Treatment of AC Joint Shoulder Sprains

What is the AC Joint?

The AC Joint, formally known as the Acromioclavicular Joint, is a synovial joint located near the top of the shoulder. In the medical field, most joints are named by the bones that articulate at that particular joint. In this case, the Acromioclavicular Joint is formed by where the Acromion bone (the top part of the shoulder blade) meets the Clavicle (collarbone). If you’re unsure as to where these two bones are located, then here is a diagram to help you out further.

The primary function of the AC Joint is:

1. To allow for increased range of motion as the arm is raised overhead
2. To provide transmission of forces from the arm into the clavicle
   • i.e. In the case that you fall onto an outstretched arm, elbow, or shoulder

As you can see in the picture above, the AC Joint has a joint capsule and several ligaments that help to stabilize the joint when the shoulder and arm perform movements.

The AC Joint consists of 3 supporting ligaments:

1. Trapezoid Ligament
2. Conoid Ligament
3. Coracoacromial Ligament

What is an AC Joint Sprain?

AC Joint sprains occur when there is a sudden force applied through the AC Joint ligaments and joint capsule that cause excessive stretching and damage to these connective tissues. Similar to most other ligamentous sprains in the body, there are different grades of severity.

The 3 basic AC Joint Sprain grades are:

1. Grade 1
   • Non-displaced AC Joint (very common and most people with these do not even come in for physical therapy)
2. Grade 2
   • Partially dislocated AC Joint (pretty common and suitable for physical therapy)
3. Grade 3
   • Completely dislocated AC Joint, also known as AC Joint Shoulder Separations (very bad and will likely require surgery)

Common Causes of AC Joint Sprains

AC Joint sprains typically require some form of blunt force trauma applied to the arm or shoulder.

Common causes of AC Joint sprains include:

1. Falling onto an outstretched arm
2. Falling onto an elbow
3. Blunt force trauma to the shoulder 
   
   • Impact sports such as ice hockey and American football increase the risk of suffering an AC Joint sprain

Symptoms of an AC Joint Sprain

Initial symptoms of an AC Joint sprain will include:

1. Shoulder pain originating from the AC Joint located at the top of the shoulder
   • Tenderness to palpation at the joint will be present
2. A step-sign will be present with a Grade 2 AC Joint sprain or higher
   • There will be a noticeable shift or separation in the bones on either side of the joint. This can be felt with your fingers on the joint and seen with the naked eye. X-rays can also easily confirm the presence of a step-sign as seen in the image below.
3. Pain originating from the top of the shoulder with active arm elevation
4. Weakness with arm elevation

Treatment Options

Treatment options for AC Joint sprains will typically depend on the severity (grade) of the injury.

If the individual has a grade 1 or 2 sprain, then they will have pain with actively raising the arm out to the side or overhead, however, they will benefit from physical therapy treatment techniques and exercises.

If the individual has suffered a grade 3 complete separation that is seen in the x-ray image above, that person would likely need to see a medical professional or orthopedic surgeon for a consultation to discuss if he or she would need a ligament reconstruction surgery. AC Joint separations of grade 3 simply depend on how much displacement there is between the two joint surfaces as they might respond well to physical therapy AC Joint sprain treatment if they still have a couple of the ligaments stabilizing the joint.

Initial Treatment After an AC Joint Sprain/Separation

If you’ve been unfortunate enough to have just suffered an AC Joint sprain, follow these steps:

1. Wear a shoulder sling (sprain grades 2-3) for 2-4 weeks
   • Shoulder slings are important to wear throughout the day initially after a sprain to allow for the injured (stretched/torn) ligaments to begin to heal in an approximated position. If you don’t wear a sling, the ligaments will heal in a stretched position as the arm weight is constantly pulling down on AC Joint ligaments.
     

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2. Tape the AC Joint for extra support
   • Use Leukotape and Cover Roll in a cross technique to help stabilize the AC Joint when performing physical therapy exercises out of the sling for the first 2-4 weeks, then continue using the tape as needed when exercising for up to 3 months after the injury.
   • Watch how to tape the AC Joint in my instructional video at the bottom of this article.
     

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     Leukotape

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     • PROTECTS SKIN FROM SCRATCHES AND RUBBING

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3. Use Cryotherapy as needed for pain relief
   • Use a quality gel cold pack for 10-15 minutes on the shoulder as needed.
     

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4. DO NOT lift or carry heavy objects with the injured arm for at least 8 weeks while the ligaments are healing
   • Let pain be your guide. If it hurts the AC Joint when doing something with the arm, try to not do that activity or at least modify the activity to reduce the stress on the joint as much as possible.

How Long Does it Take for an AC Joint Sprain to Heal?

Ligamentous healing can vary from 4 weeks for mild sprains all the way up to several months for more severe grade 3 sprains. AC Joint sprains, in particular, can be quite frustrating because they can significantly limit someone’s daily activities that involve reaching, carrying, and lifting objects.

It is important to remember that ligament sprains are notoriously slow healers and that is imperative to protect the AC Joint ligaments with a shoulder sling and/or taping technique to promote an optimal outcome in the end.