What is a joint dislocation?
A dislocation is an injury in which the bones in a joint are forced apart and out of their usual positions. To dislocate the bones of a large joint usually needs considerable force (although there are exceptions to this).
Dislocations are usually caused by trauma which produces force on the joint, such as falls, accidents involving moving vehicles and collisions during contact sports. Less force is needed for smaller joints than for larger ones. It can become easier to dislocate joints that have dislocated before, as the surrounding tissues which hold the joint in place may have been stretched. Some people are more prone than others to dislocation.
Which are the most common joint dislocations?
Most joints in the body can be dislocated but some are dislocated more commonly than others. Dislocations of the shoulder (in adults) and the elbow (in children) are the most common. This article discusses the most common dislocations and how they are treated.
Joints allow bones to move against one another (articulate) to allow us to move our skeletons. Some joints, like the shoulder, are particularly mobile (having a wide range of movement of the bones). This is particularly so in flexible people like gymnasts and ballet dancers. Some joints, like the ankle or fingertip, have a smaller range of movement, mainly in one direction. Generally there is a trade-off between mobility and stability. Stable joints tend to dislocate less easily as there are more rigid structures holding them in place.
Mobile and stable joints
Joints which are more mobile tend to be at greater risk of dislocation. Comparing two ball and socket joints - the shoulder and the hip - makes the point. Both are similarly made, consisting of a ball of bone moving in a socket. Ball and socket joints can move in every direction. The price for this mobility is that there are many directions in which the joint could be 'pulled out'. However, the shoulder is more easily dislocated.
The shoulder has quite a shallow socket. This makes it even more mobile. It depends upon muscles, tendons and ligaments to keep it in place. These structures are easily damaged if enough force is applied. The muscles and ligaments around the shoulder tend to be stretchy and relatively vulnerable (compared to those around the hip). Thus the shoulder is relatively easy to dislocate.
The hip is much harder to dislocate even though it is also a ball and socket joint. This is because the socket is deeper and the ligaments and muscles much bigger and stronger. As a result we can't get the same range of movement from our hips as from our shoulders but in return the hip is more stable.
What increases the risk of joint dislocation?
Various factors can lead to joint dislocation, either because they weaken the support of the joint (meaning less force is needed to dislocate it) or because they make injury more likely. These include:
- Weakness of the supporting ligaments and muscles through age or lack of fitness.
- Older people may have poorer balance and be more vulnerable to falls.
- Young children can be at greater risk as they have laxer, more elastic supporting ligaments and are prone to falls and other injuries if left unsupervised.
- Previous dislocations which have stretched or torn the supporting tissues before. Repeated dislocations are particularly likely to follow first dislocation in the shoulder, kneecap and hip.
- Joint hypermobility. Hypermobility is particularly common in children but about 5% of adults have hypermobile joints. It can be caused by weak loose ligaments, weak muscles or shallow joint sockets.
- Inherited conditions which make the elastic tissues more 'stretchy' - for example, Ehlers-Danlos syndrome and Marfan's syndrome
- Increased risk through choice of physical activity, such as extreme sports and high-speed sports, contact sports with high impact, or sports involving speed with sudden turns on the feet.
- Operating heavy machinery.
- Smaller joints like fingers need less force to dislocate them than, say, the hip, purely because they are smaller.
What is a joint dislocation like?
Dislocation is usually sudden and extremely painful as the ends of the bones dislocate from one another. This is because tissues around the joint are stretched and torn. There will be bleeding and immediate swelling. The joint may look obviously deformed.
When two bones meet there are several structures holding them together. These include
- Strong tissues called ligaments around (and sometimes inside) the joint.
- A joint capsule - a fibrous surround to the joint.
- Tendons and muscles passing around and sometimes through the joint.
If the joint is disrupted and pulled apart these structures, plus the bones themselves, can be torn or fractured as a result. As a result of this and of the displacement of the ends of the bones, the joint cannot function as normal. Limbs and digits can't be moved, you may be unable to weight bear or, in the case of the jaw joint, open your mouth.
An additional complication is that nerves and blood vessels may be trapped or compressed by the abnormally positioned structures. This can result in further, increasing pain and in numbness and tingling. (It also means that dislocated joints need immediate medical attention in order to make sure than the blood and nerve supplies to tissues beyond the joint are still functioning normally.)
What should I do if I have a joint dislocation?
- You need to get medical help immediately.
- Depending on the dislocation, you may be in severe pain and be immobile.
- Do not try to put the joint back yourself - even if you can manage to do this without causing further damage you may trap nerves, blood vessels or other tissues between the bones as you do so.
- Cool the injured area and, if practical and possible, elevate it. Both of these will reduce swelling.
How are joint dislocations treated?
The aims of treatment are to assess the position of the joint and any associated injuries, then to restore it to its normal location without causing any further damage. Imaging such as X-rays may be needed to check for broken bones and you may need painkillers or an anaesthetic before the joint can be manipulated.
Dislocations ideally need to be put back (reduced) by trained healthcare professionals in a hospital setting rather than by able first aiders 'in the field'. This is because:
- Significant force may be required to pull the bones further apart in order to drop them back into their proper relationship. The joint may also need to be pulled out and rotated a little before being gently allowed back into place. This needs careful control. It is important that the person doing this knows exactly how to pull and turn the joint.
- The process is generally painful, particularly for large joints like the shoulder - and you will already be in pain.
- You may need X-rays before or after the process, as dislocations are commonly associated with breaks.
- Essential structures like blood vessels and nerves may be put at risk by dislocation. They may be put further at risk if a dislocation is then put back improperly, or manipulated the wrong way, trapping them and possibly cutting off blood or nerve supplies. This could make things worse.
Afterwards treatment focuses on rehabilitation and prevention of further dislocation. You are likely to be offered physiotherapy for the joint involved.
How long does it take to recover from a joint dislocation?
There will be some immediate relief when the joint is back in place. However, the tissues will still be sore, swollen and bruised. The time that this takes to fully recover depends on the size of the joint involved and the amount of associated damage to the supporting structures. It also depends on the treatment that's needed and on the physiotherapy that you do.
Time to reach complete recovery may vary. It may be only 2-3 weeks in the case of a partial finger dislocation that goes back into place easily. For a shoulder, it may be 12-16 weeks. However, in the case of a hip or a foot, it may take six months or longer. When there are repeated dislocations of the kneecap, the bone may eventually slip so easily back into place that recovery is almost immediate. This is because the muscle has become so stretched that no further damage occurs when the kneecap dislocates.
Healing and recovery time will be affected by factors such as:
- Severity of injury.
- Whether surgical repair is needed.
- Strength of supporting muscles and ligaments.
- General health.
- Presence of conditions which may affect healing - for example, poorly controlled diabetes, oral steroid use.
- Compliance with treatment (for example, doing your physiotherapy exercises).
- Whether injury is repeated (recurrent).
Common joint dislocations: shoulder, elbow, knee, hip, finger, collarbone, jaw, wrist and foot
This occurs when the ball of the upper arm bone (humerus) pops out of the shoulder socket. It is usually caused by a fall on to the upper arm, or during contact sport such as rugby. Usually the dislocated ball pops out at the front of the shoulder joint, where the supporting muscles are at their weakest. It can pop out backwards but this is relatively uncommon.
Forwards (or anterior) dislocations of the shoulder are extremely painful and you won't be able to move the arm. There may be a deforming bulge in the front of your shoulder area, below the natural shoulder joint. This will be the head of the bone that has slipped out.
Shoulder dislocations are at high risk of involving nerves and blood vessels. It is also fairly common to find an associated fracture of the upper arm or shoulder, and you should not try to put the shoulder back by yourself as you may trap these important structures.
Treatment of a shoulder dislocation
- Shoulder dislocation is usually treated in hospital. X-rays are done to check for breaks, which are common. The shoulder is then put back (reduced) using either strong painkillers or an anaesthetic. The process takes only a few minutes. If any of the tendons or tough tissues around the shoulder (including the labrum, which is the 'lip' of the shoulder socket) have been torn they may need surgical repair.
- After reduction you will normally need to rest the shoulder for several weeks: it is likely to be 12-16 weeks before full strength is regained. This may be longer if bones were also broken.
- You will usually wear a sling for 2-3 weeks to allow the stretched soft tissues to heal.
- After this, gentle arm and shoulder exercises, performed out of the sling, help to regain mobility and strength. A fifteen-minute ice pack and painkillers may be useful before the exercises are attempted.
If you have dislocated your shoulder once, you are more likely to do it again. This is particularly the case if you are under 20 years old the first time. If shoulder dislocation recurs the structures at the front of the joint can become stretched. Eventually a point may be reached, with repeated dislocations, where the shoulder dislocates very easily, even during normal sporting activities like swimming. Sometimes it can even be slipped back in relatively easily by you alone. In such cases physiotherapy or surgery may be offered to increase the support around the shoulder and to reduce the chance of further dislocations.
The elbow is the second most common dislocation in adults and the most common in children. It takes a lot of force to dislocate the elbow - such force that there is often an associated crack or break in one of the bones. Dislocated elbows are at high risk of trapping nerves and blood vessels and need urgent attention.
The most common cause is a fall on to an outstretched hand or arm, pushing the forearm bone sideways out of the joint. Sports like cycling, roller blading, skateboarding and gymnastics tend to be the most common sports-related causes.
Dislocated elbows look deformed and they hurt. There may be swelling and bruising, especially if there are torn ligaments or broken bones. Injury to the nerves that cross the elbow joint can cause tingling further down the arm or in the hand.
Treatment of an elbow dislocation
This follows the same principles as for shoulder dislocation, above, although the elbow does sometimes relocate by itself, particularly if it wasn't completely dislocated. Reduction is done by a trained medical person. A sling is worn initially, after which you should be offered physiotherapy to restore normal movements and control.
If essential structures like ligaments have been damaged then surgery may be needed to repair them. If the bones are broken then pinning and wiring may be needed to hold everything stable as it heals. In more complicated cases the elbow may be in a cast or brace for a while before physiotherapy can begin.
Partial dislocations of the elbow ('nursemaid's elbow') are very common in children aged 1-4 years. A partial dislocation occurs when the head (elbow end) of one of the forearm bones (the radius) comes out of the looped ligament which holds it in place (the annular ligament). This happens easily in children, as they have a rather lax, stretchy annular ligament. A tug on the child's arm could be the cause. This might occur when holding a child by the hand whilst walking. If the child trips without the adult noticing, they can suddenly dangle by the arm. The condition causes pain and the child can't move their elbow properly. However, the elbow is quite easy for a trained health professional to 'put back' in casualty.
Knee dislocation (dislocated kneecap)
The common knee dislocation is actually of the kneecap (patella) from the joint, rather than of the thigh bone (femur) and the shin bone (tibia) from each other. Patellar dislocation is particularly common in teenagers, especially girls. It can happen during sport but also when getting up from a chair or the floor.
The kneecap is said to dislocate when it comes sideways out of the groove in which it normally moves over the knee joint. The kneecap is really a sesamoid bone. This is a bone sitting in a muscle over the top of a joint, protecting it by sliding over it to cover the most prominent part of the knee as the joint moves.
The kneecap sits in the muscle forming the front of the thigh (the quadriceps muscle). Below the kneecap the quadriceps muscle turns into a tendon and attaches to the front of the shin bone. When dislocated it pops out of the groove - usually outwards from the other leg (laterally), still remaining attached to the muscle, which stretches and moves with it.
A dislocated kneecap hurts and you may hear a crack or clunk. There may be swelling, particularly the first time it happens. You will be unable to move the knee properly or walk. This dislocation does not generally represent a risk to major nerves and blood vessels.
Kneecap dislocation tends to be repeated (recur). The risk is higher if the quadriceps muscles are not particularly strong, so that they tend to be lax and allow sideways movement of the kneecap. The risk is greater if you are overweight. Over time the dislocation may become less painful, as the stretched tissues are not damaged by the dislocation.
Treatment of a dislocated kneecap
Dislocated kneecaps often treat themselves, popping back into place before you even get to see a health professional. Over time if you have the condition recurrently it will become less painful and you may be able to put it back yourself. This is usually achieved by slowly straightening the leg - or allowing someone else to straighten it for you.
If this doesn't work, the kneecap dislocation can be put back by a qualified health professional. You will be offered physiotherapy afterwards to strengthen the quadriceps muscles.
Traumatic hip dislocation is a medical emergency when it occurs in adults. It is very painful and can result in significant blood loss into the joint and tissues. The hip is a stable joint, seated in a fairly deep socket and well protected by large muscles and strong ligaments. It takes a lot of force to pop it out and such severe force is likely to cause other associated injuries.
What you have done may not be obvious by looking at the hip, since the bones are well covered with muscle layers so swelling and bruising may not be obvious. However, you will be unable to stand or move your hip joint and, when lying down, the leg on the affected side will look shorter than the other. Most hips dislocate out backwards and when this happens the whole leg tends to rotate inwards towards the other leg.
Hip dislocations are of three main sorts:
- After major trauma such as a road accident.
- Dislocation of artificial hips in the period following surgery - this is relatively common as the muscles and ligaments around the false joint ball will be stretched and weakened by the surgery.
- Congenital hip dislocation, or developmental dysplasia of the hip. This is seen in babies with shallow hip sockets whose hips slip out. It is more common in premature babies and in boys. This is covered in a separate leaflet.
In addition some adults do have a shallow hip socket and develop recurrent dislocation, usually in later life when the supporting joints and ligaments are weaker.
Treatment of a hip dislocation
Patients with traumatic hip dislocation need pain relief and treatment for other injuries, which may include shock and blood loss. The hip dislocation itself will normally be put back under anaesthetic. The risk of damage to blood vessels and nerves is quite significant. There is a chance of permanent interruption of the blood supply to the ball part of the ball and socket joint. This leads rapidly to arthritis of the hip. Traumatic hip dislocations therefore commonly lead to lasting disabilities.
Dislocations following hip surgery and dislocations that are recurrent also require reduction under anaesthesia. They tend not to be as traumatic, as they have not required the same level of force to cause them.
This is a common injury which can affect any finger joint but which most commonly affects the middle knuckle of the four fingers (rather than the thumb). It is usually caused either by overextending the finger backwards, or by jamming or catching the finger somewhere during fast movement. Typically this happens:
- During sports activities when stopping fast balls with the hand.
- When undressing and catching the finger in clothes.
- When falling on to the hand.
It is usually obvious - the finger will be deformed (crooked and swollen) and will hurt. You won't be able to move it properly and it may go pale and tingle.
Treatment of a dislocated finger
You should see a healthcare professional if you have a dislocated finger. This is particularly urgent in the following cases:
- The finger is pale or tingling (which suggests trapped nerves or arteries).
- The skin is broken over the dislocation (risking infection in the damaged joint).
You should also remove any rings swiftly, if possible. This is because they may need to be cut off if a finger swells and the rings become too tight.
A dislocated finger is usually put back in accident and emergency. It will probably be X-rayed. Ice is usually applied. Depending on the severity, you may be sent to see a hand specialist afterwards to make sure you get back the full function of the hand.
Dislocated collarbone (clavicle)
This most commonly means dislocation of the outer end joint of the clavicle, where it articulates with the top of the shoulder. This is called the acromioclavicular joint (ACJ) and the dislocation is also called AC separation. The ACJ is most commonly dislocated by a fall on to an outstretched arm or on to the tip of the shoulder. It often occurs in physical 'collision' sports like rugby and football. It can also occur in sports that can involve falling, such as skiing and horse-riding.
The dislocation is painful. It may be easier to spot the distortion of the joint shape when the arm is held across the body. The severity can vary from a small separation of the joint to a wide one.
Treatment of a dislocated collarbone
Treatment of this dislocation depends on how severe it is. This is judged by how widely the bones have separated and how much damage there is to the supporting ligaments. More severe injuries will need surgical reduction and fixation. However, less severe injuries are managed with physiotherapy and painkillers.
Dislocated jaw (temporomandibular) joint
The temporomandibular joints (TMJs) are the joints between your lower jaw. They can dislocate quite easily in some people, even through opening the mouth particularly wide, yawning, kissing, or biting an apple. Pain is felt in front of the ear and it is difficult to open and close the mouth. Usually the jaw dislocates forwards. However, in the case of a direct blow to the chin it may dislocate backwards.
Treatment of a dislocated jaw
The joint needs to be put back by a trained health professional. The main chewing muscles (masseter muscles) are very strong. Once the jaw has dislocated they may be in spasm, so muscle relaxants are sometimes used. If the reduction proves difficult or there are other injuries, an anaesthetic may be needed.
You will need to follow a soft diet as you recover from a dislocated or broken jaw, avoiding foods that are crunchy or particularly chewy.
Wrist dislocation means dislocation of any of the eight small bones which make up the wrist. It is usually caused by a fall on to the wrist or the outstretched arm. Symptoms include pain and obvious distortion of the wrist.
There are a number of ways in which the eight wrist bones can dislocate and the lunate bone is usually involved.
Treatment of a dislocated wrist
Dislocation of wrist bones generally involves severe ligament damage and needs treating by a specialist hand surgeon to avoid permanent damage to the wrist. Once the wrist has been put back and the ligaments repaired, a plaster cast is generally necessary to keep everything still whilst it heals.
Important nerves and arteries run through the wrist and if numbness and tingling develops in the fingers when the wrist is dislocated then this is a medical emergency, as it suggests these structures are trapped or damaged.
There are many possible kinds of dislocation that can occur in the foot, which contains multiple bones and joints. The common dislocation is called a Lisfranc injury. This is because the group of joints that join the arch area of the foot (the midfoot) to the long metatarsal bones (the forefoot) is called the Lisfranc complex. If bones in the midfoot are broken or ligaments that support the midfoot are torn then dislocations in the Lisfranc area can result.
Lisfranc injury can result from a simple twist and fall. However, more often it occurs following road traffic accidents and other major trauma. It is also seen in some sports and performance arts like American football and ballet, where there is a twisting injury to the feet.
The foot will usually be painful and swollen and the swelling may at first hide the fact that there is deformity of the shape. A Lisfranc injury is often mistaken for a sprain, especially if the injury is a result of a straightforward twist and fall. However, injury to the Lisfranc joint is a severe injury that may take many months to heal and may require surgery to treat.
Treatment of a dislocated foot
Foot dislocation, which usually involves broken bones in the midfoot, needs treatment by a foot specialist. Small dislocations where the bones are not forced too far apart may heal by themselves although the foot needs to be in a cast and completely non weight-bearing. More severe injuries need surgical treatment to restore the normal function of the foot.
How can I prevent joint dislocations?
The prevention of joint dislocations involves:
- Improved strengthening to muscles around joints - for example, through:
- Fitness training and/or physiotherapy.
- A healthy diet.
- Aiming to be the appropriate weight for your height.
- Improved balance, through fitness and through exercises which strengthen the body's core muscles.
- Minimisation of risk taken during sporting activities - for example, with appropriate equipment and with specific training on technique.
- Seeking medical advice if dislocation becomes repeated (recurrent). There may be a preventative operation which would stop the dislocations.
- In the case of jaw dislocations brought on by yawning, reducing the risk by supporting your chin when you yawn.
- In the case of recurrent dislocation, avoiding the activities and positions which tend to cause it.
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