Bone fracture

A bone fracture is a medical condition in which a bonebecomes cracked, splintered, or bisected as a result of physical trauma.

Classification

Closed vs. open

In medicine, fractures are classified as closed or open (compound) and simple or multi-fragmentary (formerly comminuted).

• Closed fractures are those in which the skin is intact, while open (compound) fractures involve wounds that communicate with the fracture and may expose bone to contamination. Open injuries carry an elevated risk of infection; they require antibiotictreatment and usually urgent surgical treatment (debridement). This involves removal of all dirt, contamination, and dead tissue.

• Simple fractures are fractures that occur along one line, splitting the bone into two pieces, while multi-fragmentary fractures involve the bone splitting into multiple pieces. A simple, closed fracture is much easier to treat and has a much better prognosisthan an open, comminuted fracture. Other considerations in fracture care are displacement (fracture gap) and angulation. If angulation or displacement is 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.

Special considerations for children

In children, whose bones are still developing, there are risks of either a growth plate injury or a greenstick fracture.

• A greenstick fracture occurs because the bone is not as brittle as it would be in an adult, and thus does not completely fracture, but rather exhibits bowing without complete disruption of the bone's cortex.
• Growth plate injuries require careful treatment and accurate reduction to make sure that the bone continues to grow normally.
• Plastic deformationof the bone, in which the bone permanently bends but does not break, is also possible in children. These injuries may require an osteotomy(bone cut) to realign the bone if it is fixed and cannot be realigned by closed methods.

OTA classification (Orthopaedic Trauma Association)

Orthopaedic surgeons have devised an elaborate classification systemto describe the injury accurately and guide treatment. There are five parts to the code:

• Bone: Description of a fracture starts by naming the bone
  • (1) Humerus
  • (2) Radius/Ulna
  • (3) Femur
  • (4) Tibia/Fibula
  • (5) Spine
  • (6) Pelvis
  • (24) Carpus
  • (25) Metacarpals
  • (26) Phalanx(Hand);
  • (72) Talus
  • (73) Calcaneus
  • (74) Navicular
  • (75) Cuneiform
  • (76) Cuboid
  • (80) LisFranc
  • (81) Metatarsals
  • (82) Phalanx(Foot);
  • (45) Patella
  • (06) Clavicle
  • (09) Scapula
• Location: the part of the bone involved (e.g. shaft of the femur).
  • 1) proximal
  • 2) diaphyseal
  • 3) distal
• Type: It is important to note whether the fracture is simple or multifragmentary and whether it is closed or open.
  • A=simple fracture
  • B=wedge fracture
  • C=complex fracture
• Group: The geometry of the fracture is also described by terms such as transverse, oblique, spiral, or segmental.
• Subgroup: Other features of the fracture are described in terms of displacement, angulation and shortening. A stable fracture is one which is likely to stay in a good (functional) position while it heals; an unstable one is likely to shorten, angulate or rotate before healing and lead to poor function in the long term.

Other classification systems

There are other systems used to classify different types of bone fractures:

• "Neer classification" (PMID 9155417): humerusovervieweMedicine
• "Denis classification": spineGP Notebook
• "Seinsheimer's Classification": femurDuke

Bone response

The natural process of healing a fracture starts when the injured bone and surrounding tissues bleed. The blood coagulatesto form a blood clotsituated between the broken fragments. Within a few days blood vessels growinto the jelly-like matrix of the blood clot. The new blood vessels bring white blood cellsto the area, which gradually remove the non-viable material. The blood vessels also bring fibroblastsin the walls of the vessels and these multiply and produce collagenfibres. In this way the blood clot is replaced by a matrix of collagen. Collagen's rubbery consistency allows bone fragments to move only a small amount unless severe or persistent force is applied.

At this stage, some of the fibroblasts begin to lay down bone matrix(calcium hydroxyapatite) in the form of insoluble crystals. This mineralization of the collagen matrix stiffens it and transforms it into bone. In fact bone is a mineralized collagen matrix; if the mineral is dissolved out of bone, it becomes rubbery. Healing bone callusis on average sufficiently mineralized to show up on X-raywithin 6 weeks in adults and less in children. This initial "woven" bone does not have the strong mechanical properties of mature bone. By a process of remodelling, the woven bone is replaced by mature "lamellar" bone. The whole process can take up to 18 months, but in adults the strength of the healing bone is usually 80% of normal by 3 months after the injury.

Treatment

First aid for fractures includes stabilizing the break with a splintin order to prevent movement of the injured part, which could sever blood vesselsand cause further tissuedamage. Waxed cardboard splints are inexpensive, lightweight, waterproof and strong. Compound fractures are treated as open wounds in addition to fractures.

At the hospital, closed fractures are diagnosed by taking an X-rayphotograph of the injury.

Since bone healingis a natural process which will most often occur, fracture treatment aims to ensure the best possible function of the injured part after healing. Bone fractures are 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 plasteror fiberglasscastwhich holds the bones in position and immobilizes the joints 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 wrappingthem, which serves a similar function to making a cast. By allowing only limited movement, fixation helps preserve anatomical alignment while enabling callusformation, towards the target of achieving union.

Operative methods of treating fractures have their own risks and benefits, but usually surgery is done only if conservative treatment has failed or is very likely to fail. With some fractures such as hip fractures, surgery is offered routinely, because the complications of non-operative treatment include deep vein thrombosis(DVT) and pulmonary embolism, which are more dangerous than surgery. When a joint surface is damaged by a fracture, surgery is also commonly recommended to make an accurate anatomical reduction and restore the smoothness of the joint.

Infectionis especially dangerous in bones, due to their limited blood flow. Bone tissue is predominantly extracellular matrix, rather than living cells, and the few blood vessels needed to support this low metabolism are only able to bring a limited number of immune cellsto an injury to fight infection. For this reason, open fractures and osteotomies call for very careful antisepticprocedures and prophylacticantibiotics.

Image:K-Knie-z2.jpg Image:K-Fuss-z2.jpg Sometimes bones are reinforced with metal, but these fracture implantsmust be designed and installed with care. Stress shielding occurs when plates or screws carry too large of a portion of the bone's load, causing atrophy. This problem is reduced, but not eliminated, by the use of low-modulusmaterials, including titaniumand 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-chromiumalloy or stainless steelscrews), galvanic corrosionwill result. The metal ionsproduced can damage the bone locally and may cause systemic effects as well.

Bone fracture by location

• (S02): Skull fracture
  • (S021): Basilar skull fracture
• (S420): Clavicle fracture
• (S525): Distal radius fracture
• (S72): Hip fracture
• (S923): Jones fracture

See also

• Bone healing
• Fibrocartilage callus
• Osteoporosis
• Stress fracture
• Oral and Maxillofacial Surgery

External links

• First Aid for Fractures- From Wildernessmanuals.com
• Fracture and Dislocation Compendium of the Orthopaedic Trauma Associationde:Knochenbruch

fr:Fracture ko:?? it:Frattura (medicina) ja:?? nl:Botbreuk fi:Luunmurtuma pl:Z?amanie pt:Fratura

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Bone+fracture Wikipedia article Bone fracture.