AC (acromioclavicular) joint injury Ngā whara ki te hononga pokohiwi-manumanu
Your AC (acromioclavicular) joint is the joint at the outer end of your collar bone (clavicle). Injuries to this joint usually happen because you have fallen directly onto your shoulder. An injured AC joint can range from mild to severe.
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Symptoms of AC joint injuries
You may feel a lot of pain at the top of your shoulder, which is made worse when you try to:
- lift anything heavy
- lift your arm above your head
- move your arm across your body.
It may be hard to move your arm at all. You may also see:
- swelling, with or without bruising
- a hard lump on the top of your shoulder — this shows that your collar bone has moved. This happens in more severe injuries.
If your injury is not too bad, you will need to rest and exercise to help your joint heal. If your injury is more severe, you may need surgery.
Diagnosing AC joint injuries
Your healthcare provider or physiotherapist can diagnose a dislocated AC joint by listening to what happened and examining your shoulder. Depending on your injury and the symptoms, you may need an x-ray.
Self care for an AC joint injury
There are some things you can do to help your recovery, whether or not you are having surgery.
- If you smoke, stop smoking. Continuing to smoke will slow down how quickly you heal.
- Do not do any heavy lifting, as this will only increase your pain and slow your recovery. You will probably need some time off work to allow your shoulder to recover.
- Take regular pain relief. The best pain relief is paracetamol. Take 2 tablets every 4 hours but no more than 8 tablets in 24 hours. If you are still in a lot of pain, contact your healthcare provider.
- If you are having difficulty sleeping, try sleeping in a recliner chair or packing pillows around you.
- Hold an ice pack against your shoulder for 15 minutes at a time to decrease pain and swelling in the first 24 to 48 hours.
- Keep your hand, wrist and elbow moving to stop them becoming stiff. As your pain gets better, start doing shoulder shrug and shoulder blade squeeze exercises. You can also do shoulder adduction and abduction, and flexion and extension exercises.
Exercises for an AC joint injury (internal link)
If any of these exercises make your pain worse, stop doing them and call your healthcare provider or physiotherapist. You should also see your healthcare provider if you are not starting to get better within a week of doing these exercises.
Treating AC joint injuries
AC joint injuries are usually treated by resting your arm and shoulder in a sling until the pain starts to get better.
You should keep your arm in a sling at a right angle. This puts the least stress on the injured part of your shoulder. At first, wear the sling under your clothes, as this will act like a splint for your arm and keep your shoulder still. Do not drive while your arm is in a sling.
If you have a simple injury, physiotherapy should make it a bit stronger to get you back to your normal activities and sport.
If your injury is more severe or if a simple injury does not get better with resting and physiotherapy, you may need surgery to help the injury heal.
If you need surgery, your doctor or physiotherapist will refer you to an orthopaedic (bone) surgeon. What operation you have, the risks and benefits and how long it will take you to get better will depend on the details of your injury. Your surgeon will talk to you about this.
Surgery usually involves spending one night in hospital. Afterwards, your arm will be in a sling for 6 weeks — you will not be able to drive during this time. You will also have a course of physiotherapy to strengthen your shoulder and get it moving again.
You may need some time off work. How long will depend on the type of injury and the type of work you do. Your healthcare provider or physiotherapist will let you know if you can work with your injury.
While you are recovering, it is best not to lift or carry anything on the injured side. For the 6 weeks your arm is in a sling you should not lift anything at all — not even a cup of tea or coffee. After that you will gradually be able to increase what you can lift and carry. But you should not lift anything heavy until you have normal movement back in your arm. Your surgeon will let you know when it is safe to start lifting.
Getting help for an AC joint injury
If you have any concerns about how you are healing or have a lot of pain, see your healthcare provider.
If your arm feels stiff after the pain has gone and you are no longer wearing a sling, see a physiotherapist who can help you with exercises and help strengthen your arm.
Exercises for an AC joint injury
Shoulder shrugs
- Sit or stand in a relaxed position.
- Shrug your shoulders up to your ears and hold for 3 seconds.
- Lower them down as far as you can go.
- Repeat this 10 times.
Shoulder blade squeeze
- Sitting tall, move your shoulder blades forwards, then backwards as far as you can take them.
- Squeeze your shoulder blades together at the back and hold for 3 seconds.
- Repeat this 10 times.
Shoulder adduction and abduction
- Lean on a table with your unaffected arm.
- Swing your affected arm outward and inward — let gravity do most of the work.
- Do this for 2 to 3 minutes.
Shoulder flexion and extension
- Lean on a table with your unaffected arm.
- Swing your affected arm backwards and forwards — let gravity do most of the work.
- Do this for 2 to 3 minutes.
Accident cover
The Accident Compensation Corporation (ACC) is a government agency that helps pay for treatment if you are injured in an accident.
The ACC provides comprehensive, no-fault personal injury cover for all residents and visitors to Aotearoa New Zealand. This means if you are hurt in an accident, ACC can help no matter who caused the accident.
If you have an accident and need emergency care in a hospital, it will be covered by ACC.
ACC usually pays some of the other medical costs if you have an accident, like surgery, physiotherapy and medicines. ACC may also be able to cover some loss of earnings resulting from an accident.