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Acromioclavicular Joint Separation

The acromioclavicular (AC) joint is formed at the junction of the clavicle (collar bone), the part of the shoulder blade called the acromion, and the humerus (arm bone). The end of the clavicle meets the acromion, which is a bony extension that curves forward from the upper part of the scapula (shoulder blade). Together they form a socket, into which the round head of the humerus fits. There are also several ligaments associated with the joint, with the most important being the acromioclavicular ligament. This helps to hold the bones in position. An acromioclavicular joint separation, also known as a shoulder separation, occurs when the joint between the clavicle and the acromion is damaged. It is not the same as a dislocated shoulder.

AC separations are graded according to severity and the extent of bone displacement, with grade 1 being a relatively mild strain to the ligaments and capsule of the joint, and grade 6 being torn ligaments and a complete disruption of the bones with the clavicle being displaced downwards and behind part of the scapula. Grade 1 and 2 shoulder separations are by far the most common. Grade 6 separations are rare.

AC Separation Causes:
An injury to this joint is normally the result of landing heavily, or receiving a strong blow, on the shoulder or the elbow. Falling onto an outstretched hand might also cause a shoulder separation. People playing contact sports are obviously at increased risk of this type of injury.

AC Joint Separation Symptoms:
Pain is the main symptom of an injury of this type. The pain is commonly felt at the outer end of the clavicle, nearest the arm, at the moment of impact. Pain may also be felt all over the shoulder, particularly if any movement is attempted, and especially when trying to lift the arms above shoulder height. Later such pain may become more localized to the site of injury. There may be swelling and bruising. If the injury is severe, a noticeable lump, made by the tip of the collarbone, might be visible on the front or top of the shoulder.

AC Joint Separation Diagnosis:
A physical examination and detailed questioning usually provides a clear diagnosis of a shoulder separation. The doctor will also take your pulse to check for damage to blood vessels, test the range of motion of your shoulder and test muscle strength in your shoulder and arm. An x-ray is useful in assessing the extent of the damage.

AC Separation Treatment:
For mild cases of shoulder separation, gentle exercise should be started once the initial pain has lessened, usually after a couple of weeks. Commencing exercise reasonably quickly minimizes the danger of developing shoulder stiffness (frozen shoulder). More serious injuries will take longer to heal. Be guided by your doctor or physiotherapist. A physiotherapist can supervise and advise on suitable exercises to restore normal motion of the joint and to build up muscle strength. Gradual resumption of normal activity as the pain reduces is usually the most effective way to heal.

  • A mild injury can be treated with ice to reduce inflammation. Use ice on the joint for 15 minutes at a time, every 4 hours.
  • Using a sling to restrict movement will ease the pain and allow healing. There are several types of collarbone supports and shoulder supports available.
  • Pain medications such as Tylenol will help, and NSAIDs such as ibuprofen will assist in reducing inflammation.
  • The joint can be taped to provide further restriction of movement and support while it heals. The tape will probably have to stay in place for at least a couple of weeks.
  • A physiotherapist might apply ultrasound or TENS, depending on the severity of the injury.

    Occasionally surgery will be needed for grade 3 separations, as there is some evidence that certain people (athletes, manual laborers) benefit from early surgical intervention. Surgery will almost certainly be necessary for grade 4, 5 and 6 shoulder separations, but these are rare injuries.

    What to look for in a brace to help a shoulder separation injury:
    A comfortable brace, made with breathable fabric, and which provides good support and protection to the shoulder. You might prefer a brace that does not have restrictive straps, which can be uncomfortable.

    AC Separation Rehabilitation Exercises:
    Do not undertake any exercise without prior approval from your health care provider, unless the joint separation was very mild and that you are free from significant pain, usually after 1 to 2 weeks.

    To restore mobility you can try the following:
    While lying on your front on a bench or bed, or bending forward, gently swing the arm backward and forward. Increase the range gradually. Repeat with the arm moving from side to side.
    Front shoulder stretch
    With one forearm resting against a doorframe, carefully turn away from the arm to feel a gentle stretch in the front of the shoulder. There should be no pain. Hold for 10-20 seconds. Repeat 3 times.

    For strengthening:
    External rotation
    With your side to a wall and the upper arm against your side, bend your elbow to a 90 degree angle and place the back of the wrist against the wall. Push gently against the wall with the back of the wrist. Your shoulder should not move. Hold for 10 seconds, release for 5 seconds. Do this 10 times.
    Internal rotation
    Use a wall with a corner for this exercise, or a doorframe. Facing the wall, with your upper arm against your side, bend your elbow to form a 90 degree angle. Place the front of your wrist against the doorframe and press, as though trying to turn your arm towards you. Hold for 10 seconds, release for 5 seconds. Do this 10 times.
    Standing sideways to the wall, straighten the arm and place the back of the wrist and hand against the wall. Push against the wall. Hold for 10 seconds, release for 5 seconds. Do this 10 times.

    AC Joint Separation Prevention:
    Because injuries of this nature are caused by traumatic events, there is not a lot that can be done to prevent them. However, people playing contact sports such as football, hockey or rugby should wear shoulder pads to protect the tip of the shoulder. Maintaining muscle strength and stability of the shoulder may help to prevent injury.