The AC Joint (Shoulder) Separation

The AC Joint (Shoulder) Separation

AC Joint (Shoulder Separation) - It Can Happen to You

It's the weekend and you're out for an afternoon cycle. The air is warm, the sky is blue, and you are cruising down a clear mountain road. Life couldn't get much better.

Until you get buzzed by some teens joyriding at 75 mph in dad's M5, go over the handlebars, and land on your shoulder. Your fancy road bike is ok, and your helmet did its job and protected your brain. Sounds like a win.

But when you stretch your arm, your shoulder is tender and painful. In this scenario, chances are you've suffered an ACL Joint Separation.

What is the AC Joint Separation?

So what's this mean? When we talk about the AC Joint Separation, we are referring to a shoulder separation. Most often, we see this injury in football and other contact sports. 

How is an AC Joint Separation Caused?

The AC Joint separation is often caused by a direct blow to the shoulder. For instance, when a football player falls and an opponent lands upon the shoulder. With all the body-checking and slamming opponents into the boards, hockey is also rife with this injury.

Do AC Joint Separations Need Surgery?


Ok, so you separated your shoulder getting checked at the rec league hockey game after delivering a pass Gretzky would be proud of. Your center rammed home the goal, but now you are paying the price. Do you need surgery?

Well, that depends on how serious the ac joint separation is. We use three grades of classification to describe the severity of this injury. What are they? I'm glad you asked.

Grade 1 AC Joint Separation

A grade one AC Joint Separation is a common injury, resulting in a slight displacement of the joint. Here we see a slight stretching or partial tear of the "acromioclavicular ligament".

Symptoms of a grade 1 ac joint separation:

  • Joint tenderness
  • Joint brusing
  • Minor pain

Grade 2 AC Joint Separation

A partial dislocation of the joint. In this case, we also have an acromiioclavicular ligaments that is completely torn.

Symptoms of a grade 2 AC Joint Separation

  • Pain around the joint that can be severe
  • The clavicle may move when pushed
  • Swelling
  • More pain when the arm moves or when you touch the ligaments

Grade 3 AC Joint Separation

The grade 3 is a complete separation of the joint. Here we see a torn joint capsule, acromioclavicular ligament, and coracoclavicular ligament. This is easy to diagnose due to the bump on the shoulder cused by the upraised clavicle.

Symptoms of a Grade 3 AC Joint Separation

  • The elbow may need extra support (to be held) to avoid pain
  • Pain upon moving the arm
  • More pain around the joint
  • Swelling
  • "Popping" of the joint when moving it
  • As the joint moves, a popping sound may occur.
  • A bump on top of the shoulder
  • Instability in the AC joint

How to Treat the AC Joint Separation Without Surgery


Here's the good news. We can treat AC joint separations in grades 1 - 3 using the following:

  • Icing to reduce pain and swelling
  • Resting the injury (the higher the severity, the more rest required)
  • Using medications to ease inflammation and pain
  • Employing basic exercises at the recommendation of your physical therapist

Grade 4 - 6 AC Joint Separation

We don't often see this level of AC joint separation. When we do, we have to treat the injury surgically.

What's The Difference Between a Shoulder Separation and a Shoulder Dislocation?

Shoulder Dislocations are when the ball pops out of the socket. 90% of the time the ball comes out the front of the shoulder and only 10% of the time does it come out the back.

Usually this happens when we have the arm out overhead and behind the body. Much like the cocking phase of throwing. In this position a forceful external force pushing the lower arm even more rotated will cause the shoulder to lever out of the socket.

Shoulder Separations, on the other hand, have nothing to do with the ball and socket joint. The point where the clavicle comes into the end of the scapula, called the acromion, gets “separated” by tearing the ligaments attaching these two. Typically these do not require surgery. But the may, depending upon the degree of separation.

Shoulder Disclocations and Age

The risk of dislocating the shoulder a second time is related to the age of the athlete when he/she first dislocates. It can also relate and the activities they like to participate in. Once a shoulder dislocates a second time, it gets easier and easier for it to pop out again. In this case, we usually need to fix it with surgery.

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