Dislocated shoulder

The shoulder joint pays for its range of movement with stability. The head of the upper arm bone is round and large, while the socket on the shoulder blade is shallow and only about a third of its size: the bone does not sit in a cup but rests against a saucer, held there by ligaments, a rim of cartilage and muscle. Let the lever get too long and the head comes out. This is the commonest dislocation in the human body, and it has to be put back in hospital: the longer the shoulder stays out, the harder it is to return and the more of the surrounding tissue is damaged in the meantime.

How it happens and where the bone goes

In the overwhelming majority of cases the head slips forwards and downwards. The classic story is a fall onto an outstretched arm held away from the body, a grab at a handrail, a wrestling hold, a ball thrown from above the head. The danger is not the force itself but the combination: the arm out to the side and turned outwards.

Far less often the head goes backwards, and that version deserves a paragraph of its own because it is the one most often missed. Posterior dislocation happens during a seizure and after an electric shock, lightning included: the muscles all contract at once and the stronger ones twist the shoulder inwards. From outside the arm looks almost normal, the shape of the shoulder barely changes, the pain is put down to a bruise and the person is sent home. There is one thing that gives it away: the arm is locked against the abdomen and turned inwards, and the palm cannot be turned upwards, not by the patient and not with help. If the shoulder hurts after a seizure or a shock and will not rotate outwards, X-rays in two views are needed, and the circumstances of the injury have to be spelled out to the doctor.

Very rarely the arm becomes stuck raised above the head and will not come down. That too is a dislocation, and it can only be dealt with in hospital.

How to tell the shoulder is out

Usually the person knows before anyone examines them: the pain is sudden, the arm feels like someone else's and it cannot be lowered or held against the body. Several signs go with that.

• The arm hangs slightly away from the body and turned a little outwards, and the injured person supports it with the good hand, afraid to move.
• The shoulder loses its roundness: instead of a smooth curve there is a corner, the bony point of the shoulder blade stands out clearly under the skin and just below it there is a hollow.
• Any attempt to move the upper arm produces severe pain, while the fingers and wrist still move normally.
• Within an hour or two the swelling builds, and later bruising comes out, sometimes as far as the elbow.

A fracture of the upper end of the arm bone and a torn collarbone ligament feel much the same, so the definitive answer comes from an X-ray. It also shows whether a fragment of bone has come away with the dislocation, which affects how the shoulder will be put back.

What to do before hospital

You need the emergency department, and preferably not behind the wheel: the pain and the painkiller both get in the way of driving. Ask someone to take you or call an ambulance; across Europe the single number is 112. While you wait:

• hold the arm still in whatever position hurts least: sling it in a scarf, a shawl or a towel and tuck something soft and rolled up between the arm and the chest;
• apply something cold wrapped in cloth for about twenty minutes, repeating every two or three hours; ice does not go straight onto the skin;
• take your watch, bracelets and rings off that hand before the swelling comes up;
• take an ordinary over-the-counter painkiller at the dose on the packet, if there is no reason for you to avoid it;
• eat and drink nothing on the way. Reduction is often done under strong pain relief or a short anaesthetic, and a full stomach means putting it off for several hours;
• bring a list of your medicines, blood thinners above all.

And one flat prohibition: do not try to put the shoulder back yourself and do not let someone who "knows how" try it either. Without an X-ray nobody knows whether there is a fracture, and a blind wrench breaks bone, tears ligaments and injures the nerve. Do not move the upper arm and do not keep testing whether it has gone back in on its own.

When there is no time to lose

Any dislocation means leaving straight away, but there are signs that call for an ambulance rather than your own transport:

• the hand has turned pale or blue and cold and there is no pulse at the wrist: a blood vessel is involved;
• a patch of skin over the outer shoulder has gone numb, roughly where a badge is sewn onto a uniform, or the arm feels nothing at all: a nerve is damaged;
• the fingers will not move or the hand has lost its grip;
• the shoulder is deformed after a heavy blow, a fall from height or a road accident, where broken ribs, a broken collarbone or a lung injury may sit alongside it;
• there is a wound over the joint with bone visible in it;
• the dislocation happened during a seizure, a blackout or an electric shock.

Sensation and pulse are checked by the doctor before the shoulder goes back and again immediately afterwards. That is a compulsory part of the examination, so do not be surprised at being asked twice to wiggle your fingers and say where you can feel a touch.

How the shoulder is put back

X-ray first, pain relief second. A shoulder is not reduced cold: pain makes the muscles clench, and the head will not travel through a clenched muscle. Strong painkillers through a vein, an injection of local anaesthetic into the joint or a short anaesthetic are all used, and the choice depends on the injury, the age, other illnesses and local practice.

The manoeuvre itself is not a jerk but a slow pull lasting several minutes with a gentle rotation of the arm until the head slides home. The moment it goes back is usually felt by doctor and patient alike, as the pain suddenly lets go. A check X-ray follows, sensation and pulse are tested again, and the arm goes into a sling.

If a bone is broken along with the dislocation, if the head cannot be put back or if it comes out again, an operation will be needed. The same operation is offered later, as a planned procedure, to people whose shoulder dislocates repeatedly.

The first weeks afterwards

The sling is usually worn for one to three weeks. Longer is not better, because the joint stiffens quickly and loses movement. The exact period is set by the doctor, since it depends on what has been damaged.

Then the real work begins: getting movement and strength back. Physiotherapy here is not a pleasant extra but the thing that decides whether the shoulder comes out again, because it is muscle that holds the joint in place and weak muscle will not hold it. Returning to ordinary life generally takes about three months, and returning to sport that loads the arms up to four months or more.

For the first weeks avoid one particular position, the arm out to the side and turned outwards: winding up to throw, the throw itself, reaching for something on a high shelf behind you, sleeping with the arm under your head. That is the position in which a shoulder comes out a second time. When you can drive again, lift weight and go back to the gym is decided by the doctor on how the arm moves, not by the calendar.

Go back for review if weeks after the reduction the arm still cannot be lifted actively although someone else can lift it for you, if numbness persists, or if pain keeps you awake at night. In people over forty a first dislocation frequently tears the rotator cuff, the group of tendons that raises the arm, and that tear is often picked up late because the weakness gets blamed on the injury itself.

Why a shoulder dislocates again

Once a shoulder has come out it stays vulnerable: the ligaments and the cartilage rim stretch or pull away, and the catch no longer holds as it did. The main factor is the age at the first dislocation. The younger the person, the higher the chance of it happening again: in teenagers and young athletes it is very high indeed, and past forty it drops considerably, though there tendon tears come to the fore instead.

What genuinely lowers the risk:

• finishing the rehabilitation rather than dropping it as soon as the pain stops, which is the commonest mistake of all;
• strengthening the muscles of the shoulder blade and the rotator cuff, not only the ones visible in the mirror;
• discussing further imaging of the joint with the doctor if the shoulder has come out even twice, since it shows exactly what has been torn away;
• considering surgery if the shoulder keeps coming out or if you play a contact sport. The operation repairs the detached rim and ligaments, and afterwards the risk of recurrence falls several times over.

There are also people whose shoulder slips out with almost no injury at all, on an awkward movement, and that usually means ligaments that have been unusually stretchy since birth. Surgery works less well for them, whereas targeted supervised exercise works very well indeed, and that is exactly where to start.

Online consultation

A fresh dislocation is not something a screen can treat: if the shoulder has changed shape and the arm will not move, you need the emergency department and the conversation ends there. Everything that comes afterwards, though, is well suited to a remote appointment. The doctor goes through the discharge letter and the images, explains what has been damaged and why the sling has been set for that long, helps put the recovery in order and points out which movements are still off limits. It is also the way to work out whether a weak arm a month on is normal or whether it is time to look for a torn tendon, and to weigh up whether surgery makes sense when the shoulder has come out more than once.

This material is for information only and does not replace medical advice.