A dislocated shoulder usually happens after a heavy fall onto the arm. It takes between 12 and 16 weeks to heal after the arm has been reconnected.
Dislocating your shoulder means your arm bone has popped out of its shoulder socket and the supporting tissues may have overstretched or torn.
The shoulder is one of the easiest joints to dislocate. This is because the top of the arm bone, which is shaped like a ball, sits in a very shallow socket. While this makes the arm extremely mobile and able to move in many directions, it also means that 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 usually falling onto outstretched hands, for example after slipping on ice.
Shoulder dislocations can occur more easily in people who are very flexible, such as those with joint hypermobility (loose joints).
How do I know if I've dislocated my shoulder?
In nearly all cases of dislocated shoulder, the arm bone pops out in front of the shoulder socket. This is usually obvious because:
- 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
- you won't be able to move the arm and it will be extremely painful
It is 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. Some people who are extremely flexible can dislocate their shoulders in more than one direction.
What you should do
If you think you have dislocated your shoulder, go to your nearest accident and emergency (A&E) department immediately. This is important, as you will need some tests to find out whether you have any nerve damage.
A doctor will gently manipulate your arm bone back into its socket using a procedure known as reduction.
If your shoulder has dislocated without any major accident and you've managed to gently manipulate the arm back into place, there may be no need to go to A&E. However, it's a good idea to see a GP or physiotherapist, who can check on the shoulder and provide advice on exercises.
How a dislocated shoulder is treated
Most dislocated shoulders should be treated in a hospital A&E department.
Your shoulder will first be X-rayed to make sure you haven't broken any bones. It's fairly common for someone who has dislocated their shoulder to also break the top of their humerus, the arm bone running from the shoulder to the elbow. A fractured humerus is most likely to happen in older people, whose bones have weakened with age.
Read about how a broken arm is treated.
An ultrasound scan will be needed to reveal if the rotator cuff tendons have torn – these are the bands of tissue that stretch over the top of the shoulder. It is common to tear a rotator cuff tendon as well as the labrum, the cuff of tough tissue surrounding and supporting the shoulder joint. Rotator cuff tears are more likely to happen in older people, whose tissues are weaker.
Your arm will be supported in a sling, with your elbow bent at a right angle, and a pillow may be placed in the space between your arm and chest to provide comfort and support. Both the pillow and sling will be secured to your chest.
Your arm will then 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 not torn but overstretched, surgery can be avoided by doing appropriate exercises to strengthen the shoulder.
You will be given some medication to sedate you, which ensures you are relaxed and as pain-free as possible.
Reduction will usually be carried out in the A&E department, but sometimes it is done in the operating theatre under general anaesthetic.
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 may have further tests to check the bone is in the correct position and there's no other injury.
Repairing tears in the shoulder tissues
You may need surgery if you've torn the rotator cuff tendon. This involves stitching the tendon back onto the upper arm bone.
If you've torn the labrum, you'll probably need surgery to reattach this to the socket of the shoulder. A 2008 study showed that the risk of dislocating the shoulder a second time was greatly reduced in adults under the age of 35 if their torn labrum was repaired first time round.
This operation is increasingly being done using keyhole surgery, using only a small incision and an arthroscope (a thin tube fitted with a light source and a camera).
Repairing the rotator cuff tendon and reattaching the labrum are carried out under a general anaesthetic.
Recovering from a dislocated shoulder
After reduction, you'll need to rest your arm in a sling for a few weeks. You'll usually be referred to a physiotherapist for rehabilitation to strengthen your shoulder.
Arm and shoulder exercises
Your physiotherapist will 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.
It is also important to have good posture while in and out of the sling so you don't create further weakness around the shoulder.
Before you begin your exercises, hold an ice pack to the shoulder (try a bag of frozen peas wrapped in a tea towel) for 10-15 minutes and take some painkillers.
For some useful exercises to get you started, see pages 7-8 of the NHS leaflet Rehabilitation after shoulder dislocation (PDF, 482kb).
Gradually increase the range of movement in your shoulder and gently move the arm into positions that challenge the shoulder muscles.
It is normal to feel 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 5-10 minutes four times a day rather than one long session, and to gradually increase the number of repetitions you do.
The shoulder may be very painful during the first two to three weeks at home and you may need to take painkillers. Try 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.
If you've torn the tissue surrounding the shoulder joint, you may need a steroid injection into the shoulder to reduce the pain and inflammation.
You'll need to wear the sling for a few weeks, but it takes about 12-16 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 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, you'll need to wear the sling for up to six weeks and recovery will take longer.