AC Joint Sprain: Causes, Treatment & Recovery Time

The acromioclavicular joint, also known as the AC joint, is that bony bump you notice and feel on top of your shoulder. It enables us to raise our arms over our heads.

It is formed by 2 bones: the clavicle, which is known as the collar bone and the acromion process which is found on the shoulder blade.

What Causes AC Joint Sprain?

1. Trauma

Trauma is a physical, external injury. A fall that involves landing on your shoulder or bumping into a tree while running or skating may cause a sprain to your ligaments.


Trauma can happen in an accident or while participating in a high-intensity sporting activity such as rugby or wrestling.

2. Overuse

Repeatedly doing an activity for a long period of time places a lot of strain on our ligaments. Jobs like farming which involve lifting, digging, and planting (using the shoulders), may cause pain and if adjustments are not made, leading to an AC joint sprain.

An overuse injury, unlike trauma, does not happen immediately but the symptoms may show after a period of time.


  1. Pain at the top of the shoulder
  2. Swelling at the top of the shoulder
  3. Limitation while moving the shoulder joint
  4. Weakness of the shoulder muscles
  5. A prominent bump may be seen at the top of the shoulder joint. This could be the clavicle being separated from the acromion process on the scapula.

Diagnostic Tests

An X-ray is usually carried out to rule out fractures or dislocations that may happen at the shoulder joint and also pinpoint the cause of pain at the shoulder joint.

An MRI will show the severity of the ligament injury and allow your doctor or physiotherapist to carry out the treatment based on the injury seen.



1. RICE Protocol

The RICE protocol is the go-to treatment for any ligament injury. This treatment is usually done within the first 72 hours of injury. However, depending on the signs you have, your physiotherapist or doctor may suggest that some parts of the RICE treatment should continue for more than 72 hours.

The RICE treatment stands for:

  • R – Rest
  • I – Ice
  • C – Compression
  • E – Elevation


An arm sling, shoulder support or taping may be recommended to reduce the amount of movement at the shoulder. This prevents re-injury of the joint and helps speed up the healing process. The splint may be worn for 4 weeks depending on what your doctor or physiotherapist advises.



Ice helps to reduce swelling and can be used at home. The easiest way to use ice at home is to put crushed or cubed ice in a damp towel and place it on your shoulder joint for 15 minutes. This can be done every four hours for the first 72 hours.

Compression And Elevation

This may not be necessary for the AC joint but if there is swelling, an elastic bandage can be wrapped around the joint, but not too tight.

Elevation may be done while lying down on your back by placing a pillow under your shoulder or using an arm sling.

2. Pain Killers

Over-the-counter medications are taken to relieve pain. Some of these medications are known as Non-Steroidal Anti Inflammatory Drugs (NSAID). Examples of this class of drugs are ibuprofen, diclofenac, and ketoprofen.

3. Physiotherapy

Physiotherapy plays a major role in rehabilitating injured parts of the body. The main goal of physiotherapy is to return you to how you were before the injury.

A physiotherapist will draw up treatment goals and plans with you and as you achieve your goals, they add more goals when they feel that you can handle them.

Physiotherapists prescribe exercises and teach some lifestyle modifications like how you should sleep without causing more harm to the injured joint.

4. Surgery

Surgery is usually recommended for grade 3 ligament injury. The surgery that is most commonly recommended is the ligament reconstruction surgery. In this surgical procedure, the injured ligaments are usually replaced by tendons from other parts of the body.

5. Exercises

As the injury heals, exercises will be included in your treatment plan to strengthen the muscles surrounding the joint. At the initial stage, exercises with assistance are encouraged before strengthening exercises so the affected shoulder is not overworked. Exercises are usually introduced into treatment 1- 3 weeks after injury depending on the severity.

Recovery Time

The healing process depends on the severity of the injury and how soon the injury is attended to by your doctor. Seeking medical treatment early helps to ensure a speedy healing process.

For a grade 1 injury, it takes about 6 weeks for the ligaments to heal.

For a grade 2 injury, it may take 6-12 weeks.

For a grade 3 injury, which usually involves surgery, it may take about 3 months.

Preventing AC Sprain

  • Reduce overusing your shoulders. Take stretch breaks when you are doing activities over your head.
  • Try to avoid any direct force to your shoulder if you can.
  • Strengthen your muscles in order to avoid re-injury to the ligament. Seeing your doctor and physiotherapist on a regular basis will ensure the AC joint remains intact.


An acromioclavicular joint sprain is an injury to the ligaments that maintain the joint and keep it in place. Quick intervention can save your shoulder joint and speed up recovery. Waiting before seeing a medical professional can lead to a lot of complications.

Latest posts by Adekanmi Lipede, M.Sc, MPH (see all)
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