If there is a term that you cannot find here please email me.
Alternatively, consult Medline online medical dictionary at http://www.nlm.nih.gov/medlineplus/mplusdictionary.html
Abduction: Movement of a part away from the midline, e.g.
abduction at the shoulder moves the arm away from the trunk and out to the side.
At the thumb, it describes movement of the digit forward from the anatomical
position, away from the palm. This is because, in evolutionary terms, the thumb
of the primitive hand lies in the same plane as the fingers and abduction
carries it sideways away from the midline, just like the arm abducts at the
shoulder. In man, the thumb has rotated from its atavistic position, through 90°,
to allow human grasp.
Adduction:
Movement of a part towards the midline, e. g. adduction at the hip
joint moves the leg toward the midline and adduction of both legs would press
the knees together or cross the legs.
Allodynia: pain from stimuli that are not normally painful, or pain that occurs other than in the area stimulated
Algodystrophy: See Reflex Sympathetic Dystrophy
Allograft:
Graft of tissue from another individual of the same species, who is genetically
different from the recipient. Bone is generally transplanted without
revascularisation. Histocompatibility studies (tissue typing), essential in
organ transplantation, are not necessary in bone allografting.
Anaerobic: Those metabolic
processes which are not dependent on oxygen. Anaerobic organisms can therefore thrive in tissues which
are hypoxic or anoxic.
Anastomosis:
A junction between two vessels, or other tubular anatomical structures.
Anatomical
position: The reference position of the body – standing facing the
observer, with the palms of the hands facing forward.
Anatomical reduction; the exact adaptation of fracture fragments (hairline
adjustment) in preparation for surgical fixation. It will result in complete
restoration of the normal anatomy. While overall stability does not necessarily
depend on precise reduction, precise reduction more reliably results in
stability and increased strength of fixation. It is more important in articular
fractures than in diaphyseal fractures – see also Stability of fixation.
Angular stability: the property of an implant for fracture stabilisation, which is designed in such a way that the discreet parts of the implant, when assembled, are fixed in their angular relationship to each other. Usually applied to plates and screws, when the screw heads, once driven home in the plate hole, bind to the plate - this is achieved by an external thread on the screw head which engages with an internal thread in the plate hole. This principle was first described in 1935 by Rheinhold (France). See Locking Plate
Angulation: The orientation of one body (e.g. bone fragment) to
another in such a manner that the two parts meet at an angle other than a
straight line. The standard surgical convention is that the angulation is
characterized by describing the deviation of the distal part from its anatomical
position. For example, at a Colles' fracture, the distal radial fragment is
dorsally (or posteriorly) angulated, even though the apex of the deformity
points anteriorly: similarly a tibial fracture whose apex of angulation points
backwards, should be referred to as angulated anteriorly, as the distal part is
indeed angulated anteriorly from its anatomical position.
Ankylosis
Fusion of a joint by bone or a tight fibrous union,
occurring as a result of a disease process, e.g. following septic arthritis (pyarthrosis),
in ankylosing spondylitis, healed tuberculosis of bone etc.
Antalgic: Literally against pain. Used to describe an alteration of gait, where the stance phase one one side is abruptly shortened to avoid weight-bearing pain in that leg.
Anterior:
The front aspect of the body in
the anatomical position. If A is in front of B in the anatomical position, then
A is said to be anterior to B.
Antibiotic: Any drug, such as penicillin,
produced by certain fungi, bacteria, and other organisms, which can inhibit the
growth of (bacteriostatic), or destroy (bactericidal), micro-organisms. They are used
for the prevention, or treatment, of infections.
Antibody:
A substance produced by the host’s immune system, in
response to the detection of an antigen (q.v.). The antibody is
specifically elaborated to attack and destroy only the antigen which stimulated
its production – antigen specific.
Antigen: Component of a foreign biological substance (transplanted tissue,
invading virus, etc.), which stimulates the host’s immune system to attack
that foreign substance by
elaborating an antibody
(q.v.) that destroys the antigen and, in so doing, usually results in damage to
the “invader”
Arthritis:
Literally, an inflammatory condition of a diarthrodial (synovial)
joint. It may be septic or aseptic. The former may be blood-borne infection
(haematogenous), more common in children, or it may follow penetration of the
joint by wounding or surgery. Aseptic arthritides are usually of the rheumatoid
type (including Reiter’s syndrome, psoriatic arthropathy, etc.), or due to
degenerative change (see Osteoarthritis. Rheumatoid arthritis).
Arthrodesis: Fusion of a joint by bone, as a planned outcome of a surgical
procedure.
Articular fracture - partial: These fractures involve only part of the articular
surface, while the rest of that surface remains attached to the diaphysis.
There are several varieties:
·
pure
split: A fracture, resulting from a shearing force, in which the direction of
the split is usually longitudinal.
·
pure
depression: An articular fracture in which there is pure depression of the
articular surface without a split. The depression may be central or peripheral.
·
split-depression:
A combination of a split and a depression, in which the joint fragments are
usually separated.
·
multifragmentary
depression: A fracture in which part of the joint is depressed and the fragments
are completely separated.
Articular
Fracture - complete: The articular surface is disrupted and
completely separated from the diaphysis. The severity of these fractures depends
on whether their articular and metaphyseal components are simple or
multifragmentary.
Atrophic nonunion: if a fracture fails to heal because the biological responses leading to bony union are frustrated, usually due to adverse biological status of the fracture locus, the nonunion is categorised as atrophic, with absence of callus, rounding off of the bone ends and finally the formation of a false joint, or pseudarthrosis. See Nonunion.
Autograft:
Graft of tissue from one site to another within the same individual (homograft).
Avascular
necrosis: Bone which has been deprived of its blood supply dies. In the
absence of sepsis, this is called avascular necrosis (aseptic necrosis). The
dead bone retains its normal strength until the natural process of
revascularisation by “creeping
substitution” (see Blood
supply) starts to remove the dead bone, in preparation for the laying
down of new bone. Loaded areas may then collapse – segmental collapse. This
occurs in the femoral head and the talus more frequently than at other skeletal
sites.
Avulsion:
Pulling off
Bactericidal: Capable of killing bacteria.
Biocompatibility: The ability to exist in harmony with, and not to injure, associated biological tissues or processes.
Biological
(biologically respectful) internal fixation:
In any internal fixation there is always a skilful balance to be struck between
the degree of surgical stabilization produced and the biological insult caused
by the necessary surgical
intervention. The benefits of each will be judged by an experienced surgeon.
Biological fixation utilizes a surgical exposure technique which favours the
preservation of the blood supply, and thereby optimizes the healing potential,
of the bone and soft tissues, whilst providing sufficient stability for
multifragmentary fractures to heal in correct length and alignment. For the
protection of the implants from mechanical failure (fatigue or loosening), it
relies on a rapid biological healing reaction (early callus formation).
Biopsy: The surgical removal of a piece of tissue for histological
or microbiological examination, usually undertaken to establish a diagnosis.
Blood
supply to cortical bone (restoration of): Cortical bone which
has been completely deprived of its blood supply for any extended period of time
dies. It may become revascularised, either by ingrowth of blood vessels without
marked widening of the Haversian canals (Pfister et al. 1979), or by newly
formed Haversian canals, which result from the penetration of osteons.
Such osteonal remodelling is a process with a marked lag period and a slow speed
(0.1 mm/day according to Schenk 1987). When aseptic necrotic bone is
revascularised by resorption and replacement with newly formed, vascular bone
the term creeping substitution is often applied. See Vascularity
and Avascular Necrosis
Bone Graft: Bone removed from one skeletal site and placed at another. Bone
grafts are used to stimulate bone union and also to restore skeletal continuity
where there has been bone loss – see Allograft,
Autograft, Xenograft.
Broad
Spectrum: Refers to antibiotics
which are active against a wide spectrum of different organisms.
Butterfly
fragment: Where there is a fracture complex with a third fragment which does
not comprise a full cross section of the bone (i.e. after reduction there is
some contact between the two main fragments), the small wedge-shaped fragment,
which may be spiral, is occasionally referred to as a butterfly fragment – see
Wedge fracture
Buttress:.
A
buttress
is defined by the Oxford
English Dictionary as a structure of wood, stone, or brick, built against a wall
to strengthen, or support it. Derived from the Fr. bo(u)terez – a thrusting arch. The flying buttresses of cathedrals
are architectural examples.
Callus: Callus
formation is the response of living bone to any irritation – chemical (Küntscher
1970), infective, mechanical instability (Hutzschenreuter et al. 1969), etc.
Callus is a tissue complex formed at a site of bony repair. Fracture healing
tissue makes a gradual and progressive transition through a series of tissue
types – haematoma
ð granulation tissue
ð fibrous tissue (or fibro-cartilaginous tissue)
calcified tissue remodelling into woven bone, gaining in stiffness as
it does so.
In internal fixation with anatomical
reduction and absolute stability, where direct (callus-free) bone healing is
expected, the appearance of callus is a sign of unexpected mechanical
instability and should alert the surgeon to a failure of the original mechanical
objective (formerly referred to as “irritation” callus). Callus is welcome
as a repair tissue in all treatment methods where only relative fracture
stability has been the planned goal.
Cancellous bone: Is the spongy trabecular bone (spongiosa)found mostly at the
proximal and distal diaphyseal
bone ends in contrast with the dense cortical bone of the shafts. Cancellous
bone has a much larger surface area per unit volume and is, therefore, more
readily available to the blood supply, as well as to osteoclasts for resorption.
Its large surface/volume ratio also offers more surfaces for invading blood
vessels when attempting to revascularise dead cancellous bone, and this is an
advantage when cancellous bone is used for bone grafting.
Caudad: Literally "tailward". If A is nearer to the
"tail", or coccyx, than B, then A is caudad of B.
Caudal:
Pertaining
to the tail, or tail region, e.g. caudal epidural injection
Causalgia: see Complex Regional Pain Syndrome
Cephalad: Literally "headward". If A is nearer to the head
than B, then A is cephalad of B.
Chemotherapy:
Treatment of malignant lesions with drugs that impair,
or stop, their cellular proliferation.
Chondral: Pertaining to cartilage. Consisting of cartilage.
Chondrocytes:
The active cells of all cartilage, whether articular
cartilage, growth cartilage, fibrocartilage, etc. They produce the chondral
matrix, both its collagen and the mucopolysaccharides of the ground substance.
Cis–cortex: – see Near cortex
Comminution; Comminuted: - Refers to a fracture with multiple fragments, that is more than 2 main fragments. Syn. multifragmentary
Compartment syndrome: - see Muscle Compartment
Complex fracture: Fracture
in which, after reduction, there is
no contact between the main
fragments.
Complex Regional Pain Syndrome:
Complex Regional Pain Syndrome (CRPS) is a disorder of
unknown pathophysiology, which can affect either the upper or lower limbs. This
disabling syndrome is not related to a single nerve territory and is
disproportionate to the initiating event. The most prominent features include
burning pain and functional impairment of the affected limb. Only 1 in 5
patients returns to a normal level of function.
Categorised as types I and II; the clinical features of CRPS type I comprise
regional pain, sensory change, allodynia,
abnormalities of temperature regulation, abnormal sudomotor activity, oedema,
and skin discolouration, accompanying noxious events. CRPS type II includes the
aforementioned features, but in association with a peripheral nerve lesion. The
incidence of CRPS is approximately 1 in 2000 traumatic events. Previously
CRPS Type I was known as Reflex Sympathetic Dystrophy and CRPS type II
was known as Causalgia.
In order to establish a diagnosis of CRPS, 3 of
the following 4 criteria must be present:
- An initiating, noxious event, or cause of immobilisation.
- Continuing pain, allodynia (pain from stimuli that are not normally
painful, or pain that occurs other than in the area stimulated), or excess
pain, disproportionate to the irritating event.
- Oedema, altered skin blood flow, or abnormal sweating in the region of the
pain at some time.
- The diagnosis is excluded by absence of a condition to account for the degree
of pain and dysfunction.
Compound fracture: The British school has long referred to fractures
with an overlying, communicating wound of the integument as “compound”
fractures, the opposite being “simple” fractures. No fracture should be
regarded as simple, and the use of the archaic word “compound” does not
convey the important clinical distinction. Now largely superseded by Open fracture.
Compression Screw: – see Lag
screw.
Compression: The act of pressing together.
It can result in deformation (as in shortening a spring) and improvement in, or
creation of, stability. Compression is used (1) to provide absolute stability of
fracture fixation, where indicated, and (2) to protect the fixation implants and
to improve their efficiency by reducing the dynamic
stresses on them them. Unloading is achieved through restoration of the
load‑bearing capacity of the bone. Any fixation taking advantage of the
load‑bearing capacity of fracture fragments can withstand load without
mechanical failure, or temporary micromotion, at the fracture. This is the main
reason for using careful reduction and the application of compression.
If the implant (screw, plate) bridging the fracture is applied under tension,
then the fracture locus undergoes an equivalent amount of compression. The
compression is used to help stabilize the fracture. Compression does not confer
any "magic biological effect" on fracture healing – it merely
provides the degree of absolute stability deemed necessary by the
decision-making surgeon.
Contact healing: Occurs
between two fragment ends of a fractured bone, at places which are maintained in
motionless contact. The fracture is then repaired by direct osteonal
remodelling. Contact healing may also be observed where the gap is only a few
micrometers wide.
Continuous Passive Motion: see C.P.M.
Coronal:
This is a vertical plane of the
body passing from side to side, so that a coronal bisection of the body would
cut it into a front half and a back half. It is so called because at a
coronation, the crown (corona in
Latin) is held with a hand on either side as it is lowered onto the royal head;
the line joining these hands is in the "coronal" plane.
Cortex:
– see Cortical bone
Cortical
bone: The dense bone forming the tubular element of the shaft, or diaphysis
(middle part) of a long bone. The term cortex is also applied to the dense, thin
shell covering the cancellous bone of the metaphysis. The two terms are
generally used interchangeably.
Corticotomy: A special osteotomy
where the cortex is surgically divided, but the medullary contents and the
periosteum are not.
C.P.M. – Continuous Passive
Motion: The use of powered
apparatus to move a joint through a controlled range of motion has been shown to
enhance articular cartilage healing after joint injury and to promoted soft
tissue recovery after surgery. Salter, Mitchell & Sheperd, and others, have
demonstrated that the use of passive motion machines for continuous periods is
necessary for cartilage repair. The indiscriminate use of CPM machines for
prolonged periods for other indications can lead to muscle wasting and should be
combined with other techniques of physical therapy.
Creeping substitution: – see Blood supply , Avascular necrosis
Cytoplasm:
The non-nuclear substance of a cell.
Debricolage: A French term
signifying the process of mechanical failure of an internal fixation prior to
the onset of solid bone healing.
Débridement: Literally the “unbridling” of a wound. Strictly
speaking, it refers to the extension of a wound and the opening up of the planes
of the injured tissue, usually in the context of open fractures, as described by Amboise Paré in the 16th century. It has come to be used loosely to
encompass the whole process of opening up of a wound, or pathological area (e.g.
bone infection), together with the surgical excision of all avascular,
contaminated, infected, or other undesirable tissue.
Deformity: Any abnormality of the form of a body part.
Degenerative joint disease (DJD) - see Osteoarthritis
Delayed union:
The failure of a fracture to consolidate within the
normally expected time, which varies according to age, fracture type and
location. Delayed union, like union
is a surgical judgment
Diaphysis: The cylindrical, or tubular, part between the ends of a long bone, often referred to as the shaft.
Direct
healing: A type of fracture
healing observed with absolutely stable (rigid) internal fixation.
It is characterized by:
1. Absence of callus formation specific to the fracture site.
2. Absence of bone surface resorption at the fracture site.
3. Direct bone formation, without any intermediate repair tissue.
Direct fracture healing was formerly called "primary" healing, a term
avoided today in order not to imply any suggestion of grading of the quality of
fracture healing. Two types of direct healing are distinguished, namely contact
healing and gap
healing.
Distal: Away from the centre of the body; more peripheral. For
example, the hand is distal to the elbow, the phalanges are distal to the
metacarpals. In certain instances, it means nearer the end than the beginning;
for example, in the digestive system the stomach is distal to the oesophagus,
or, in the urinary tract, the bladder is distal to the ureter.
Dorsal: Pertaining to the back ‑ or dorsum ‑ of the
body in the anatomical position. An exception is the foot; the top of the foot,
even though it faces forward in the anatomical position, is called the dorsum.
Ductility: The ability of a material to develop significant, permanent deformation before it breaks. See plastic deformation.
Dynamisation: The
mechanical load transferred across a fracture locus can be increased, at a
certain healing stage, in order to enhance bone formation, or to promote
"maturation" of the healing tissues. An example would be the reduction
in stiffness of an external fixation, either by loosening some clamps, reducing
the number of pins, or moving the tubular construct further from the bone. Early
dynamisation, i.e. before solid bridging of the bone, can result in stimulation
of callus formation. The value of later dynamisation is debatable.
Elastic
deformation: -
see Plastic deformation
Endosteal:
The adjective derived from endosteum, which means the interior surface of a bone
– i.e. the wall of the medullary cavity.
Energy
Transfer: When tissues are
traumatised, the damage is due to energy that is transferred to those tissues.
This is most commonly due to the transfer of kinetic
energy from a moving object (car, missile, falling object, etc.). The
greater the amount of energy transferred to the tissue, the more extensive the
damage.
Epiphysis:
The end of a long bone that bears the articular component (joint).
The epiphysis develops embryologically from the cartilaginous element between
the joint surface and the growth plate – see Metaphysis.
Extension: The movement of an articulation
that causes the relationship between part above the joint and the part below the
joint to becomes straighter.
Extensor: Adjective from the noun "extension". The muscles
which cause extension of a part are its extensor muscles; the surface of a part
where those muscles are found is sometimes called the extensor surface.
Extra-articular
fracture: Does not involve the
articular surface, but it may be intracapsular (as in fracture of the femoral
neck)..
Far cortex
(trans-cortex):
The cortex more distant from the operator. In plating and tension band
wiring, a bony defect has more important consequences in the far cortex than in
the near cortex. This difference is due to the inability of a defective far
cortex to resist compressive forces.
Fascio–cutaneous:
A term describing tissue flaps that include, as a
single layer, the skin, the subcutaneous
tissues and the associated deep fascia.
Fasciotomy: The surgical division the investing fascial wall of an
osseo-fascial muscle compartment, usually to release pathologically high
intra-compartmental pressure – see Muscle
compartment syndrome.
Fibrocartilage:
Tissue consisting of elements of cartilage and of fibrous tissue. This may
be a normal anatomical structure, such as certain intra-articular structures
(menisci, triangular fibrocartilage at the wrist, or temporo-mandibular joint,
or the symphysis pubis), or may constitute the repair tissue after lesions of
the articular (hyaline)cartilage.
Fixation, flexible: Traditionally, internal fixation according to AO ASIF method meant absolutely stable (rigid) fixation, using close adaptation and compression of the bony fragments. Latterly, a less stable fixation (flexible fixation using splinting plates, intramedullary nails, or fixators) has been observed to yield very good results under conditions in which the fragments are well vascularized. Given best preservation of the viability of the fragments, flexible fixation induces abundant and rapid callus formation. Recall that the combination of instability and compromise of the biology of the fracture locus is deleterious. See Biological internal fixation
Flexion: The movement of an articulation
that causes the relationship between part above the joint and the part below the
joint to become more angulated.
Flexor: Adjective from the noun "flexion". The muscles
which cause flexion of a part are flexor muscles; the surface of a part where
those rnuscles are found is sometimes called the flexor surface.
Floating
Knee: Isolation of the knee joint from the remainder of the skeleton by
fractures of the femur and the tibia in the same limb.
Fracture:
A loss of continuity (breakage), usually sudden, of any
structure resulting when internal stresses produced by load exceed the limits of
its strength. The complexity and displacement of the fracture depend largely on
the energy build-up in the structure prior to fracture. The shape of the
fracture planes (transverse fracture, spiral fracture, avulsion, impaction etc.)
is related to the nature of the load‑ compressive, bending, torsional,
shear, or any combination of these.
Fracture
disease: A condition characterized
by inappropriate pain, soft tissue swelling, patchy bone loss and joint
stiffness (Lucas-Championnière 1907).
Fracture disease can best be avoided by that system of fracture management most
likely to produce skeletal integrity, whilst permitting early active motion of
the part (early functional rehabilitation) (Allgöwer
1978).
Fracture locus (injury zone). Locus derives from the Latin word for
“place”. It is used in yhis context to describe the biological unit
comprising the fracture fragments and the immediately associated soft tissues,
all of which function together to produce healing of the injury.
Fracture, articular:
involves the articular surface. They are subdivided into partial
and complete.
Fracture,
extra-articular: These do not involve the
articular surface, although they may be intra‑capsular. They include
apophyseal and metaphyseal fractures.
Fracture, impacted: A stable, and usually simple, fracture of the
metaphysis or epiphysis in which the fragments are driven one into the other,
resulting often in inherent fracture stability.
Fracture, multifragmentary: A term used to characterize any fracture with one or
more completely separated intermediate fragment(s). In the diaphyseal and
metaphyseal segments, it includes the wedge and the complex fractures. The terms
wedge and complex are used only for diaphyseal or metaphyseal fractures.
- wedge: A
fracture with one or more intermediate fragment(s) in which, after reduction,
there is some contact between the main fragments. The spiral, or bending,
wedge may be intact, or fragmented.
- complex: A
fracture with one or more intermediate fragment(s) in which, after reduction,
there is no contact between the main proximal and distal fragments. The complex
fractures are spiral, segmental or irregular. The term comminuted is imprecise
and should not be used.
Fracture, simple: A term used to characterize a single circumferential
disruption of a diaphysis or metaphysis or a single disruption of an articular
surface. Simple fractures of the diaphysis or metaphysis are spiral, oblique or
transverse.
Frontal: Pertaining to the front of the body in the anatomical position. That part of the skull forming the forehead is the frontal bone. The frontal plane of the body, parallel to the front, is the same as the coronal plane
Fusion: see Arthrodesis
Galeazzi injury: A
fracture of the radial shaft associated with a dislocation of the inferior
radio-ulnar joint. Its first description is attributed to Galeazzi (1934).
Sometimes referred to as the “reversed Monteggia”
Gap
healing: The healing process taking place between two fragment ends kept in
stable relative position with a small gap between them. Gap healing progresses
in two phases: (1) the filling of the gap with lamellar bone orientated parallel
to the plane of the fracture gap, (2) the subsequent osteonal
remodelling of the newly formed lamellar bone.
Gliding
hole: When a fully threaded screw is used as a lag screw, the cortex under the screw head (near
cortex, or cis-cortex) should not engage the screw threads. This can be
accomplished by over-drilling the near cortex hole to at least the size of the
outer diameter of the screw thread.
Gliding splint: A splint
(such as an unlocked intramedullary nail) which allows for axial shortening.
Such a splint provides the possibility for the re-establishment of bony
coaptation under conditions of fragment end shortening due to bone surface
resorption.
Goal of fracture treatment: According
to Müller et al. (1963), the goal of fracture treatment is to restore optimal
function of the limb in respect to mobility and load-bearing capacity. The goal
is furthermore to prevent early complications, such as reflex sympathetic dystrophy, fracture
disease, or Sudeck's atrophy and, in the case of polytrauma, multiple
system organ failure, as well as late sequelae, such as post-traumatic
arthrosis.
Haematogenous: Blood-borne.
Haversian
System
The cortical bone is
composed of a system of small channels (osteons) about 0.1 mm in diameter. These
channels contain the blood vessels and are remodelled after a disturbance of the
blood supply to bone. There is a natural turnover of the Haversian systems by
continuous osteonal remodelling; this process is part of the dynamic and metabolic
nature of bone. It is also involved in the adaptation of bone to an altered
mechanical environment
Hawkin's test. A test for subacromial impingement at the shoulder. With the arm in the throwing position and flexed forward about 30 degrees, passively internally rotate the humerus. Pain suggests impingement of the supraspinatus tendon against the coraco-acromial ligament. Crepitus can also often be detected at the subacromial bursa. For shoulder examination, see http://www.usask.ca/cme/articles/fmse/index.php
Healing: Restoration of original integrity. The healing process after a bone fracture lasts many years, until internal fracture remodelling subsides. For practical purposes, however, healing is considered to be complete when the bone has regained its normal stiffness and strength.
Heterograft – see Allograft
and Xenograft.
Homograft – see Allograft and Autograft
Horizontal: Parallel with the horizon: unrelated to the anatomical position.
Hypertrophic nonunion: if a fracture fails to heal, despite good fracture locus biology, due to a mechanical environment which is so unstable as to frustrate the tissue responses, the non-union is categorised as hypertrophic. Abundant new bone formation will often produce the so-called “elephant’s foot” appearance on x-ray. See Nonunion
Hypovolaemia: A state where the circulating blood volume is reduced.
This can occur due to haemorrhage, or other loss of fluid, such as dehydration.
It can lead to shock.
Hypoxia: A state where the oxygen level in the arterial blood, or in other
tissue, is pathologically reduced.
Impacted fracture: See Fracture impacted
Indirect healing: Bone
healing as observed in fractures treated either with relative stability, or left
untreated. Callus formation is
predominant, the fracture fragment ends are resorbed, and bone formation results
from a process of transformation of fibrous and/or cartilaginous tissue into
bone – see Callus.
Inferior:
Literally below or lesser than.
In the anatomical position, if A is lower than B, A is inferior to B. The
opposite is superior.
Inoculation
The instillation, either accidental or deliberate, of micro‑organisms into
body tissues, or into a culture medium.
Interfragmentary compression: Static compression applied to a fracture plane
imparts a high degree of stability to the fragments and thus reduces micromotion
and strain. Bone surface resorption does not then occur. There is no
demonstrable proof that interfragmentary compression, per se, has any effect
upon internal remodeling of the cortical bone (Matter et al. 1974).
Intramedullary nail – locked or unlocked: An intramedullary nail provides some degree of stability, mainly as
a result of its (flexural) stiffness. An unlocked nail will allow the fragments
to slide together along the nail; the fracture must therefore be provided with a
solid support against shortening – see Gliding splint. For the treatment of
multifragmentary fractures, where there is axial instability (the fear of
collapse into a shortened position), the nail can be interlocked above and below
the fracture locus to prevent this shortening and also to reduce rotational
displacement. This is achieved by locking bolts traversing a locking hole
prepared in the nail and passing through the cortex on either side of the nail.
If the locking hole is round and matches the size of the locking bolt, then
static locking has been achieved. If the locking hole is elongated in the
nail’s long axis, the possibility of a limited excursion of axial movement is
achieved, whilst preserving the rotational control– so-called dynamic locking.
Ischaemia Absence of
blood flow.
Kinetic
energy – see Energy transfer. The energy stored by a
body by virtue of the fact that it is in motion. As energy cannot be destroyed,
when a moving object is slowed or stopped, its kinetic energy is converted into
other energy. If a moving object strikes a slower, or stationary object, it
imparts some of its kinetic energy to the body that it strikes. This may
accelerate the other body (or parts of it), causing damage, or produce other
energy transfer effects such as heat production – the sparks seen when a metal
bullet hits a rock, for example. Kinetic energy is calculated according to the
formula E=½ mv2, where m is the mass of the moving object and v its
velocity.
Kyphosis: Spinal deformity in which there is angulation forwards in the sagittal plane. Sharp angulation may result from abnormality of only one vertebral body, and is called an angular kyphosis, or gibbus (as after a severe wedge fracture, or tuberculous collapse of a vertebral body). A more gentle kyphosis is due to deformity involving several adjacent vertebrae, as in osteoporosis affecting the thoracic spine (“Dowager’s hump”)
Lag screw technique: Produces interfragmentary compression by driving the
bone fragment beneath a screw head against another fragment in which the screw
threads obtain purchase The compression produced by a screw so inserted acts
directly within the fracture surface and is therefore very efficient. A screw
designed specifically for this purpose, being only partially threaded is a lag
screw, or shaft screw. A full threaded screw used with an over-sized hole in the
near cortex to prevent thread purchase in the near fragment (a gliding
hole) is strictly speaking not a lag screw but a threaded screw used
with a lag technique; it is, nevertheless, often loosely termed a lag screw.
Interfragmentary compression will be reduced by engagement of the screw threads
with the walls of the gliding hole. Anchorage in the near fragment can be
avoided by the use of a shaft screw. This technique is also required to maintain
efficient compression when a screw is inserted through the plate and across a
fracture plane in an inclined position.
Lateral:
Literally, of, or toward, the
side. The side of the body in the anatomical position is the lateral aspect or
surface. If A is nearer the side of the body than B (further from the midline),
then A is lateral to B. The opposite is medial.
Locking plate: A plate with threaded screw holes that allow mechanical coupling to a locking head screw. The AO Less Invasive Stabilisation System (LISS) will accept only this type of screw,. whilst AO Locking Compression Plates (LCP) have a combination hole that will accept normal screw heads or threaded screw heads. See Angular Stability
Locking head screw: Screws with external threads cut onto the head, which provide a mechanical couple to an internal thread in the screw hole of a plate, thus creating a fixed angle device.
Lymphoedema:
Accumulation of oedema fluid in the tissues as a result
of poor drainage of the lymph, usually due to the incompetence, or obstruction,
of the lymphatic vessels.
Malunion: Consolidation of
a fracture in a position of deformity.
Matrix: Literally, a place
or medium in which something is bred, produced, or developed. In cartilage, it is
the substance between the chondrocytes. It comprises a network of collagen
fibres interspersed with a "jelly" of waterlogged mucopolysaccharide
macromolecules (complex organic chemicals in large molecular chains).
Medial: Literally, of or toward the middle, or median. The inner
side of a part with the body in the anatomical position is the medial aspect or
surface. If A is nearer the middle, or centre–line, than B, then A is medial
to B. The opposite is lateral.
Metaphysis:
The segment of a long bone located between the articular end part (epiphysis) and the
shaft (diaphysis). It consists mostly of cancellous bone, within a thin cortical
shell.
Methylmethacrylate: A chemical substance, the monomer of which can be induced to
polymerise, producing a hard plastic. It can be a form of bone cement (polymethylmethacrylate
– or PMMA), but in a different polymerised form it produces Perspex.
Microvascular:
Pertaining to microscopic blood vessels.
Microvascular tissue transfer is related to the technical need for an
operating microscope to perform the anastomoses (see Anastomosis).
Midline: The centre line of the body in the anatomical position.
Minimally invasive plate osteosynthesis (MIPO): reduction and plate fixation without direct surgical exposure of the fracture site, using small skin incisions and sub-muscular insertion of the plate.
Monteggia
injury A displaced ulnar fracture associated with a dislocation of the
radial head from its articulation with the capitellum of the humerus, at the
elbow. First described in the 19th
century by the Italian physician Giovanni Battista Monteggia.
Multifragmentary
fracture: A term usually reserved for fractures which have one or more
dissociated intermediate fragments.
Muscle Compartment An
anatomical space, bounded on all sides by bone and/or deep fascial envelope,
which contains one or more muscle bellies. The relative inelasticity of its
walls means that if the muscle tissue swells, the pressure in the
osseo–fascial envelope can increase to levels which cut off the flow of blood
to the muscle tissue, resulting in its severe compromise or death – so-called Muscle
Compartment Syndrome.
Muscle Compartment Syndrome.
Diagnosis
In “Fractures with Soft Tissue Injuries”, edited by Tscherne and Gotzen
(1984), there is an excellent chapter on compartment syndrome. Under the heading
of “Diagnosis of Compartment Syndromes, Clinical Examination” (p.83) it
states:
“In the conscious patient, the earliest and most important symptom is of
a burning, boring pain of acute onset which may be spasmodic in nature and tends
to increase with time. Sensory aberrations are also reported in the form of
paraesthesiae, hypoaesthesiae, and rapid sensory losses. In co-operative
patients, disturbances of muscular function are demonstrable as motor weakness
after two to four hours of ischemia. On palpation, the affected muscles are
tender and have a firm to stony-hard consistency. Peripheral arterial pulses and
capillary perfusion are intact in the early stage, provided there is not
concomitant arterial injury”.
They then describe, as do most modern texts, techniques for direct measurement
of compartment pressure in cases where there may be some doubt as to the
diagnosis.
In “Skeletal Trauma”, edited by Browner, Jupiter, Levine and Trafton (1992)
Rorabeck states: “Assuming the patient is conscious and alert, the most
important symptom of an impending compartment syndrome is pain disproportionate
to what might be expected given the problem the patient is being treated for.
Frequently the patient presents with a relatively pain-free interval, perhaps a
few hours following reduction of the fracture, and then develops pain out of
proportion to the problem. The degree of pain can usually be assessed by the
requirements for analgesia, or even stronger analgesia. The pain felt by the
patient is unrelenting and seems to be unrelated to the position of the
extremity or to immobilization. The patient might also complain of feelings of
numbness or tingling in the affected extremity. These symptoms are poorly
localized and are not to be relied on. Clinical signs of an impending acute
compartment syndrome, irrespective of the underlying cause, include pain on
palpation of the swollen compartment, reproduction of symptoms with passive
muscle stretch, sensory deficit in the territory of the nerve traversing the
compartment and muscle weakness. The earliest sign of an acute compartment
syndrome is a tensely swollen compartment, which on palpation reproduces the
patient’s pain”.
Treatment by fasciotomy:
It is not always possible at fasciotomy to determine exactly which muscle has
died and which has not, although this is usually evident when the muscles are
reviewed 24 to 48 hours later.
According to Tscherne and Gotzen (1984): “Decompressive fasciotomy is an
emergency procedure, and facilities for this operation should be available at
all times. Promptness has a critical bearing on the prognosis. According to
McQuillen and Nolan (1968) and Matsen and Clawson (1975), disturbances of
muscular microcirculation that persist longer than 12 hours produce significant
motor and sensory deficits as well as myogenic contractures. Keays (1981) states
that, based on his experience, good results are obtained only if decompression
is performed within 6 hours of the onset of compartment syndrome. He further
states that permanent defects may be expected after 8 hours, and that amputation
will very likely be needed if surgery is delayed beyond 12 hours. Of his ten
patients treated by fibulectomy, only four had a good end result.
Most findings on the temporal relationship between circulatory impairment and
reparative tissue tolerance are based on experimental total ischemia. Nerves
showed functional deficits after only 30 minutes ischemia. Irreversible pareses
developed after 12 - 24 hours of complete ischemia (Holmes et al. 1944, Malam
1963). Compensatable partial myogenic disturbances were observed after only 2 -
4 hours ischemia, and an irreversible loss of function after 4 - 12 hours
(Harman 1948, Whitesides 1971). These findings are consistent with our own
clinical observation that permanent functional deficits arise within 4 - 6 hours
of the onset of a frank, untreated compartment syndrome”.
This publication also quotes work of Oestern and Echtermeyer (1982), who
reviewed 123 compartment syndromes, including late referrals. They reported:
“Late sequelae developed in 36 patients, 35 of whom had a compartment
syndrome of the lower leg. Twenty-nine displayed weak dorsiflexion of the foot,
four had a claw-toe deformity and nine complained of sensory losses.
Analysing the sequelae that occurred after fasciotomy, we find that late changes
developed in only three patients who underwent a fasciotomy within the first six
hours after their injury. By contrast, late changes occurred in twenty-two
patients in whom decompression was delayed beyond twenty-four hours. Ten
patients eventually had to undergo an amputation; in none of these cases had a
decompressive fasciotomy been performed within the first six hours (1 within the
first 12 hours, 2 between 12 and 24 hours and 7 more than 24 hours
post-injury)”.
The results of Oestern and Echtermeyer (1982) suggest, decompression of the
muscle compartments within six hours of the clinical onset of the compartment
syndrome, would be likely to result in no late sequelae.
The dead and disintegrating muscle cells can release the muscle pigment
myoglobin into the surrounding tissue fluid and this can then reach the blood
circulation, especially after release of the raised intra-compartmental
pressure. This may cause the presence of myoglobin in the urine (myoglobinuria),
this being an indication of extensive muscle death. Frank myoglobinuria may be
expected to start within a few hours of the restoration of the muscle
circulation by fasciotomy.
Neutralization: An implant (plate, external fixator, or nail) which functions by virtue of its stiffness. The stiffness is said to "neutralize" the effect of the functional load. The implant carries a major part of the functional load and thus diverts loads away from the fracture locus and may serve to protect a more vulnerable element of a fixation complex. An example is where a spiral fracture has been reduced and fixed with interfragmentary screws, and then a plate is applied to protect the primary screw fixation from functional loads which could disrupt it. The use of such a protection, or “neutralization”, plate will allow earlier function aftercare than had the screw fixation been left unsupported. It does not actually "neutralize", but does minimize, the effect of the forces (see Protection).
Non-steroidal inflammatory drugs - see NSAIDS
Nonunion (or non-union): (see also Union, Pseudarthrosis,
Delayed Union)
Nonunion is failure of bone healing. A fracture is judged to be ununited if the
signs of nonunion are present when a sufficient time has elapsed since injury,
during which the particular fracture would normally be expected to have healed
by bony union. That period will vary according to age, fracture location and
patho-anatomy.
The signs of nonunion include persisting pain and/or tenderness at the
fracture sight, pain and/or mobility on stressing the fracture site, and
inability progressively to resume function. Slight warmth may be detected if the
fracture site is subcutaneous. Radiographs will be likely to show failure of
re-establishment of bony continuity.
When a fracture has been fixed internally, loosening and/or breakage of the
implant may indicate the instability of a nonunion.
If a nonunion has resulted from a mechanical environment at the fracture locus
that is not conducive to bone healing, despite good fracture biology and
osteogenic response, a hypertrophic
nonunion (“elephant’s foot”) occurs – the solution
to this is a mechanical one.
If a nonunion has resulted from impaired biological response at the fracture
locus, an atrophic nonunion occurs – the
solution to this is biological enhancement, usually with mechanical support.
NSAIDS: non-steroidal inflammatory drugs. See http://www.healthline.com/galecontent/nonsteroidal-anti-inflammatory-drugs-1
Opposition (anatomical): The action of opposing one part to another; if the pulp of
the thumb is placed in contact with the pulp of a finger, the movement, or
action, of the thumb is that of opposition.
ORIF: A widely used abbreviation for open reduction and internal fixation (osteosynthesis).
Osteoarthritis :
This is a degenerative condition
which affects diarthrodial (synovial) joints and is characterized by loss of
articular cartilage, reactive subchondral bone sclerosis (sometimes with
subchondral cysts) and the formation of peripheral bony outgrowths –
osteophytes. The primary lesion is degeneration of the articular cartilage as a
result of infection, trauma, overuse, congenital skeletal anomaly, or as part of
the aging process
Osteoarthritis may be primary, where there is no identifiable prior insult to
the articular cartilage (usually associated with the aging process), or
secondary, in which case the degeneration of the articular cartilage is
initiated by congenital joint abnormality, injury, infection, deformity of the
limb, joint instability, identifiable overuse, inflammatory joint disease, such
as "burnt out" rheumatoid arthritis, etc.
Osteoarthrosis - see Osteoarthritis
Osteoblast:
A cell that forms new bone
Osteoblastic:
Producing bone.
Osteoclast:
Cell that destroys bone. Osteoclasts rest in the
Howship lacunae (small spaces within the bone surface). They are typically found
at the tips of the remodelling osteons,
but also in all sites where bone is being removed by physiological processes.
Osteolytic:
Resorbing, destroying or removing bone.
Osteomyelitis: An acute or chronic inflammatory condition
affecting bone and its medullary cavity, usually the result of bacterial
(occasionally viral) infection of bone. This may be a blood-borne infection
(haematogenous osteomyelitis) – usually in children or in the immunologically
compromised - or follow an open fracture (post-traumatic osteomyelitis).
The acute form, if diagnosed early and treated vigorously, can heal with no
residual effects. If the diagnosis is delayed then the infection and the
consequent interference with the local bone blood supply, can result in dead
bone (which may separate to form one or more sequestra – see
Sequestrum)
that remain infected in the long term because the defence mechanisms have no
vascular access to it. The treatment of chronic osteomyelitis is surgical and
includes wide excision of all dead and infected tissue, the identification of
the responsible organism, and the delivery, both locally and systemically, of
appropriate anti-bacterial agents.
Osteon (osteone)(cutter cone): This is a normal vascular structure concerned with bone remodelling, either as part of physiological bone turnover, or as part of the healing process after fracture. Anosteon comprises a vascular bud, at the tip of which is a cluster of osteoclasts. Behind the osteoclasts, the vessel is cuffed by osteoblasts. As the osteoclasts removed bone, they advance through the bone and the following cuff of osteoblastslays down concentric cylinders of osteoid, that matures to form the rings of bone seen in the walls of the Haversian systems of bone. The osten effectively drills a ne channel through existiung bone, then lines this channel with cylinders of new bone.
Osteopaenia (osteopenia): An abnormal reduction in bone mass. This may be
generalized, as in some bone diseases, or localized, as a response to
inflammation, infection, disuse, etc. See Osteoporosis
Osteoporosis:
A reduction in bone mass. It is a natural aging process
but may be pathological. It can result in pathological fracture (most fractures
of the femoral neck in the elderly are due to osteoporosis plus minimal trauma).
See Osteopaenia and
Pathological fracture.
Osteosynthesis:
A term coined by Albin Lambotte (1907) to describe the “synthesis” (derived
from the Greek suntithenai for putting together, or fusing) of a
fractured bone by a surgical intervention using implanted material. It differs
from “internal fixation” in that it also includes external fixation
Osteotomy: Controlled surgical division of a bone.
Overbending (of plate):
See Prebending.
Palmar:
Pertaining
to the palm of the hand, e. g. the palmar fascia, the palmar aspect of the
fingers.
Pathological
fracture: A fracture through bone which is abnormal as a result of a
pathological process. It may be the result of the application of a force less
than that which would be required to produce a fracture in a corresponding
normal bone.
Periosteal:
Adjective derived from periosteum.
Periosteum
is the inelastic membrane bounding the exterior surface of a bone. The
periosteum plays an active part in the blood supply to cortical bone, in
fracture repair and in bone remodeling. It is continuous with the perichondrium
– the membrane that bounds the periphery of the physis.
Pilon: The distal end of the tibia – from the French for a stump, or a pestle. Fractures of the distal tibial metaphysic caused by axial load failure are called “pilon fractures”
Pilot
hole: If a fully threaded screw is to function as a lag screw, the screw is
anchored near its tip, within a threaded hole in the far bone fragment. The
original drill hole which is made prior to tapping of the thread in the bone is
called the pilot hole. Within the bone fragment near the head of the screw, the
thread should not obtain purchase but should glide (gliding
hole). A pilot hole is also prepared when inserting a Schanz screw, or a
Steinmann pin.
Pin loosening:
The pins of external fixator frames serve to stabilize
the fragments of a fracture by linking the bone to the frame. Stability depends,
among other things, upon the contact between pin and bone (pin-bone interface).
Pin loosening occurs when bone surface resorption at the pin-bone interface
takes place due to excessive cyclical loading of the bone. Stability is thereby
reduced. However, pin loosening is less important in respect of loss of
stability than in respect of its deleterious effect in promoting pin track
infection.
Plafond (Fr.): Literally “ceiling”: used to denote the horizontal portion of tge distal tibial articular surface. See Pilon
Plantar: Pertaining to the sole of the foot, i.e., the surface of
the foot which is "planted" on the ground. Examples are the plantar
fascia, and the plantar surfaces of the toes. Plantar flexion is a movement at
the ankle which moves the foot downward, or in a plantar direction.
Plastic Deformation:
If an object is deformed within those limits which
allow it to regain its original form, once the deforming force is removed, it is
said to have undergone elastic deformation.
If the force is increased above the upper level for elastic deformation,
permanent deformity (known in engineering terms as “set”) is produced –
this is plastic deformation. When the deforming force is removed, the object
cannot return to its original form.
Plastic deformation, without fracture, can occur in the shape of a young,
growing bone following the application of a deforming force. The alteration in
shape does not "rebound" to the original as the bone has been stressed
beyond its elastic limit, but not to the point of breaking.
Polytrauma: Multiple injuries to one or more body systems. An Injury Severity
Score (ISS) of more than 16 is usually taken to indicate polytrauma.
Posterior: The back of the body in the anatomical position is the
posterior surface. If A is nearer to the back of the body in the anatomical
position than B, then A is posterior to B. Equivalent to dorsal, except in the
foot, where the dorsum is anterior in the anatomical position – see Dorsal
Prebending
of plate: Exactly contoured plates,
when loaded using either the external compression device or the DCP principle,
produce asymmetrical compression, i.e. the near cortex is more compressed than
the far cortex. Indeed, the latter may not be compressed at all and can be
distracted in certain cases. To achieve stabilization against both torque and
bending, compression at the far cortex is even more important than that of the
near cortex. To provide uniform compression across the whole width of the bone,
including the far cortex, the plate is applied after contouring with an
additional bend of the plate segment bridging the fracture. The bend is such
that the midsection of the plate is slightly elevated from the surface of the
reduced fracture, prior to fixation to the bone and the application of
compression. Prebending is an important tool to increase stability in small
and/or osteoporotic bones – see osteopaenia.
Precise reduction – see Anatomical reduction
Preload: The application of interfragmentary compression keeps the fragments
together until a tensile force is applied, exceeding the compression (preload).
Pronation: The movement of rotating the
forearm so that the palm of the hand faces backward from the anatomical
position. Pronation is also sometimes used to describe a movement of the foot
into inclination away from the midline, otherwise called eversion; so that a
pronated foot would bear more weight on its medial border than onits lateral
border
Prophylactic:
Preventive.
Protection: While the
term "neutralization" has often been used in plate and screw fixation,
the term "protection" should replace it. In reality nothing is
neutralized. In plate fixation the plate reduces the load placed upon the
interfragmentary screw fixation. It therefore protects the screw fixation from
overload – see Neutralization.
Proximal: Nearer to the centre of the body
in the anatomical position. The opposite of distal. Thus, the elbow is proximal
to the wrist. In certain instances, it means nearer the beginning than the end;
for example, in the digestive system the stomach is proximal to the ileum, or in
the urinary tract the kidney is proximal to the bladder.
Pseudarthrosis:
(see also
Delayed Union,
Nonunion,
Union) literally means “false joint”. When a nonunion is mobile and allowed
to persist for long periods, the ununited bone ends become sclerotic and the
intervening soft tissues differentiate to form a crude sort of synovial
articulation.
The term is often loosely and incorrectly used to describe all nonunions.
Occasionally, a pseudarthrosis (in the sense of a false articulation) may be
deliberately created surgically, as for example, in excision arthroplasty of the
hip (Girdlestone, Judet, Robert Jones), or excision of a segment of the distal
ulnar shaft, in combination with fusion of the inferior radio-ulnar joint
(Kapandji).
Excision of the radial head is another example of surgical pseudarthrosis.
Pure depression: An
articular fracture in which there is depression alone of the articular surface
without split – see Impacted
fracture and Pure split.
Pure split: An articular fracture in which there is a
longitudinal metaphyseal and articular split, without any additional
osteochondral lesion.
Radial preload To prevent external fixator pin loosening, the contact zone (interface) between the implant and bone can be preloaded, i.e. a static compressive force is applied. Hitherto, preloading was achieved by applying a permanent bending moment to the pins, within their elastic range. Currently, the pins are designed with a thread and shank that automatically generate radial preload, i.e. a tight, compressive fit produced by insertion of a pin slightly larger than the drill hole. The effect of radial preload is to minimize pin loosening and to seal the pin track so that a potential infection cannot reach the medullary cavity from outside. The amount of misfit between the hole diameter and the pin diameter should not exceed 0.05‑0.1 mm. Such a precise geometric discrepancy can only reliably be ensured by using self‑cutting tips. See Preload
Radiotherapy Treatment of pathological conditions, usually malignant, with
ionizing radiation. It has been recommended in low dosage to discourage
heterotopic bone formation.
Recurvatum: an angular deformity , usually of a long bone, in which the distal part is angulated anteriorly, so that the apex of the angle is posterior.
Reduction
The realignment of a displaced fracture or a dislocated
joint.
Reflex Sympathetic Dystrophy (RSD): – one of the names given to Algodystrophy.
One of the chronic regional pain syndromes. Usually follows an injury, not
always a fracture. Characterised by chronic pain that fails to resolve within
the time commensurate with the injury, swelling of the part, joint stiffness,
alteration in skin colour, texture and/or temperature and associated with
demineralization of the local bone, especially in the bone just beneath the
articular cartilage (subchondral bone).
Refracture: A fracture
occurring at a former fracture site, after the bone has solidly bridged, at a
load level otherwise tolerated by normal bone. The resulting fracture line may
coincide with the original fracture line, or it may be located remote from the
original fracture, but within the area of bone that has undergone changes as a
result of the fracture and its treatment.
Relative Stability: –
see Stability
of fixation
Remodelling
(of bone): The process of transformation of external bone shape (external
remodelling), or of internal bone structure (internal remodelling, or
remodelling of the Haversian system).
Resorption (of bone): The process of bone removal includes the dissolution of mineral and matrix and their uptake into the cell (phagocytosis). The cells responsible for this process are osteoclasts.
Rheumatoid arthritis: a crippling, aseptic, synovial inflammatory disease, usually involving many joints (polyarthritis). Results in an intense synovitis that eventually erodes the articular cartilage and the underlying subchondral (beneath the cartilage) bone.
Rigid
fixation: A fixation of a fracture which allows little or no deformation
under load – see Stability
of fixation.
Rigid implants: In general
implants are considered to be rigid when they are made of metals. The implant
geometry is more important than the physical stiffness of the material. Most
implants made of metal are much more flexible (less rigid) than the
corresponding bone.
Rigidity: This term is
often used synonymously with stiffness. Some (Timoshenko 1941) feel that its use should be confined to
considerations of shear (e.g. at the interface of plate and bone).
Rotator cuff. A musculo-tendinous "hood", or cuff,
comprising the muscle bellies and the aponeurotic tendons of the supraspinatus,
infraspinatus and subscapularis muscles, passing from their origins from the
scapula to their insertions into the tuberosities of the upper humerus.
This sheet of tendinous tissue lies between the head of the humerus and the
undersurface of the acromio-clavicular arch - in the sub-acromial interval.
These muscle play an important role in controlled shoulder movement and in
stabilising the shoulder. A rupture of the rotator cuff allows the head of the
humerus to migrate upward and come into abnormal articulation with the
undersurface of the acromio-clavicular arch, resulting in later degenerative
change.
Sagittal: Literally, it means pertaining to an arrow (sagitta is Latin word for arrow). Bisection of the body in the sagittal plane would divide it into left and right halves, so-called because an arrow fired into the body would normally strike from the front and would pass in a sagittal direction.
Scarf test: A test for acromio-clavicular dysfunction: the patient experiences pain in the acromio-clavicular joint when bringing the forward flexed arm across the front of their body, as if to “toss a scarf” over the opposite shoulder (this movement is called horizontal adduction)
Scoliosis: a spinal deformity in which there is one, or more, curvature in the coronal plane – may be postural or structural. The latter is often associated with rotational deformity. See also Kyphosis.
Second look: Surgical inspection of a wound or injury zone, 24 to 72 hours after the initial management of a fracture or wound.
Segmental:
If the shaft of a bone is broken at 2 levels, leaving a
separate shaft segment between the two fracture sites, it is called a
"segmental" fracture complex.
Sequestrum:
A piece of dead bone lying alongside, but separated from, the osseous bed whence
it came. It is formed when a section of bone is deprived of its blood supply and
the natural processes create a cleavage between the dead and the living bone. A
sequestrum may be aseptic (sterile), as for example beneath a plate when there
has been massive periosteal stripping and then a plate with a high contact
“footprint” applied, killing the underlying bone. This is especially seen if
a plate has been applied to the cortex at the same time that a reamed
intramedullary nail has been inserted. Infected sequestra are formed in chronic
osteomyelitis – see Osteomyelitis.
Shear: A shearing force is one which tends to cause one segment of a body
to slide upon another, as opposed to tensile forces, which tend to elongate, or
shorten, a body.
Shock:
A state of reduced tissue perfusion, usually due to a fall in blood pressure
secondary to hypovolaemia,
overwhelming sepsis (gram negative shock, or “red” shock), or
allergic anaphylaxis
Shoulder examination - see http://www.usask.ca/cme/articles/fmse/index.php
Simple (single) fracture: A
disruption of bone with only two main fragments.
Splinting: Reducing the
mobility at a fracture locus by coupling a stiff body to the main bone
fragments. The splint may be external (plaster, external fixators) or internal
(plate, intramedullary nail).
Split depression: A
combination of split and depression in an articular fracture – see Pure
split and Pure
depression.
Spondylolisthesis: The
Spondylolysis: the presence of a loss of continuity of the pars interarticularis of a vertebral body. This can lead to instability and forward slip of one vertebral body on the one below it - spondylolisthesis
Spondylosis: degenerative change at one or more levels in the spinal column: degenerative intervertebral disc disease
Spontaneous fracture: One
that occurs without adequate trauma, usually in abnormal bone – see Pathological
fracture.
Spontaneous healing: The
healing pattern of a fracture without treatment. Solid healing is observed in
most cases, but malunion frequently results. This is how animal fractures
normally heal in the wild
Stability of fixation:
This is characterized by the degree of residual motion
at the fracture site after fixation (i.e., very little or no displacement
between the fragments of the fracture). In technical terms, stability describes
the tendency to revert to a condition of low energy, but this strict definition
is not adhered to in lingua franca of fracture surgery.
Stability, absolute: The compressed surfaces of the fracture do not
displace under applied functional load. The definition of absolute stability
applies only to a given time and at a given site: some areas of a fracture may
displace in relation to each other whilst other areas of the same fracture locus
may not; different areas may also exhibit different displacements at different
times. Practically, the only method of achieving absolute stability consists in
the application of interfragmentary compression (q.v.). The compression results
in stability by preloading the fracture interface and by producing friction
(Perren 1972).
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 of the implant. Such motion is always
present, but usually harmless, in nail fixation. According to the philosophy of
the AO ASIF group, plate fixation is more reliable if motion can be prevented,
but never at the expense of the biology of the fracture locus – see Biological
fixation.
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 fracture disease – see Stability
of fixation.
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 its Young's modulus of elasticity.
Stiffness and geometrical properties:
The thickness of a structure affects deformability by its third power.
Changes in geometry are, therefore, much more critical than are changes in
material properties - a fact which is often overlooked by non-engineers. Thus,
if flexible fixation is a goal, it can be achieved more effectively and in a
more controlled manner by small changes of implant dimension than by using a
"less rigid" material.
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 present within small fracture
gaps even under conditions where the displacement may not be perceptible.
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 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.
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 is not exceeded, there will be normal tissue function and indirect healing by callus.
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 elongation at rupture.
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 law). Stress protection is often used
synonymously with stress shielding, that is in
a purely mechanical sense. It is often used to characterize bone loss
‑ implying a negative connotation to stress shielding. With regard to the
internal fixation of cortical bone, stress protection seems to play no important
role, compared with vascular considerations – see Stress
shielding.
The early bone loss seen deep
to a plate, which has in the past been attributed to stress protection, can
better be explained on the basis of a denial of blood supply to the underlying
cortex, due to the pressure of the “footprint” of the plate. The resultant
necrotic bone is then remodeled by osteons,
which originate from the well vascularized, adjacent cortex. This remodeling
process is associated with a temporary osteoporosis.
Investigations of late bone loss
under clinical conditions of internal fixation in the human, using quantitative
computed tomography, show very little
residual bone loss at the time of implant removal (Cordey et al. 1985).
In summary, bone may react to unloading but this plays a minor role in internal
fixation of cortical bone fractures.
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 cyclical loading. If a
hole is drilled in a bone and then left empty, this too will result in high mean
stress and the risk of fracture. With the exception of the LCDCP, with its even
strength, most plate holes represent weaker points on the plate than the solid
sections between the plate holes: in a fixation with such a plate, where a screw
hole has been left unfilled in the fracture zone, the empty hole acts as a
stress riser and also produces the risk of fatigue failure, or bending under
high functional load.
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 function of such a plate is to reduce the levels
of peak load passing through the lag screw fixation. Protection is provided by
virtue of the stiffness of the plate. The plate shields the fracture’s primary
fixation with screws – see Neutralization and Protection.
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 medial border
Synovectomy:
Excision of the synovial membrane.
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 best resists compressive load: this bone-implant
composite therefore is ideally suited to resist the bending force.
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 of angular fractures of
young children’s bones (torus fracture).
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.).
It is commonly misused to describe the path created surgically through tissues
by the insertion of an external fixator pin. In that context, the word
“track” should be used (in the sense of its meaning the mark, or trail, left
by the passage of anything – Oxford
English Dictionary).
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 anatomical position, horizontal would be in the
transverse plane. In other words, horizontal is always related to the horizon,
whereas the anatomical planes (coronal, frontal, sagittal, transverse) always
relate to the anatomical position.
Union. Strictly speaking, union means “as one” – as in
marital union, a workers’ union, even national groups, e.g. the United States.
Equally strictly, if a fracture is fixed so that the bone functions as a single
unit, then it has been surgically “united” (osteosynthesis): the bone is not, however,
healed. Bone healing is a process initiated by fracture and continuing until the
bone is restored to its final state by remodeling – this may take years. We
speak loosely of a fracture’s being united, but this is not a discrete event.
What we are saying is that a healing fracture has reached the point in the
process of union when the experienced surgeon estimates that it can withstand
normal functional loads for that patient. Union is, therefore, a judgment,
usually based upon a synthesis of temporal, clinical and imaging information.
This calls into question the validity of “time to union”, which is reported
in so much of the surgical literature as a parameter for the judgment of the
comparative efficacy of different treatments.
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.
A tissue is said to be vascularised if its intrinsic network of blood vessels is
connected to the main circulatory system. Blood vessels may be shut off
temporarily from the circulatory system.. If the connection to the main
circulation is permanently interrupted, or if the vessels present are not
functioning, e.g. obliterated by thrombosis, the tissue is said to be avascular,
or devascularized. We consider a tissue to be non-vascular if there are normally
no functioning vessels, as in hyaline cartilage
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 of the implant from
the neutral axis of the shaft. Such plating is useful in non-union treatment
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 two the main shaft
fragments –see Butterfly
fragment.
Also used to describe a compression fracture of a vertebral body, where the body
has been crushed anteriorly and made wedge-shaped.
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.