Overview of Dislocations

The injury that causes the dislocation may also have caused a fracture. Rarely, fractures cause nearby injured muscles to swell so much that they reduce or block blood flow to the injured limb. If blood flow is not restored, the limb eventually feels cool and turns blue, and tissues in the limb become damaged or die. This disorder is called compartment syndrome Compartment Syndrome Compartment syndrome is increased pressure in the space around certain muscles. It occurs when injured muscles swell so much that they cut off their blood supply. Pain in the injured limb increases... read more .

A dislocated hip or knee can disrupt blood flow to the leg. Thus, the tissues in the leg may not get enough blood (called ischemia) and may die (called necrosis). A dislocated hip Hip Dislocations Hip dislocations occur when the ball-shaped head of the thighbone (femur) pops out of the rounded socket of the hip bone (pelvis). Usually, hips are dislocated when a great force hits a bent... read more is prone to necrosis, particularly if it is not realigned quickly. When the hip is dislocated,the blood vessels to the upper end of the thighbone (the part of the hip joint called the femoral head) are stretched. As a result, this part of the thighbone does not get enough blood. When the knee is dislocated, the lower leg may not get enough blood. If the lack of blood causes a large amount of tissue to die, part of the leg may have to be amputated. Certain elbow injuries can disrupt blood flow to the forearm, causing similar problems. A disrupted blood supply may not cause any symptoms until several hours after the injury.

Severe or traumatic dislocations can injure tissues around them and cause internal bleeding. A dislocated bone may break the skin and cause external bleeding.

Sometimes nerves are stretched, bruised, or crushed when a joint is dislocated. A direct blow can bruise or crush a nerve. Crushing causes more damage than bruising. These injuries usually heal on their own over weeks to months to years, depending on the severity of the injury.

Rarely, nerves are torn. Torn nerves do not heal on their own and may have to be repaired surgically.

Some nerve injuries never heal completely.

If the skin is torn when a joint is dislocated, the wound may become infected, and the infection may spread to the bone (called osteomyelitis Osteomyelitis Osteomyelitis is a bone infection usually caused by bacteria, mycobacteria, or fungi. Bacteria, mycobacteria, or fungi can infect bones by spreading through the bloodstream or, more often, by... read more ). Osteomyelitis is very difficult to cure.

Sometimes a dislocation damages the cartilage at the ends of bones in the joint (called joint surfaces). Normally, this smooth, tough, protective tissue enables joints to move smoothly. Damaged cartilage tends to scar, causing osteoarthritis Osteoarthritis (OA) Osteoarthritis is a chronic disorder that causes damage to the cartilage and surrounding tissues and is characterized by pain, stiffness, and loss of function. Arthritis due to damage of joint... read more , which makes joints stiff and limits their range of motion. The knee, elbow, and shoulder are particularly likely to become stiff after they are dislocated, especially in older people. Also, the injury that causes the dislocation may weaken or tear the tissues that stabilize the joint, such as ligaments and tendons.

Physical therapy is usually needed to prevent stiffness and help the joint move as normally as possible. Surgery is often needed to repair the damaged cartilage. After such surgery, the cartilage is less likely to scar, and if scarring occurs, it tends to be less severe. Surgery is sometimes needed to repair torn ligaments or tendons.

Doctors ask the person (or a witness) to describe what happened. Often, the person does not remember how an injury occurred or cannot describe it accurately. Knowing how the injury occurred can help doctors determine the type of injury. Also, doctors ask in which direction the joint was stressed during the injury.

Doctors also ask when the pain started. If it started immediately after the injury, the cause may be a dislocation, fracture, or a severe sprain. If the pain began hours to days later, the injury is usually minor. If the pain is more severe than expected for the injury or if the pain steadily worsens during the first hours after the injury, compartment syndrome may have developed or blood flow may be disrupted.

The physical examination includes the following (in order of priority):

To check for signs of blood vessel damage and disrupted blood flow, doctors check pulses and skin color and temperature. When blood flow is disrupted (as can occur in compartment syndrome), pulses eventually disappear or become weak and the skin becomes pale and cool. Doctors measure blood pressure, which is low in people who have lost a lot of blood.

To check for nerve damage, doctors test whether the person can move muscles normally. If the person cannot move the affected muscles, the nerves that control those muscles (called motor nerves) may have been damaged. Doctors also evaluate sensation in the skin—whether the person can feel normally—and ask whether the person has abnormal sensations, such as a pins-and-needles sensation, tingling, or numbness. If sensations are abnormal or decreased, the nerves that are responsible for skin sensation (called sensory nerves) may have been damaged.

Doctors gently feel the injured part to determine whether bones are out of place and whether the area is tender. Doctors also check for swelling and bruising. They ask whether the person can use, put weight on, and move the injured part.

Doctors test the stability of a joint by gently moving it, but if a fracture or dislocation is possible, x-rays are done first to determine whether moving the joint is safe. Doctors check for grating or crackling sounds (crepitus) when the injured part is moved. These sounds may indicate a fracture. Moving the affected joint can also help doctors determine the severity of an injury.

Doctors also check the joint above and below the injured joint.

Stress testing may be done to evaluate the stability of an injured joint. However, if a fracture or dislocation is suspected, stress testing is postponed until x-rays are done to check for these injuries. To stress a joint, doctors gently move the joint in a direction that is usually perpendicular to the joint's normal range of motion. If the joint feels very unstable, doctors suspect a dislocation (or a severe ligament injury).

If pain or muscle spasms interfere with the examination, the person may be given a pain reliever and/or muscle relaxant by mouth or injection, or a local anesthetic may be injected into the injured area. Or doctors immobilize the injured joint until the spasm goes away (usually after a few days) and then examine the joint.

Imaging tests used to diagnosis dislocations and other musculoskeletal injuries include

X-rays are useful for diagnosing dislocations, as well as fractures. X-rays are not useful for detecting injuries to ligaments, tendons, or muscles because they show only bones (and the fluid that collects around an injured joint).

X-rays are usually taken from at least two angles to show how the bones are aligned.

CT or MRI may be done to check for subtle fractures, which may accompany a dislocation.

Other tests may be done to check for other injuries that may result from a dislocation:

In the emergency department, doctors check for injuries that require immediate treatment.

If arteries are damaged, doctors surgically repair them unless the arteries are small and blood flow is not affected. The goal is to make sure the injured part is not deprived of blood. Compartment syndrome Compartment Syndrome Compartment syndrome is increased pressure in the space around certain muscles. It occurs when injured muscles swell so much that they cut off their blood supply. Pain in the injured limb increases... read more , if present, is treated.

Severed nerves are also repaired surgically, but this surgery can be delayed until several days after the injury if necessary. If nerves are bruised or damaged, they may heal on their own.

If the skin is torn, the wound is covered with a sterile dressing, and the injured person is given a vaccine to prevent tetanus Diphtheria-Tetanus-Pertussis Vaccine The diphtheria, tetanus, and pertussis vaccine is a combination vaccine that protects against these three diseases: Diphtheria usually causes inflammation of the throat and mucous membranes... read more and antibiotics to prevent infection. Also, the wound is cleaned, usually after a local anesthetic is used to numb the area.

Most moderate and severe dislocations, particularly very unstable ones, are immobilized immediately with a splint. This measure helps decrease pain and prevent further injury to soft tissues by unstable dislocations.

Pain is treated, typically with opioid pain relievers Opioid Pain Relievers Pain relievers (analgesics) are the main drugs used to treat pain. Doctors choose a pain reliever based on the type and duration of pain and on the drug's likely benefits and risks. Most pain... read more and/or nonsteroidal ani-inflammatory drugs (NSAIDs).

People with a dislocation may benefit from PRICE. PRICE refers to the combination of protection, rest, ice, compression (pressure), and elevation.

Protection helps prevent further injury that could worsen the original one. Typically, a splint or other device is applied.

Rest prevents further injury and may speed healing. People should limit their activity and avoid putting weight on and/or using the injured body part. For example, they may need to use crutches or to not participate in contact sports.

Ice and compression minimize swelling and pain. Ice is enclosed in a plastic bag, towel, or cloth and applied for 15 to 20 minutes at a time, as often as possible during the first 24 to 48 hours. Usually, compression is applied to the injury with an elastic bandage or a splint.

Elevating the injured limb helps drain fluid away from the injury and thus reduce swelling. The injured limb is elevated above heart level for the first 2 days.

After 48 hours, people can periodically apply heat (for example, with a heating pad) for 15 to 20 minutes at a time. Heat may relieve pain. However, whether heat or ice is best is unclear, and what works best may vary from one person to another.

Dislocations are moved back into their normal position (realigned, or reduced).

Reduction is usually done without surgery (called closed reduction), by manipulation—for example, by pulling and/or turning a limb. After reduction is done, doctors usually take x-rays to determine whether the injured parts are in their normal position.

Some dislocations must be realigned surgically (called open reduction Surgery A dislocation is complete separation of the bones that form a joint. In subluxation, the bones in a joint are partly out of position. Often, a dislocated joint remains dislocated until it is... read more ).

Usually, because reduction is painful, people are given pain relievers, sedatives, and/or an anesthetic Anesthesia Surgery is the term traditionally used to describe procedures (called surgical procedures) that involve manually cutting or stitching tissue to treat diseases, injuries, or deformities. However... read more before the procedure. The types of drugs that are used depend on how severe the injury is and how reduction is to be done:

After being realigned, the injury must be kept from moving (be immobilized).

Casts, splints, or slings are usually used after closed reduction of a dislocation. Some dislocated joints require only a sling or splint, which is applied after the joint is returned to its normal position.

Immobilization reduces pain and helps with healing by preventing further injury to surrounding tissues. Immobilization is helpful for most moderate or severe dislocations. Joints on both sides of the injury are immobilized.

If immobilization lasts too long (for example, for more than a few weeks in young adults), the joint may become stiff, sometimes permanently, and muscles may shorten (causing contractures) or shrink (waste away, or atrophy). Blood clots may develop. Such problems can develop quickly, and contractures can become permanent, usually in older people. Consequently, doctors encourage movement as soon as possible.

Casts are usually used for injuries that must be kept immobilized for weeks.

To apply a cast, doctors wrap the injured part in cloth, then apply a layer of soft cottony material to protect the skin from pressure and rubbing. Over this padding, doctors wrap dampened plaster-filled cotton bandages or fiberglass strips, which harden when they dry. Plaster molds well and is less likely to rub against the body. Fiberglass casts are stronger, lighter, and longer-lasting. After a week or so, the swelling goes down. Then, the plaster cast can sometimes be replaced with a fiberglass cast to fit the limb more snugly.

People who require a cast are given special instructions for its care. If a cast is not correctly cared for, problems can develop. For example, if the cast becomes wet, the protective padding under the cast may become wet, and drying it completely may be impossible. As a result, the skin can soften and break down, and sores may form. Also, if a plaster cast gets wet, it can fall apart and thus no longer protect and immobilize the injured area.

People are instructed to keep the cast elevated as much as possible at or above heart level, especially for the first 24 to 48 hours. They should also regularly flex and extend their fingers or wiggle their toes. These strategies help blood drain from the injured limb and thus prevent swelling.

Rarely, casts cause pain, pressure, or numbness that remains constant or worsens over time. Such pain must be reported to a doctor immediately. These symptoms may be due to a developing pressure sore Pressure Sores Pressure sores are areas of skin damage resulting from a lack of blood flow due to prolonged pressure. Pressure sores often result from pressure combined with pulling on the skin, friction,... read more or compartment syndrome Compartment Syndrome Compartment syndrome is increased pressure in the space around certain muscles. It occurs when injured muscles swell so much that they cut off their blood supply. Pain in the injured limb increases... read more . In such cases, doctors may have to remove the cast and apply another one.

A splint can be used to immobilize some stable dislocations, particularly if they need to be kept immobile for only a few days or less. During initial treatment, splints are also used to immediately immobilize moderate and severe dislocations, particularly very unstable ones, until the person can be evaluated thoroughly. Splints allow people to apply ice and to move more than a cast does.

A splint is a long, narrow slab of plaster, fiberglass, or aluminum applied with elastic wrap or tape. Because the slab does not completely encircle the limb, there is room for some expansion due to swelling. Thus, a splint does not increase the risk of developing compartment syndrome. Some injuries that eventually require a cast are first immobilized with a splint until most of the swelling resolves.

A sling by itself can provide some support. Slings can be useful when complete immobilization has undesirable effects. For example, if a shoulder is completely immobilized, the tissues around the joint may become stiff, sometimes within days, preventing the shoulder from moving (called frozen shoulder). Slings limit movement of the shoulder and elbow but allow movement of the hand.

A swathe, which is a piece of cloth or a strap, may be used with a sling to prevent the arm from swinging outward, especially at night. The swathe is wrapped around the back and over the injured part.

Occasionally, dislocations cannot be reduced using closed reduction, and surgery is required to realign the joint in its normal position. Once the joint has be realigned, additional surgery is often not necessary.

Sometimes surgery is required to treat fractures that accompany dislocations, to stabilize the joint, or to remove debris from the joint.