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Chris Colton - Orthopaedic Trauma Terms
Category: Health and Medicine > Orthopaedic Trauma
Date & country: 24/11/2007, UK
Words: 239


Stability, relative
An internal fixation construct that allows small amounts of motion in proportion to the load applied. This is the case with a fixation that depends exclusively on the stiffness of the implant (such as a nail, or plate, bridging a multifragmentary fracture segment). The residual deformation or displacement is inversely proportional to the stiffness …

Stable fixation
A fixation which keeps the fragments of a fracture in motionless adaptation during the application of controlled physiological forces. While a mobile fracture produces pain with any attempt to move the limb, stable fixation allows early painless functional rehabilitation. Thus, stable fixation minimizes irritation, which could eventually lead to fr…

Stiffness
The resistance of a structure to deformation. Under a given load, the higher the stiffness of an implant then the smaller its deformation, the smaller the displacement of the fracture fragments and the lower the strain generated in the repair tissue. Excessive tissue strain can interfere with healing. The stiffness of a structure is expressed as it…

Strain
Relative deformation of a material, for example, repair tissue. Motion at the fracture site in itself is not the important feature, but the resulting relative deformation, which is called strain (dL/L), of the healing tissues. As strain is a ratio (displacement of fragments divided by width of fracture gap), very high levels of strain may be presen…

Strain induction
Tissue deformation – among other things –may result in induction of callus. This would be an example of a mechanically induced biological reaction. For those reactions triggered by strain, such as callus formation and bone surface resorption, the concept of a lower limit of strain, the minimum strain, is to be considered.

Strain theory - Perren
With a small fracture gap, any movement will result in a relatively large change in length (i.e. high strain). If this exceeds the strain tolerance of the tissue, healing will not take place. If a larger fracture gap is subject to the same movement, the relative change in length will be smaller (i.e. less strain) and, if the critical strain level i…

Strain tolerance
This determines the tolerance of the repair tissues to mechanical conditions. No tissue can be formed under conditions of strain which exceed the levels of strain which at rupture the tissue by excessive elongation. Above such a critical level, tissues strain will disrupt the tissue once formed, or will prevent its formation.

Strength
The ability to withstand load without structural failure. The strength of a material can be expressed as ultimate tensile strength, as bending strength or as torsional strength. The local criterion for failure of bone, or of implants, is measured in units of force per unit area: stress, or (equivalent) deformation per unit length (strain), or elong…

Stress protection
This term, initially used to describe bone reaction to reduced functional load (Allgöwer et al. 1969) is used today mainly to express the negative aspects of any stress relief of bone. The basic assumption is that bone, deprived of its necessary functional stimulation by reducing its mechanical load, becomes less dense and so less strong (Wolff's l…

Stress riser
In any body subject to deformation, stress will be generated within its material. If any part of the body is weaker than the rest, there will be a concentration of stress (high mean stress) at this place. If an implant is notched by inappropriate handling, the area of damage will act as a stress riser and produce the risk of fatigue failure with cy…

Stress shielding
When internal fixation relies upon screws and plates, the stability of the construct is achieved mainly by the interfragmentary compression exerted by the lag screws. Lag screw fixation alone is very stable, but generally provides little security under functional load. A plate providing protection (or neutralization) is therefore often added. The f…

Subchondral
means beneath the cartilage

Sudeck's atrophy
One of the names given to Algodystrophy, Complex Regional Pain Syndrome, or Reflex Sympathetic Dystrophy

Superior
Literally above, or better than. In the anatomical position, if A is higher than, or above, B, then A is superior to B. The opposite is inferior.

Supination
The movement of rotating the forearm that causes the palm of the hand to face forward, that is restoring the hand to the anatomical position. Supination is also sometimes used to describe a movement of the foot into inclination toward the midline, otherwise called inversion; a supinated foot would bear more weight on its lateral border than on its …

Synovectomy
Excision of the synovial membrane. Synovial joint

Synovial membrane
the membrane lining the interior of a synovial (diarthrodial) joint, wherever the interior surface does not bear articular cartilage.

Systemic
Refers to any route for drug, or fluid, administration, other than via the gastro–intestinal tract, and usually by injection.

Tension band
An implant (wire, or plate) functioning according to the tension band principle: when the bone undergoes bending load, the implant, attached to the bone`s convex surface, resists the tensile force. The bone, especially the far cortex, is then dynamically compressed. The plate is able to resist very large amounts of tensile force, while the bone bes…

Threaded hole
Discussed in conjunction with Pilot hole

Tibial intercondylar eminence
The area of the proximal tibia lying between the medial and lateral tibial plateaux, which is non–articular and bears the attachments of the horns of the two menisci, and of the tibial ends of the anterior and posterior cruciate ligaments, to the anterior and posterior tibial spines.

Tibial spine
:See Tibial intercondylar eminence

Torus
A geometrical body in the shape of a solid ring that in cross section is circular, or elliptical – such as an inflated tyre inner tube. It is a term used in architecture to described the circumferential bulge seen at the top and bottom of classical columns. It has been applied to the “wrinkle� or “buckle� appearance seen in the compression cortex o…

Toxins
Poisonous chemicals. Some pathogenic organisms release powerful toxins when they multiply, and some when they die.

Trabecula
(pl. trabeculae) A solid bony strut of cancellous bone. Literally, a small beam, or bar

Tracheostomy
Surgical opening into the trachea (windpipe), usually to assist ventilatory support

Tract
Literally, a treatise or document (often religious), an anthem, an extent of territory, or an anatomical structure comprising mixed tissues organized to serve a specific physiological function (spino-thalamic tract, urinary tract, gastro-intestinal, etc.).

Trans-cortex
see Far Cortex

Transverse
Meaning across. Transverse bisection of the body in the anatomical position would divide it into upper and lower halves. Not the same as horizontal, which means parallel with the horizon. Thus if the body were lying flat on its back (supine), horizontal would be the same as the coronal plane (see above), but if the body were standing, in the anatom…

Union
. Strictly speaking, union means “as one� – as in marital union, a workers` union, even national groups, e.g. the United States.

Valgus
Deviation away from the midline in the anatomical position. Thus, genu valgum is a deformity at the knee where the lower leg is angled away from the midline (knock knee). By convention any deformity, or deviation, is described in terms of the movement of the distal part.

Varus
Deviation toward the midline in the anatomical position. Thus, genu varum is a deformity at the knee where the lower leg is angled toward the midline (bow leg). By convention any deformity, or deviation, is described in terms of the movement of the distal part.

Vascularity
That property of a tissue which reflects the extent to which it has, or does not have, a blood supply.

Vertical
Upright. Perpendicular to horizontal. Derives from vertex, meaning the top, as in the vertex of the skull.

Wave plate
. If the central section of a plate is contoured to stand off the near cortex over a distance of several holes, it leaves a gap between the plate and the bone, which (a) preserves the biology of the underlying bone, (b) provides a space for the insertion of a bone graft and (c) increases the stability because of the distance of the “waved� portion …

Wedge fracture
Fracture complex of the shaft of a long bone, with a third fragment, in which, after reduction, there is some direct contact between the main shaft fragments –see Butterfly fragment.

Working length
The distance between the two points of fixation (on either side of the fracture) between an implant, usually an intramedullary nail, and the bone.

Xenograft
A graft of tissue from an individual of one species (donor) to a recipient (host) of another species.

Zone of injury
The entire volume of bone and soft tissue damaged by energy transfer during trauma.