffered one myself when I fell off my mountain bike some years ago.

Following these injuries, patients experience pain, swelling and notice a bump on top of their shoulder which varies in size based on the severity of the injury. Orthopedists classify these AC joint injuries as Type 1-6 with Type 1 being the least severe. Unlike most ligamentous injuries, such as an ACL or MCL tear of the knee, orthopedists depend primarily on xray findings and less so on physical exam findings to determine what type of AC joint injury a patient has sustained. Type 1 and 2 injuries are less severe disruptions of the AC joint and are treated without surgery. A sling for 1-2 weeks is recommended to help relieve stress on the injured ligaments and help decrease pain.  Following this, physical therapy is started to restore shoulder range of motion and strength. Patients may be left with a small bump over the end of their collarbone for the rest of their life, but most go on to regain full shoulder range of motion and are able to resume all activities without pain. A small percentage of these patients can have persistent pain that later necessitates surgery. Type 4,5 and 6 injuries are high energy injuries with severe displacement of the end of the collar bone in relationship to the shoulder blade. There is disruption of not only the AC joint ligaments but also the coracoclavicular (CC) ligaments.  For these types of injuries, surgery is recommended. Without surgery, most patients experience chronic pain and shoulder weakness.

In Type 3 injuries, the AC joint is dislocated with the collarbone being 100% displaced superiorly in relationship to the acromion. The AC joint can be reduced back into alignment by placing an upward force on the arm. Treatment of Type 3 injuries are the most controversial with some sports medicine orthopedists recommending immediate surgery while others recommending a wait and see approach. In my own practice, I used to recommend a wait and see approach for most patients except those who were overhead athletes or those who do a lot of overhead work (ie. a capenter). However, the arthroscopic methods and the implants used to fix these injuries have gotten so much better that I honestly fix more acute Type 3’s than I used to. However, treatment depends on the patient’s age and activity level. Many patients do well without surgery. I do recommend immediate surgery for patients with Type 3 injuries if they are younger, do a lot of overhead work (ie carpentry) or are an overhead athletes (ie. a tennis player) , as without surgery, they may experience chronic pain and lose some strength and endurance.

The surgical treatment for higher grade AC joint injuries has improved significantly over the past few years. Although these injuries have been treated arthroscopically for some time, the implants and materials used to fix injuries are much stronger than the implants and materials that were available even a few years ago, which had a fairly high failure rate.

These injuries are best treated soon after the injury so if you have one of these injuries get in and see your orthopedist within the first week or two. If patients present months or years later with a painful Type 3-6 AC joint injury, the surgery is more involved the surgical results are not as good. Unfortunately, the rehab after these injuries is quite long with patients in a sling for 6-8 weeks and activities limited for 3-4 months.