Definition : Dislocation

Dislocation is a complete loss of contact of the joint surfaces of a joint, usually caused by a sudden trauma such as a fall or impact. It is an orthopedic emergency that requires prompt intervention to prevent permanent damage to surrounding ligaments, tendons, muscles and nerves. Signs of dislocation include sudden pain, functional impotence and joint deformity. Treatment often involves reduction of the joint, which may be accomplished by external maneuvers or may require surgery.

Dislocations are often caused by a sudden trauma to the joint, such as an impact or a fall. A joint dislocation can cause damage to surrounding ligaments, tendons, muscles and nerves. Dislocations can occur in any major (shoulder, knee, etc.) or minor (toes, fingers, etc.) joint.

The most common mechanism is a fall (dislocation of the shoulder by falling on the hand), or an external stress on the limb such as a wrench.  The limb acts as a lever that amplifies the effort on the joint.

• The mechanism: shock, fall;
• The pain, sudden and localized;
• Functional impotence: it is extremely painful or impossible to perform certain movements even with assistance;
• The deformation: asymmetry of the joints (the left joint does not look like the right one);
• The perception by the patient of a cracking sound (also valid for a severe sprain);
• The perception by the patient of a snap;
• History of dislocation: when a joint has been dislocated, it is weakened and therefore the appearance of another dislocation in the same place is likely.

These signs are not specific and may also indicate a sprain or fracture. A careful clinical examination by a health professional will make the difference. On the other hand, some dislocations present lesser symptoms, for example in the case of a person with flexible joints (child, recurrence of a dislocation).

The only test that can unambiguously indicate whether or not a dislocation exists is an x-ray.

A vascular and neurological assessment distal to the injury.

Inspection for deformity, swelling, and bruising.

Light palpation looking for tenderness, crepitus, and gross defects in bones or tendons.

Some findings may indicate a fracture or other musculoskeletal injury.

Deformity may indicate dislocation, subluxation (partial separation of the bones of a joint), or fracture.

Swelling is often a sign of a fracture or other significant musculoskeletal injury, but it may take several hours to develop. If there is no swelling within that time, the fracture is unlikely. For some fractures (e.g., loop fractures, small non-displaced fractures), swelling may be subtle, but it is rarely absent.

Tenderness accompanies almost all musculoskeletal injuries, and for many patients, palpation of any area around the injured area causes discomfort. However, a noticeable increase in tenderness in a localized area (point tenderness) suggests a fracture.

Crepitus (a characteristic palpable and/or audible creaking sound produced when the joint is moved) may be a sign of fracture.

The idea of splinting is to minimize the movement of damaged bones or joints.

External pressure can make already damaged joints even more unstable. Whether the damage is to hard tissue such as bone or to complex soft tissue such as that of a joint, the treatment is based on immobilization.

To prevent external pressure from aggravating the damage, it is necessary to immobilize the affected area, i.e. splint it. It is vital to immobilize as much as possible to reduce the risk of further injury.

A limb splint will not work if you do not completely encapsulate the injury in the splint. This means that you must immobilize the joints above and below the fracture. Because a moving wrist or elbow puts pressure on the bones of the forearm, a dislocation in this area also requires immobilization of the wrist and elbow.

In the case of a dislocation or sprain, not only the joint, but also the structures (usually the bones) on either side of the joint must be immobilized. In the case of a knee, for example, the thigh (femur) and lower leg (tibia and fibula) will need to be immobilized with a splint to prevent the knee from moving. Some say that dislocations are actually much more painful than fractures, and that the patient is likely not to move the extremity without any encouragement.

The reason for splinting an injury, especially a limb, is not to heal it. 

A first aid splint is used to get the victim to the hospital or doctor. Sometimes a splint can make it easier to move the injured victim, either by allowing the victim to be moved without aggravating the injury, or by allowing the victim to move on his or her own.

While helping the victim get to the doctor, it is important not to make the situation worse. First and foremost, splints should not aggravate the injury to the extremity. Proper immobilization usually prevents worsening of the injury, which can be measured by assessing the function of the extremity. Circulation, sensation, and motion are the hallmarks of function in all extremities.

Blood flow to the injured area (circulation) can be disrupted if the surrounding tissue is damaged, including the blood vessels. Anything strong enough to break a bone is strong enough to disrupt arteries, veins and capillaries.

To assess circulation, palpate the limb and its twin (if the right arm is broken, compare the right arm to the left arm) to check for heat. The injured end should be as warm as the opposite end. If it is cooler, it is a sign that blood flow to the area is compromised.

Compare the color. Purple, blue, mottled or pale are all signs of decreased blood flow to the extremity.

If you know how to take a pulse, compare the pulses in the extremities of the limbs. If the pulse in the injured extremity is absent or very weak, it is an indicator of circulatory problems.

The gold standard has always been to use capillary refill (apply gentle pressure to the fingernails or toenails to "bleach" or extract color, then release the pressure; color is supposed to return in less than two seconds), but there is very little evidence that capillary refill is a reliable measure.

Presumed open fractures require sterile dressings

Sensation is the second measure of function. In this case, the test is simple: "Can you feel this?"

Without letting the victim see which toe or finger you are touching, ask him or her to tell you which one it is (keep it simple and use the pinkie or big toe, as middle toes and fingers are not always easy for patients to describe). If the victim does not feel you touch an extremity (or does not know what you are touching), it is a sign that the extremity is not getting enough blood flow, resulting in nerve dysfunction, or that there is actual nerve damage.

The final measure of function is movement. Can the victim move the extremity?

A loss of motion is an indicator of loss of circulation, motor nerve damage, or structural failure. Bones and muscles are just levers and pulleys designed to make things move in a certain way. If you break the support structure, sometimes the machine doesn't move the way it's supposed to.

Most moderate and severe fractures, especially those that are obviously unstable, are immediately immobilized with a splint (immobilization with a non-rigid or non-circumferential device) to decrease pain and prevent further soft tissue damage from unstable fractures. 

Immobilization decreases pain and facilitates healing by preventing further injury and maintaining alignment of the fracture ends.

Be sure to assess limb function at least twice. Check once before any treatment is applied and then again after splinting. If any of the functions (circulation, sensation and movement) have disappeared or worsened, try adjusting or even removing the brace. Loss of function is a significant problem that can lead to permanent damage if not addressed.

Fractures in different areas of the body require different techniques to immobilize them. Starting at the top, let's look at the different types of slings and where they can be used most effectively.

Injuries to the shoulder girdle (clavicle and scapula) or upper arm (humerus) can only be treated properly with a sling and tape. Forearm injuries must be splinted with one of the techniques below, but can still be placed in a sling to help manage the injury. It is also easier for the patient to move if the splint is placed in a sling.

A sling is basically a hammock for your arm. It helps support the weight of the arm rather than letting it hang and pull on injured bones and tissues. A sling is used to attach the arm, still in the sling, to the patient's body.

Slings can be commercially made (typically after surgery) or they can be made from a triangular bandage or even a long shirt tail.

The most economical of all commercial splints is the cardboard splint. A cardboard splint is exactly as the name suggests, a cardboard splint designed for first aid. Cardboard splints can also be made from any type of thick-walled box. With a piece of cardboard, a roll of tape, a towel and a pair of scissors, almost any extremity fracture can be splinted.

Cardboard splints can be cumbersome and difficult to apply, and they don't work if they get wet. In addition, a cardboard splint can make it difficult to visualize an injured limb in order to reassess its function or to treat open wounds and control bleeding.

Malleable aluminum splints usually come in the form of a roll, but they can also come in a flat, padded version. Aluminum splints can be shaped very easily to fit an injured limb and they hold their shape in the rain. They are more expensive than cardboard, but take up much less space and can be applied more easily and with much less bulk once they are attached.

With practice, aluminum splints can be applied quickly, without hiding the end as much as a cardboard splint. Aluminum splints are also commonly used for finger splints and are sold in small, ready-to-use packages.

Ankle injuries can be properly repaired with a simple pillow and a roll of tape. A suitable pillow (down is not really suitable for this) can be wrapped around the foot of the injured ankle and taped around the leg. This effectively creates a soft "boot" to hold the injured ankle.

A pillow large enough can also be used to splint an arm or leg, although this is not ideal.

James M. Madsen , MD, MPH: February 2021 "Overview of Incidents Involving Mass-Casualty Weapons" https://www.merckmanuals.com/en-ca/professional/injuries-poisoning/mass-casualty-weapons/overview-of-incidents-involving-mass-casualty-weapons [Last accessed January 20, 2023]

Rod Brouhard, EMT-P: November 18, 2021 "How To Treat an Avulsion or Degloving" https://www.verywellhealth.com/how-to-treat-an-avulsion-1298913 [Last accessed January 20, 2023]