AC Joint Injury: Causes, Symptoms, And How To Treat It


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Publish date

July 18, 2021



AC joint injury is a kind of injury involving shoulder separation. It often happens when the acromioclavicular (AC) joint or rotator experienced a cuff from a fall or from playing sports. A sports injury can happen unexpectedly. However, you can prevent such injuries by wearing proper protective equipment, such as mouth guards. You can click here to find out about mouth guards.

Meanwhile, this article will discuss how physical therapy can address this type of injury. But before that, we will talk about AC joint injury first, its causes, symptoms, and then treatment will be the last.


Acromioclavicular (AC) Joint Injury

The acromioclavicular joint involves the cap of the shoulder (acromion) and the collar bone (clavicle). Meanwhile, strong ligaments are holding them together. In actuality, the acromioclavicular joint is strong. However, its location makes it prone to trauma or injury.

Additionally, an AC joint injury has various types. Each type depends on how much rip the AC joint or coracoclavicular (CC) ligaments incurred. Let us briefly discuss each type of acromioclavicular joint injury.

  • I: The AC ligament has a partial tear, while the coracoclavicular ligaments have no damage.
  • II: You have a completely torn AC ligament, while the CC ligament has little to no damage.
  • III: In this case, you have entirely torn both the AC and CC ligaments. In effect, the collarbone separates from the end of the shoulder blade.
  • IV, V, VI: Rare cases of joint injuries, but the most severe. The treatment will require surgery.


Causes of Shoulder Separation or AC Joint Injuries

AC joint injury or shoulder separation.The primary causes of shoulder separation or AC joint injuries are the following:

  1. a fracture in the shoulder
  2. shoulder dislocation
  3. outstretched arm
  4. a family history of arthritis

Although arthritis primarily affects older adults, children can still develop arthritis due to the above conditions. Contact sports are one of the typical sources of these kinds of injuries.

Other Potential Causes


Symptoms to Know You Have AC Joint Injuries

When you have AC joint injury, you are most likely to experience the following conditions.

  • General shoulder pain and swelling
  • Swelling and tenderness in the AC joint
  • Loss of shoulder strength
  • Bump on top of the shoulder
  • Pain when lying on the affected shoulder
  • Loss of range of motion in the affected shoulder
  • A popping sound
  • Inability or discomfort when performing daily activities

If you felt any of these symptoms, it would be best to receive treatment for the condition. If you have incurred an injury from playing contact sports, sports medicine can help you manage your injury.

Sports medicine is the branch of medicine that helps people improve performance, achieve quick recovery from injury, and prevent future injuries. Healthcare workers in this field help various kinds of people and not athletes only.


Shoulder Separation Diagnosis

Physical therapists will require you a shoulder exam and conduct a complete evaluation. The evaluation will include an interview about your health history. As the discussion goes on, it will become more particular to your shoulder injury.

The physical therapist has a high chance of asking the following questions to you. Your answers will also add to their consideration for your treatment.

  • A physical therapist conducting his diagnosis with his female patient.How did the injury happen?
  • What did you do to take care of the condition?
  • Have you already seen a health care provider?
  • Did you have X-rays or MRIs? What are the results?
  • What symptoms do you experience? How did they affect your daily activities?
  • Do you feel joint pain? Where is the location? What is the intensity of the pain?

There could be more questions your physical therapist may ask you during your evaluation. They will prepare a treatment plan for you according to your specific needs. Once settled, your treatment program will start.


How Can Physical Therapy Help?

The treatment depends on how severe your joint separation is. But one of the most common treatments applicable is physical therapy for this kind of sports injury.

Physical therapy involves the following as part of the treatment program for patients.

  1. Educating patients: The physical therapist will provide details about the AC joint and shoulder injury. Additionally, they will help you identify the external factors that cause pain. The therapist will also discuss with you the set of exercises and activities that can improve your condition.
  2. Pain management: The initial remedy they will try on your joint injury is applying an ice pack. It can numb the affected part and relieve pain from it. Physical therapists are very familiar with various pain management methods.
  3. Range of motion exercises: These exercises will help you decrease the stress on the shoulder. The self-stretching methods can also lower the tension and restore the normal motion of joints.
  4. Manual therapy: It involves the movement of muscles and joints. Your physical therapist will guide your injured shoulder to make it less stressful.
  5. Muscle strength: It includes using resistance machines from the clinic and exercises that you can do at home. The exercise program will depend on diagnosis, age, and condition.
  6. Functional training: This kind of training will help patients resume their demanding activities more safely. It involves more movement of the injured shoulder blade, joint, and arm. A few activities related to this are throwing, swinging a racket, lifting objects overhead, and other daily activities.

Physical therapy is an excellent way to address AC joint injury. But then again, you might also need to take anti-inflammatory make the pain and swelling subside. Furthermore, if physical therapy and other treatment procedures don’t work, surgery will be necessary.


How Long is the Recovery Period?

In actuality, the length of recovery depends on the severity of the AC joint injury. It depends on how severe the tear of the ligaments is. In minor injuries of the AC joint, you would be able to return to your activities three days to two weeks. However, if the condition is severe, it may take six weeks or more to recover fully.



You cannot see when injuries are coming. However, you can do something to lower the risk of their occurrence. Especially when playing extreme or contact sports it is advisable to protect your mouth and your head with special equipment.



Physical Therapy Guide to Acromioclavicular Joint Injuries,, March 21, 2021,

Acromioclavicular (AC) Joint Injury,, Accessed July 13, 2021,

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