A dislocated shoulder occurs when the ball (known as the head) of the shoulder joint (humerus) is forcibly separated from the socket of the shoulder blade (scapula). The ball, which is relatively large, fits into a shallow socket, making the shoulder joint very mobile but very unstable. This makes it susceptible to partial dislocation (subluxation) and dislocation. A dislocation is a severe joint injury involving tearing of ligaments and other structures around the shoulder. Once the joint is relocated, it is not ‘fixed’. The shoulder needs ongoing treatment and rehabilitation to repair the soft tissue damage and to restore strength and safe flexibility.
Tell me more about shoulder dislocation.
Physiotherapists have many skills that can help with your rehabilitation. 95 per cent of shoulder dislocations are anterior, where the humeral head moves in front of the body. Anterior dislocations usually occur in younger individuals. Posterior dislocations, where the head of the humerus is displaced backwards, are much less common but as a consequence can often go undiagnosed initially.
As many as 90 per cent of athletes aged under 40 will repeatedly dislocate their shoulder. This is because of the position of the shoulder (abducted and externally rotated) during overhead activities such as swimming and throwing. Sometimes the axillary nerve may be damaged during the dislocation, which can cause temporary weakness to the deltoid muscle making it difficult to lift the arm.
What causes shoulder dislocation?
Anterior shoulder dislocations are often caused by a direct blow to the shoulder or by a fall on an outstretched hand.
Some people have very loose joints and are very mobile so can easily put their palms to the floor and place their thumbs back onto their wrist. These individuals often have recurrent dislocations and subluxations (partial dislocations) of their shoulders in what’s called a ‘postero-inferior direction’. This condition is referred to as multidirectional instability (MDI).
You can also see downward (inferior) subluxation of the shoulder in people who have had a stroke, because the muscles around the shoulder are weakened. The shoulder muscles cannot stop the downward pull of gravity, so the humeral head gradually falls down out of the socket. Shoulder subluxation can be a great source of pain for a stroke patient.
How do I know if I have dislocated shoulder?
You will have acute, searing pain radiating down your arm and you will be unable to move your arm from its current position. Your shoulder will look out of position and someone examining you will not be able to feel the bone at the back of your shoulder. Your arm may feel numb, indicating nerve damage. You will need an X-ray to determine the position of your humeral head relative to the socket and to determine if there is also a fracture. A first-time shoulder dislocation will often need to be treated in the emergency department of the hospital.
How can physiotherapy help with shoulder dislocation?
Initially an acute shoulder dislocation needs to be relocated and then immobilised for 3–6 weeks to allow the soft tissues to repair. The shoulder can be immobilised in a sling, but the best method is to use tape so the soft tissues are shortened. Exercises that involve isometric (without joint movement) muscle contractions of the shoulder blade muscles (scapular muscles) can be started at this point.
Once your shoulder is pain-free more functional training can be started with your rotator cuff muscles.
Deltoid strengthening is also a focus of physiotherapy, particularly if you injured your axillary nerve. Your physiotherapist must ensure you have good control of your core and legs so you are not putting extra pressure on your shoulder. You will need to build up the endurance, as well as the strength of your shoulder muscles.
You will be given exercises to improve the ‘proprioception’ of your joint, because your injury means the subtle adjustments your shoulder automatically makes in response to different loads will no longer occur as normal and will have to be retrained.
How effective is physiotherapy for shoulder dislocation?
Unfortunately, re-dislocation is extremely common in young, athletic individuals. This is due to incomplete or prolonged healing of the ligaments that keep the humeral head in place.
This means physiotherapy alone may not be effective in stabilising the joint. If you work hard at your physiotherapy rehabilitation program following a dislocation, you will give yourself the best chance of regaining strength and muscle control, perhaps to the point where you can avoid surgery. If surgery is required later your efforts are not wasted, because you will go into the operation with a fitter shoulder that has a better chance of recovery.
If you have had more than one dislocation you may need stabilisation surgery, after which you will need to follow an intensive post-operative physiotherapy program to achieve the best results.
What can I do at home?
With an acute dislocation you must rest until the structures are healed. You won’t be able to drive your car and you must avoid activities where your arm is out from your side and your shoulder is externally rotated (hand back behind elbow), for example putting on your seat belt or doing your hair.
Once your shoulder is pain-free with all movements, you can do exercises at home to strengthen your rotator cuff muscles. Place your arm out to the side just out from your body to begin with (you don’t want to reinjure yourself), and let your forearm go gently back past the elbow (comfortable external rotation), while you maintain a lift of your sternum. You will then gently bring your forearm slightly forward so the hand is just in front of the elbow (small amount of internal rotation), using a light resistance band. The band can be used for resistance to control concentric (shortening) and eccentric (lengthening) exercises of your rotator cuff.
You can also do exercises to strengthen your legs and your core, provided you don’t stress your shoulder. This means sit-ups should be avoided.
How long until I feel better?
A dislocated shoulder takes up to three months to feel more secure, but if you want to return to sport it will be 6–12 months before you will be able to participate safely in your chosen sport. Your return to sport must be guided by achieving rehabilitation milestones, how confident you feel using your shoulder and a performance test before a full return to training.
Running should be avoided for at least six weeks, as the action of the arms will delay healing and increase pain. One option for maintaining your fitness is to ride an exercise bike.