Fracture (bone)
|
|
A fractured bone in a living person is typically treated by restoring the fractured pieces of bone to their natural positions (if necessary), and maintaining those positions while the bone heals. To this end, a fractured limb is usually immobilized with a plaster or fiberglass cast which fixes the healthy bones above and below the fracture. In some cases surgical nails, screws, plates and wires are used to hold the fractured bone together more directly. Occasionally smaller bones, such as toes, may be treated without the cast, by buddy wrapping them, which serves a similar function to making a cast. By allowing only limited movement, fixation helps preserve anatomical alignment while enabling callus formation, towards the target of achieving union. Operative methods of treating fractures have their own risks and benefits, but usually surgery is done only if the risk of conservative treatment outweighs the potential benefit of an operation.
| Contents |
Classification
In medicine, fractures are classified as closed or open (compound) and simple or comminuted. Closed fractures are fractures where the skin is intact and there is no bone poking out while open (compound) fractures involve wounds that expose bone. Open injuries carry an elevated risk of infection and at minimum require antibiotic treatment, and in fact many require urgent surgical treatment. The only method of accurately diagnosing a closed fracture is by having an X-Ray photograph taken of the injury. Simple fractures are fractures that occur along one line, splitting the bone into two pieces while comminuted fractures involve the bone splitting into multiple pieces. A simple, closed fracture is much easier to treat and has a much better prognosis than an open, comminuted fracture. Other considerations in fracture care are displacement (fracture gap) and angulation. If angulation or displacement are large, reduction (manipulation) of the bone may be required and, in adults, frequently requires surgical care. These injuries may take longer to heal than injuries without displacement or angulation. In children, whose bones are still developing, there is the risk of a greenstick fracture. This type of fracture occurs because the bone is not as brittle as it would be in an adult, and thus does not completely fracture, but exhibits bowing without complete disruption of the cortex. Plastic deformation of the bone is also possible in children, a situation in which the bone permanently bends but does not break. These injuries may require an osteotomy (bone cut) to realign the bone if it is fixed and cannot be realigned by closed methods.
Bone response
Infection is especially dangerous in bones, due to limited blood flow. Bone tissue is predominantly extracellular matrix, rather than living cells, and the blood vessels needed to support this low metabolism are only able to bring a limited number of immune cells to an injury. For this reason, open fractures and osteotomies call for very careful antiseptic procedures and (as mentioned above) propylactic antibiotics.
Fracture implants should also be designed and installed with care. Stress shielding occurs when plates or screws carry too large a portion of the bone's load, causing atrophy. This problem is reduced, but not eliminated, by the use of low-modulus materials, including titanium and its alloys. The heat generated by the friction of installing hardware can easily accumulate and damage bone tissue, reducing the strength of the connections. If dissimilar metals are installed in contact with one another (i.e., a titanium plate with cobalt-chromium alloy or stainless steel screws), galvanic corrosion will result. The metal ions produced can damage the bone locally and may cause systemic effects as well.
See also
External links
- First Aid for Fractures (http://www.wildernessmanuals.com/manual_4/chpt_4/index.html) - From Wildernessmanuals.comde:Knochenbruch