A dislocated shoulder usually happens after a heavy fall onto the arm. It takes between 12 and 16 weeks to heal after the shoulder has been put back into place.

Dislocating your shoulder means the ball joint of your upper arm has popped out of the shoulder socket. The surrounding tissues may also have become overstretched or torn.

The shoulder is one of the easiest joints to dislocate because the ball joint sits in a very shallow socket. This makes the arm extremely mobile and able to move in many directions, but also means it's not very stable.

Most people dislocate their shoulder during a contact sport such as rugby, or in a sports-related accident. In older people the cause is often falling onto outstretched hands, for example after slipping on ice.

Shoulder dislocations can occur more easily in people who are highy flexible, such as those with joint hypermobility (loose joints). 

How do I know if I've dislocated my shoulder?

In most cases of dislocated shoulder, the ball part of the joint pops out in front of the shoulder socket. This is usually obvious because:

• you won't be able to move the arm and it will be extremely painful
• the shoulder will suddenly look square rather than round
• you may be able to see a lump or bulge (the top of the arm bone) under the skin in front of your shoulder

It's much more unusual for the bone to pop out of the back of the shoulder joint. This usually happens after an epileptic fit or electrocution injury and is less easy to spot.

What you should do

If you think you have dislocated your shoulder, go to your nearest accident and emergency (A&E) department immediately.

Don't try to pop your arm back in yourself, as this could damage the tissues, nerves and blood vessels around the shoulder joint.

While waiting for medical help, avoid moving your upper arm as much as possible. Place something soft, such as a folded blanket or pillow, in the gap between the arm and side of the chest to support it. If you can, make a simple sling to hold the lower arm across the chest, with the elbow bent at a right angle.

How a dislocated shoulder is treated

When you get to A&E, you will be assessed and examined. You will usually be X-rayed to make sure you haven't broken any bones, as it's fairly common for someone who has dislocated their shoulder to also break the bone of their upper arm or the joint.

If you do have a fracture, further scans may also be carried out to investigate it in more detail. Fractures with a shoulder dislocation will require specialist orthopaedic care and may involve surgery.

If you don’t have any fractures, your arm will be gently manipulated back into its shoulder joint using a procedure known as reduction.

Surgery is sometimes necessary if the tissues surrounding the joint are badly torn and the joint is not stable. If the tissues are overstretched but not torn, surgery can sometimes be avoided by doing appropriate exercises to strengthen the shoulder.

Reduction

You will be given some medication to sedate you and ensure you are as relaxed and pain-free as possible.

Reduction is usually carried out in the A&E department, but sometimes it is done in the operating theatre under general anaesthetic (where you are asleep) under the care of an orthopaedic team.

You will usually sit on the bed while the doctor rotates your arm around the shoulder joint until it goes back in its socket. This may take a few minutes.

Once the shoulder joint is back in place, you will often have another X-ray to check the shoulder is in the correct position.

Repairing tears in the shoulder tissues

Some people tear a rotator cuff tendon (bands of tissue that stretch over the top of the shoulder) as well as the labrum (the cuff of tough tissue surrounding and supporting the shoulder joint) when they dislocate their shoulder.

If these tissues have been damaged, you may need surgery to repair them. For some people, this can significantly reduce the risk of dislocating the same shoulder again in the future (see below).

These operations are carried out under general anaesthetic and are increasingly being done with keyhole surgery, using only small incisions and an arthroscope (a thin tube fitted with a light source and a camera).

Recovering from a dislocated shoulder

You can usually go home soon after reduction, but you'll need to rest your arm in a sling for a few weeks.

You will usually be referred to the orhopaedic department for follow-up care and you may also be referred to a physiotherapist for rehabilitation to strengthen your shoulder.

Arm and shoulder exercises

You may be asked to rest your arm in the sling for two to three weeks while the soft tissues around the shoulder repair themselves.

After this, a physiotherapist can show you some gentle arm and shoulder exercises to do at home with your arm out of its sling. These will help reduce stiffness, relieve some of the pain and build up strength in your shoulder muscles.

Before you begin your exercises, hold an ice pack (or a bag of frozen peas wrapped in a tea towel) on the shoulder for 10 to 15 minutes and take some painkillers.

For some useful exercises to get you started, see the NHS leaflet: rehabilitation after shoulder dislocation (PDF, 482kb).

It's normal to experience aching, discomfort or stretching when doing these exercises. However, if you have intense pain for more than 30 minutes, do the exercise less forcefully and less often.

It's better to do short, frequent sessions of five to 10 minutes four times a day rather than one long session, and to gradually increase the number of repetitions you do.

Pain relief

The shoulder may be very painful during the first two to three weeks at home and you may need to take painkillers, such as paracetamol or ibuprofen. Always follow the dosage instructions on the packet.

If this doesn't control the pain, see your GP for a prescription for a stronger painkiller, such as codeine.

Recovery time

You can stop wearing the sling after a few weeks, but it takes about 12 to 16 weeks to completely recover from a dislocated shoulder.

You can usually resume most activities within two weeks, but avoid heavy lifting and playing sports involving shoulder movements for six weeks to three months. Your orthopaedic surgeon and physiotherapist will advise you.

You'll probably be off work for two to four weeks, or longer if you have a physical job. Discuss this with your GP, physiotherapist or consultant.

If you've also broken your arm or shoulder joint, you may need to wear your sling for up to six weeks and recovery will take longer.

Dislocating the shoulder a second time

If you've dislocated your shoulder once, you're more likely to dislocate it again in the future – particularly if you're less than 20 years old.

Your chances of another dislocation depend partly on how well the tissues surrounding the joint healed the first time. It can help if the torn tissues were surgically repaired after the dislocated shoulder was fixed.

Regularly doing the exercises your physiotherapist recommends and avoiding awkward arm positions can also reduce the risk of dislocating your shoulder again.