Why do fractures occur

fracture (Broken bone)

The human skeleton is made up of 206 different bones. They can break if subjected to too much stress. Most fractures (broken bones) are caused by force.

Short version:

  • A fracture is an abnormal break in a bone.
  • A bone fracture is usually caused by direct or indirect violence.
  • Repeated moderate application of force can also lead to breakage. One then speaks of a fatigue break.
  • A distinction is made among other things between open and closed fractures. If the fracture is open, the soft tissues are severed and the bone is exposed.
  • The symptoms of a fracture depend heavily on the type and location.
  • A fracture can be treated conservatively and surgically.

Bones are among the hardest and most resilient parts of the body. The bone structure consists of a mineral, an elastic and a connective tissue component. In addition, blood vessels and nerves run through the bone. Depending on the age of the person, the composition varies:

  • In children, elastic components predominate. The bones are therefore more likely to "bend" ("green wood breakage") than to break.
  • In adults, the ratio between mineral, elastic and connective tissue components is balanced.
  • In older people, the elastic and connective tissue components decrease, the bone becomes brittle and splinters more easily.

How does a bone break occur?

A fracture is an abnormal break in a bone or bone structure. If a bone is stressed beyond its elastic limit, it can break. Usually this happens through massive violence. Typical causes of a broken bone are falls, blows or a heavy impact. However, repeated medium force exposure (e.g. in marathon runners) can also lead to a break. In this case one speaks of a stress fracture.

Pathological changes (e.g. osteoporosis, bone tumor) can increase the risk of a bone fracture. In the presence of osteoporosis, the bone has a lower mineral content and is weakened as a result. Even minor accidents can lead to broken bones.

What types of bone fractures are there?

Fractures are differentiated according to various criteria:

  • Localization: e.g. skull fracture, thigh fracture, etc.
  • Fracture shape: Transverse fracture, longitudinal fracture, oblique fracture, spiral fracture
  • Number of bone fragments: Single-fragment fracture, multiple-fragment fracture, comminuted fracture
  • Mechanical cause: Torsional fracture, avulsion fracture, shear fracture, burst fracture, fatigue fracture (stress fracture), compression fracture, pathological fracture (spontaneous fracture)
  • Position of the fracture ends: displaced (displaced) or undisplaced (undisplaced) fracture
  • Extent: complete or incomplete fracture
  • Joint involvement: intra-articular (inside the joint) or extra-articular fracture (outside the joint)
  • Concomitant soft tissue injury: open or closed fracture (in an open fracture the soft tissues are severed, the bone is exposed)

What are the symptoms of a broken bone?

The symptoms of a broken bone depend heavily on the type and location. The signs of fatigue fractures are often less pronounced, which is why they are often mistaken for a sprain or bruise at the beginning. A distinction is made between safe and unsafe Fraktur signs. Uncertain signs of a fracture can also have another cause, such as a bruise or infection.

Unsafe fracture signs:

  • Pain
  • swelling
  • Hematomas
  • Restriction of movement

Safe fracture signs:

  • Misalignments (e.g. of an extremity)
  • Rubbing noises (crepitation)
  • abnormal mobility (e.g. in the fracture area of ​​a lower leg fracture)
  • visible bone fragments (open fracture)

How is a broken bone diagnosed?

The classic method of diagnosing a fracture is an X-ray examination in two planes. The images only show the bones, not the tendons, muscles or ligaments. With almost every break, the position and number of the fragments can be identified. X-rays also show whether a joint is affected or the fracture is displaced. Non-displaced fractures (comparable to a "crack in the plate") can sometimes not be diagnosed using the X-ray image. In such cases, computed tomography (CT) and magnetic resonance imaging (MRI) can be used to confirm the diagnosis.

+++ More on the topic: X-ray +++

How is a broken bone treated?

The treatment of a fracture depends on several factors. Basically, one can differentiate between conservative and surgical treatment (osteosynthesis).

Many fractures do not require surgery. In particular, fractures that have not been displaced or those that are stable after setting up, i.e. show no tendency to move again (dislocation), are treated without surgery (conservative). The fracture is brought into the anatomically correct position (reduction) and immobilized with a plaster cast or plastic bandage or a splint. How long this takes depends on the extent of the injury. On average, a fracture heals in about six weeks.

When are fractures operated on?

Some fractures require surgery, such as ...

  • If they shift slightly again, with or without a device, and if the malposition is likely to result in a poor functional result after the healing process is complete: Here an early, definitive restoration can take place.
  • if they heal slowly: e.g. in a scaphoid fracture. With an operation, the patient can be recovered much faster. A longer plaster of paris treatment is avoided and you can start a physiotherapy exercise treatment early on.
  • if there are open fractures: the soft tissue cover must be restored here.

Plates and screws are used in various strengths that are adapted to the respective bone. Certain broken bones are treated with individual screws, intramedullary nails, drill wires and special implants.

+++ More on the subject: scaphoid fracture +++

What happens after the therapy?

As soon as the fracture has healed so well that it is resilient again, mobilization should begin gradually. The aim is to restore the original function and prevent further muscle breakdown. In most cases, physical therapy can produce good results.

What complications can arise?

Most fractures heal well with no complications. In rare cases, a break in the plaster of paris "slips" off. It may then have to be set up or operated again.

Occasionally the bone does not heal and a "false joint" (pseudarthrosis) forms. If the pseudarthrosis causes discomfort, it must be operated on.

An infection of the bone is feared, but at the same time very rare. It occurs mainly after open fractures and requires extensive treatment that can take several months.

In patients who wear plaster of paris, pressure sores sometimes lead to circulatory disorders. In addition to skin damage, nerve damage is also very rare.

Prolonged immobilization poses a risk of thrombosis (occlusion of the veins), especially with hip, pelvic and leg fractures. As a preventive measure, thrombosis prophylaxis is carried out for the duration of the immobilization.

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Authors:
Dr. med. Martin Schäfer, specialist in surgery (first author 2008), Silke Brenner (2020)
Medical review:
Dr. David Böckmann
Editorial editing:
Mag. Julia Wild

Status of medical information:

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ICD-10: S46.2