A bone fracture is a medical condition in which a bone is cracked or broken. A fracture occurs when a force exerted against a bone is stronger than it can structurally withstand.
"You can break just about any bone in your body if the impact is strong enough," says orthopedic surgeon Dale Federico, MD, with Lehigh Valley Health Network. "High-speed traumas, such as car accidents, can shatter bones, but low-speed traumas like stepping off a curb can cause fractures too."
While many fractures are the result of high-force impact or stress, a bone fracture also may occur as a result of certain medical conditions that weaken the bones, such as osteoporosis or certain types of cancer. These type of so-called fragility fractures "occur with minimal impact, such as falling from a standing position," says hospitalist Steven Scott, MD, with Lehigh Valley Health Network. "They happen because the bone has become porous and brittle from loss of bone density."
Fractures are among the most common orthopedic problems. Doctors treat about 6.8 million fractures each year in the United States, and the average person can expect to sustain two fractures over the course of their lifetime.
Fractures of the extremities, such as arms, wrists, legs and ankles, are the most common and usually occur in men younger than age 45 and women older than 45. When women go through menopause and stop producing the female hormone estrogen, their rate of bone loss increases. This is why women are particularly susceptible to osteoporosis and subsequent fractures. The most common fracture prior to age 75 is a wrist fracture. In those over age 75, hip fractures become the most common broken bone.
Types of fractures
There are many different kinds of fractures. Below is a listing of the common fracture types that may occur:
- Compound fracture - When the bone exits and is visible through the skin, or a deep wound is present that exposes the bone, it is considered an open, or compound, fracture. The risk for infection is higher with this type of fracture.
- Simple fracture - During a closed or simple fracture, the bone is broken, but the skin is still intact.
- Comminuted fracture - In this type of fracture, the bone is shattered or broken in three or more pieces, and fragments are present at the fracture site. This type of complicated fracture tends to heal at a slower rate.
- Segmental fracture - In segmental fractures, the bone is fractured in two places, so there is a "floating" segment of bone.
- Compression fracture - A compression fracture occurs when two bones are forced against each other, crushing the bones and causing them to be wider or flatter in appearance. The bones of the spine, called vertebrae, are prone to this type of fracture. Elderly people, particularly those with osteoporosis, are at increased risk.
- Spiral fracture - A spiral fracture occurs when the fracture runs around the bone axis. This is common in a twisting injury.
- Stress fracture - A stress fracture or hairline 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 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.
- Pathological fracture - In a pathological fracture, bones weakened by various diseases (such as osteoporosis or cancer) tend to break with very little force.
- Greenstick fracture - In a greenstick fracture, the bone sustains a small, slender crack. This type of fracture is more common in children, due to the comparative flexibility of their bones.
- Bow fracture - Also common in children, a bow fracture occurs when the bone is bent but not broken.