What are bone fractures and how are they classified?

What is a bone fracture?

A fracture is a break in the continuity of the bone. In other words, it is a change in the bone’s normal shape as a result of the application of a force greater than that which the bone can withstand. The category of fractures includes both highly comminuted fractures and small, barely perceptible cracks.

What causes a broken bone?

The causes of a broken bone can be quite varied. Orthopaedic surgeons often refer to this as the fracture mechanism. Though there are countless possible mechanisms, they usually fall into one of four categories:

• Direct trauma: The breakage is caused by a direct impact on the fracture point. Example: a hammer blow to a finger.
• Indirect trauma: The fracture occurs at a distance from the force that produced it. Example: when falling, an individual falls on their hand, but fractures their shoulder.
• Pathological fracture: Caused by a weakening of the bone due to a disease, such that even slight forces can break the bone. Example: a patient with bone cancer whose skeletal structure is weakening.
• Fatigue or stress fracture: Caused by repetitive and excessive strain placed on the bone, even though they may be of relatively low intensity. Example: toe fracture when a runner is training for a marathon.

Types of fracture according to the strength of the force that caused it

• High-energy fractures: Caused by the application of an intense and generally short-lived force. These fractures usually cause severe fragmentation and can severely affect the soft tissues that cover the bone. Example: traffic accident.
• Low-energy fractures: Caused by low-impact falls or incorrect or repetitive motions. They usually occur in people of advanced age or who have poor bone quality. Example: hip fracture due to osteoporosis.

Types of fracture according to soft tissue damage

• Closed fractures: There is no contact between the bone and the outside of the body.
• Open fractures: There is contact between the bone and the outside, i.e. there is a perforation of the skin and soft tissue that reaches the bone. Severity varies depending on the degree of damage, and risk of infection is much higher than in closed fractures.

Fracture pattern

The fracture pattern is the physical pattern that the breakage follows. There can be an infinite number of fracture patterns, but the most common patterns are those shown in this image.

• Transverse fracture: The break is perpendicular to the bone’s main axis.
• Oblique fracture: The break is at an angle to the bone’s main axis.
• Butterfly fracture: Typical when the bone undergoes bending forces. The break produces an intermediate wedge-shaped fragment.
• Spiral fracture: Usually the result of torsional forces and the break spirals around the bone.
• Segmental fracture: Fractures in which one bone segment is completely separated from the bone’s endpoints. The greatest risk they pose is loss of blood supply.
• Comminuted fracture: When the fracture has multiple fragments.
• Partial fracture: Breaks in non-essential or structural parts of the bone. One example is an avulsion fracture, which occurs when a major muscular force tears away the part of the bone to which the muscle is anchored.
• Bowing: These are not common and occur in children. It is not a complete break, but rather a plastic deformation of the bone.
• Impacted fracture: Fragments are jammed together when the bone undergoes a compressive force (especially in cancellous bone areas).
• Greenstick fracture: Typically found in children, this is an incomplete bone fracture with a shape that is reminiscent of a young branch being broken.

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