Introduction to fracture

Bones form the skeleton of the body and allow the body to be supported against gravity and to move and function in the world. Bones also protect some body parts, and the bone marrow is the production center for blood products.

Bone is not a stagnant organ. It is the body's reservoir of calcium and is always undergoing change under the influence of hormones. Parathyroid hormone increases blood calcium levels by leeching calcium from bone, while calcitonin has the opposite effect, allowing bone to accept calcium from the blood.

What causes a fracture?

When outside forces are applied to bone it has the potential to fail. Fractures occur when bone cannot withstand those outside forces. Fracture, break, or crack all mean the same thing. One term is not better or worse than another. The integrity of the bone has been lost and the bone structure fails.

Broken bones hurt for a variety of reasons including:

• The nerve endings that surround bones contain pain fibers and and these fibers become irritated when the bone is broken or bruised.
  
  
• Broken bones bleed, and the blood and associated swelling (edema) causes pain.
  
  
• Muscles that surround the injured area may go into spasm when they try to hold the broken bone fragments in place, and these spasms cause further pain.

Often a fracture is easy to detect because there is obvious deformity. However, at times it is not easily diagnosed. It is important for the physician to take a history of the injury to decide what potential problems might exist. Moreover, fractures don't always occur in isolation, and there may be associated injuries that need to be addressed.

Fractures can occur because of direct blows, twisting injuries, or falls. The type of forces on the bone may determine what type of injury that occurs. Descriptions of fractures can be confusing. They are based on:

• where in the bone the break has occurred,
  
  
• how the bone fragments are aligned, and
  
  
• whether any complications exist.

The first step in describing a fracture is whether it is open or closed. If the skin over the break is disrupted, then an open fracture exists. The skin can be cut, torn, or abraded (scraped), but if the skin's integrity is damaged, the potential for an infection to get into the bone exists. Since the fracture site in the bone communicates with the outside world, these injuries need to be cleaned out aggressively and many times require anesthesia in the operating room to do the job effectively.

Next, there needs to be a description of the fracture line. Does the fracture line go across the bone (transverse), at an angle (oblique) or does it spiral? Is the fracture in two pieces or is it comminuted, in multiple pieces?

Finally, the fracture's alignment is described as to whether the fracture fragments are displaced or in their normal anatomic position. If the bones fragments aren't in the right place, they need to be reduced or placed back into their normal alignment.

What are common types of fractures?

Stress fracture

A stress fracture is an overuse injury. Because of repeated micro-trauma, the bone can fail to absorb the shock that is being put upon it and become weakened. Most often it is seen in the lower leg, the shin bone (tibia), or foot. Athletes are at risk the most, because they have repeated footfalls on hard surfaces. Tennis players, basketball players, jumpers, and gymnasts are typically at risk. A March fracture is the name given to a stress fracture of the metatarsal or long bones of the foot. (It is named because it often occurs in soldiers who are required to march long distances.)

Diagnosis is made by history and physical exam, though on occasion a bone scan may be done to confirm the diagnosis.

Treatment is conservative, rest, ice, and anti-inflammatory medication like ibuprofen. These fractures can take six to eight weeks to heal (as long as the fracture can be seen on x-ray). Trying to return too quickly can cause re-injury, and may also allow the stress fracture to extend through the entire bone.

Shin splints may have very similar symptoms as a stress fracture of the tibia but they are due to inflammation of the lining of the bone, called the periosteum. Shin splints are caused by overuse, especially in runners, walkers, dancers, including those who do aerobics. Muscles that run through the periosteum and the bone itself may also become inflamed.

Treatment is similar to a stress fracture and physical therapy can be helpful.

Compression fracture

As people age, there is a potential for the bones to develop osteoporosis, a condition where bones lose their calcium content. This makes bone more susceptible to breaking. One such type of injury is a compression fracture to the spine, most often the thoracic or lumbar spine. Since we are an upright animal, if the bones of the back are weaker than the force of gravity these bones can crumple. Pain is the major complaint, especially with movement.

Compression injuries of the back may or may not be associated with nerve or spinal cord injury. An x-ray of the back can reveal the bone injury, however, sometimes a CT scan or MRI will be used to insure that no damage is done to the spinal cord.

Treatment includes pain medication and often a back brace. Some compression fractures can also be treated with vertebroplasty. Vertebroplasty involves inserting a glue-like material into the center of the collapsed spinal vertebra in order to stabilize and strengthen the crushed bone. The glue (methylmethacrylate) is inserted with a needle and syringe through anesthetized skin into the midportion of the vertebra under the guidance of specialized x-ray equipment. Once inserted, the glue soon hardens, forming a cast-like structure with the locally broken bone.

Rib fracture

The ribs are especially vulnerable to injury and are prone to breaking due to a direct blow. Rib x-rays are rarely taken as it doesn't matter if the rib is broken or just bruised. A chest x-ray is usually taken to make certain there is no collapse or bruising of the lung.

When we breathe, it is like a bellows. We inhale air into our lungs and the ribs move out and the diaphragm moves down. When a person has a rib injury, the pain associated with it makes breathing difficult, and the person has a tendency to not take deep breaths. If the lung underlying the injury does not expand, it is at risk for infection. The person is then susceptible to pneumonia (lung infection),which is characterized by fever, cough, and shortness of breath.

As opposed to other parts of the body that can rest when they are injured, it is very important to take deep breaths to prevent pneumonia when rib fractures are present. The treatment for bruised and broken ribs is the same: ice to the chest wall, ibuprofen as an anti-inflammatory, deep breaths and pain medication. Even if all goes well, there will be significant pain for four to six weeks.

With lower rib fractures, there may be concern about organs in the abdomen that the ribs protect. The liver is located under the ribs on the right side of the chest, and the spleen under the ribs on the left side of the chest. Many times your doctor may be more worried about abdominal injury than about the broken rib itself. Ultrasound or CT scan may help diagnosis intra-abdominal injuries.

Skull fracture

With the wide availability of CT scans, skull x-rays are rarely taken to diagnose head injury. If a head injury exists, the physician will feel or palpate the scalp and skull to determine if there may be a skull fracture. He will also look into the ears to see if there is blood behind the ear drumm and he will also complete a neurologic examination.

The skull is a flat, compact bone and it takes significant force to break it. If a skull fracture exists, there is an increased likelihood of bleeding in the brain, especially in children. There are guidelines that are available to decide whether a CT scan is indicated (needed).

Minor head injury is defined as witnessed loss of consciousness, definite amnesia, or witnessed disorientation in patients with a GCS (Glasgow Coma Score) score of 13-15. With minor head injury, the following risk groups are considered when evaluating need for CT brain scan:

High risk for potential neurosurgical operation

• Abnormal neurologic exam within two hours after injury
  
  
• Suspected open or depressed skull fracture
  
  
• Any sign of basal skull fracture (blood behind the ear drum, blackened eyes, clear fluid running from the ears, or bruising behind the ear)
  
  
• Vomiting - two episodes
  
  
• 65 years of age or older

Medium risk (for brain injury on CT)

• Amnesia before impact - more than 30 minutes
  
  
• Dangerous mechanism (pedestrian struck by motor vehicle, occupant ejected from motor vehicle, fall from height greater than 3 feet or five stairs)

Fracture in children

Children can break bones and yet have normal x-rays. Fractures appear as clear lines through the bone on an x-ray through the bone. If calcium hasn't yet accumulated in the repairing bone, the break may not be apparent. This lack of calcification happens in two ways.

1. Bones mature at different times in a child's development and while the bony structure is there, it may have more cartilage than calcium.


2. The second situation is associated with growth plates. Each bone has an area where cell activity is maximal and where the bone grows. These areas appear as lucent lines on x-ray. It may be one of the weaker points in the bone as well, and a fracture through the growth plate may not be seen.

The doctor needs to match the history and physical exam with what is seen on x-ray to make to a diagnosis. Sometimes, the child is placed in a cast for a period of time to protect the broken limb. As fractures heal, the body lays down extra calcium as building material and then remodels it to normal shape. After 7-10 days, there may be evidence on x-ray of the healing calcium to confirm the fracture.

Growth plate fractures are classified by Salter-Harris category. When a break occurs through the growth plate, it can involve different parts of the bone on each side of the plate. It is important that these fractures are aligned properly so that the bone grows properly as the child ages. For more, please read the Growth Plate Fractures in Children article.

Children are more flexible than adults until the calcium completely solidifies their bone. If you think of an arm or leg bone as tubular, sometimes only one side of the bone breaks, just like an immature branch on a tree. This is referred to as a greenstick fracture, and may need to be "set" so that it heals properly. Sometimes the bones can bend but not break because they are so pliable. This is called a plastic deformity and again will need to be set or aligned to allow proper healing.

How is a fracture diagnosed?

When you arrive for medical care, the doctor will take a history of the injury. Where, when, and why did the injury occur? Did the person trip and fall, or did they pass out before the fall? Are there other injuries that take precedence over the fracture? For example, a person who falls and hurts their wrist because they had a stroke or heart attack will have their fracture care delayed to allow care for the life threatening illness. The injured area will be examined and a search will happen for potential associated injuries. These include damage to skin, arteries and nerves.

Pain control is a priority and many times, pain medication will be prescribed before the diagnosis is made. If the doctor believes that an operation is likely, pain medication will be given through an intravenous (IV) line or by an injection into the muscle. This allows the stomach to remain empty for potential anesthesia.

A decision will be made whether x-rays are required, and which type of x-ray should be taken to make the diagnosis and better assess the injury. There are guidelines in place to help doctors decide if an x-ray is necessary. Some include the Ottawa ankle and knee x-ray rules.

The body is three dimensional, and plain film x-rays are only two dimensional. Therefore, two or three x-rays of the injured areas may be taken in different positions and planes to give a true picture of the injury. Sometimes the fracture will not be seen in one position, but is easily seen in another.

There are areas of the body where one bone fracture is associated with another fracture at a more distant part. For example, the bones of the forearm make a circle and it is difficult to break just one bone in that circle. Think of trying to break a pretzel in just one place, it is difficult to do. Therefore broken bones at the wrist may be associated with an elbow injury. Similarly, an ankle injury can be accompanied by a knee fracture. The doctor may x-ray areas of the body that don't initially appear to be injured.

Occasionally, the broken bone isn't easily seen, but there may be other signs that a fracture exists. In elbow injuries, fluid seen in the joint on x-ray is an indicator of a subtle fracture. And in wrist injuries, fractures of the scaphoid or navicular bone may not show up on x-ray for one to two weeks, and diagnosis is made solely on physical examination with swelling and tenderness over the snuffbox at the base of the thumb.

In children, bones may have numerous growth plates that can cause confusion when reading an x-ray. Sometimes, the doctor will choose to x-ray the opposite arm or leg to determine what normal is for the child before deciding whether a fracture exists.

What is the treatment of a fracture?

Initial treatment for fractures of the arms, legs, hands and feet in the field include splinting the extremity in the position it is found, elevation and ice. Immobilization will be very helpful with initial pain control. For injuries of the neck and back, many times, first responders or paramedics may choose to place the injured person on a long board and in a neck collar to protect the spinal cord from potential injury.

Once the fracture has been diagnosed, the initial treatment for most limb fractures is a splint. Padded pieces of plaster or fiberglass are placed over the injured limb and wrapped with gauze and an elastic wrap to immobilize the break. The joints above and below the injury are immobilized to prevent movement at the fracture site. This initial splint does not go completely around the limb. After a few days, the splint is removed and replaced by a circumferential cast. Circumferential casting does not occur initially because fractures swell (edema). This swelling would cause a build up of pressure under the cast, yielding increased pain and the potential for damage to the tissues under the cast.

Surgery

Surgery on fractures are very much dependent on what bone is broken, where it is broken, and whether the orthopedic surgeon believes that the break is at risk (for staying where it is) once the bone fragments have been aligned. If the surgeon is concerned that the bones will heal improperly, an operation will be needed. Sometimes bones that appear to be aligned normally are splinted, and at a recheck appointment, are found to be unstable and require surgery.

Surgery can include closed reduction and casting, where under anesthesia, the bones are manipulated so that alignment is restored and a cast is placed to hold the bones in that alignment. Sometimes, the bones are broken in such a way that they need to have metal hardware inserted to hold them in place. Open reduction means that, in the operating room, the skin is cut open and pins, plates, or rods are inserted into the bone to hold it in place until healing occurs. Depending on the fracture, some of these pieces of metal are permanent (never removed), and some are temporary until the healing of the bone is complete and surgically removed at a later time.

References: Stiell IG, et al. The Canadian CT head rule for patients with minor head injury. Lancet May 5, 2001;357:1391-6. Stiell IG, et al. The Canadian CT head rule for patients with minor head injury. Lancet May 5, 2001;357:1391-6.

sourceLast Editorial Review: 8/7/2007

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