Bone Fixator
X-Ray of tibia with an intramedullary nail (IML), ref:www.hwbf.org

Bone Fracture Fixation Overview (2/3)

previous page ...two groups: invasive and non-invasive. Non-invasive stabilization methods are suitable for treating relatively simple bone fractures. They provide the least control over the mechanical environment of the fracture, because they have no direct contact with the skeletal system. Positional control of the broken bone segments is performed via surrounding tissues and therefore is neither very accurate nor versatile. Non-invasive stabilization was one of the first methods used in medicine. Original methods included the use of a wooden bar/splint attached along the side of the anatomy using flexible ties. This type of method was not very effective because the wooden component did not follow the bone geometry and as a result, often badly-aligned union was achieved. A more advanced version of this type of stabilization has replaced the wooden component by a plaster cast. The plaster cast more successfully mimicked the shape of the bones and its surrounding tissues. If a long plaster cast was used it was possible to avoid unwanted angulations, however, there was very poor control over the length of the bone, axial rotation and position of the fractured bone segments. The advantage of non-invasive fixators is that they do not cause any direct damage to the anatomy; they are easy to assemble and use. They also avoid infection. However, there is a limit to control of the fracture due to the soft tissue properties and presence. The common type of healing for fractures stabilised with non-invasive fixation devices is external bridging callus.

Examples of invasive fracture fixation methods. a) plate and screws, b) intramedullary nail fixed with screws inside the bone, c) unilateral bar connected to bone via half-pins, d) TSF ring fixator with two accessory rings and connection to bone via 8 fine wires.
Figure 2. Examples of invasive fracture fixation methods. a) plate and screws, b) intramedullary nail fixed with screws inside the bone, c) unilateral bar connected to bone via half-pins, d) TSF ring fixator with two accessory rings and connection to bone via 8 fine wires.

Unlike to non-invasive fixators, invasive fixators penetrate the anatomy in order to establish direct connection with the skeletal system. They can be grouped into: internal and external, Figure 2.

Examples of internal fixators would be intramedullary nails and plates. Those fixators are implanted into... continue reading on the next page...