HealthInfo Canterbury
AC joint injuries
Ngā whara ki te hononga pokohiwi-manumanu
Your AC, or acromioclavicular (ak-ro-me-o-kla-vik-u-lar), joint is the joint at the very top of your shoulder. Injuries to this joint usually happen because you've fallen directly onto your shoulder.
An injured AC joint can range from mild to severe. 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 or move it 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 isn't too bad, you'll need to follow a programme of rest and exercise to help your joint heal. If your injury is more severe, you may need surgery.
Diagnosing an AC joint injury
Your doctor will diagnose a dislocated AC joint by listening to what happened and examining your shoulder. You'll also need an X-ray to show how bad your injury is. You may need several X-rays of your shoulder to check for other injuries. If your injury is more complex, you may need extra scans.
Self-care for an AC joint injury
There are some things you can do to help your recovery, whether or not you're having surgery.
- If you smoke, stop smoking. Continuing to smoke will slow down how quickly you heal.
- Don't do any heavy lifting, as this will only increase your pain and slow your recovery. You'll probably need some time off work to allow your shoulder to recover.
- Take regular pain relief. The best pain relief is paracetamol (Panadol). Take two tablets every four hours but no more than eight tablets a day.
- If you're 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. You may also find the information about soft tissue injury and RICE treatment useful.
- Keep your hand, wrist and elbow moving to stop them becoming stiff. As your pain gets better, start doing the shoulder blade squeeze and shoulder shrug exercises. You can also do shoulder adduction and abduction, flexion and extension.
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. Don't drive while your arm is in a sling.
If you have a simple injury, physiotherapy may help get you back to your normal activities and sport.
If your injury is more severe or if a simple injury doesn't get better with resting and physiotherapy, you may need surgery to help the injury heal.
If you need surgery, your doctor will refer you to an orthopaedic (bone) surgeon. Precisely 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 six weeks, which means you won't be able to drive for six weeks. You'll also have a course of physiotherapy to strengthen your shoulder and get it moving again.
You'll need to have some weeks off work. How long will depend on the type of injury and the type of work you do.
While you're recovering, it's best not to lift or carry anything on the injured side. For the six weeks your arm is in a sling you shouldn't lift anything at all – not even a cup of tea or coffee. After that you'll gradually be able to increase what you can lift and carry. But you shouldn't lift anything heavy until you have normal movement back in your arm. Your surgeon will let you know when it's safe to start lifting.
Getting help for an AC joint injury
If you have any concerns about how you're healing or have a lot of pain, see your general practice team.
If your arm feels stiff after the pain has gone and you're no longer wearing a sling, see a physiotherapist who can help you with exercises and help strengthen your arm.
ACC may be able to provide help while you aren't fit for work, such as home help or taxis to appointment as well as work compensation payments.
Written by HealthInfo clinical advisers. Last reviewed July 2022.
Sources
See also:
Review key: HISHI-13267
