Medical Information

Explore detailed information about a range of joint problems and treatments, including medications, surgery, physiotherapy and rehabilitation. Reading this will help you understand more about your own condition. There is also a glossary with explanations of many medical terms used in orthopaedics. You can find out even more by following the links page to other related websites, journals or professional medical associations.

Click on the letter to see the explanation of the medical terms:


  1. A


    abduction movement of a limb or part away from the midline, e.g. abduction at the shoulder moves the arm away from the trunk and out to the side.

    acetabular (socket) ne: acetabulum the deep socket cup or cavity on the side of the hip bone in which the head of the thigh bone fits to form the hip joint

    acetabular cup denoting the man-made replacement socket for one part of the hip joint

    acetabulum the deep socket or cavity on the side of the hip bone in which the head of the thigh bone fits to form the hip joint

    ACI autologous chondrocyte implantation (same as ACT)

    ACL anterior cruciate ligament of the knee

    acrylic (cement) the substance in making up the bone cement. The filling material or grout in a cemented total hip replacement

    ACT: autologous chondrocyte transplantation (same as ACI)

    acupuncture a traditional Chinese method of healing which uses needles inserted into selected points in the body. This treatment may be used for pain relief

    adduction movement of a limb or part towards the midline. At the thumb, adduction allows for 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

    algodystrophy see Reflex Sympathetic Dystrophy , Complex regional pain syndrome

    allodynia pain from stimuli that are not normally painful, or pain that occurs other than in the area stimulated

    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

    anaesthesia loss of feeling in a part or all of the body

    anaesthetic the agent which causes loss of feeling

    anaesthetist the specialist doctor who administers the anaesthetic for the operation

    analgesics a group of drugs that reduces pain

    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. 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. See deformity

    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), or in ankylosing spondylitis, or healed tuberculosis of bone etc

    antalgic literally against pain. Used to describe an alteration of gait, where the duration of the stance phase on one leg 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”

    anti-inflammatories a group of drugs that reduces inflammation

    arthritis wear or inflammation of a joint. Literally, an inflammatory condition of a 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 An operation in which the joint surfaces are excised and the bone ends are joined together or fused which fixed the joint in one position and eliminates any joint movement.

    arthroplasty the formation of a new joint, usually an artificial replacement of a natural articular joint

    arthroscopy the visual examination of a joint through a thin visual telescope. telescopic or “Key-hole” visualisation of a joint space by means of a pencil-like camera passed through the skin and subcutaneous tissue into the joint

    articular fracture – complete the articular (joint) surface is disrupted and completely separated from the diaphysis (mid-shaft of the long bone). The severity of these fractures depends on whether their articular and metaphyseal components are simple or multi-fragmentary. The articular fracture may also be depressed below the original line of the joint: a depressed fracture of the articular surface. The depression may be central or peripheral and may result in joint incongruity, deformity or premature arthritis.

    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: 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.

    atrophic non-union 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)

    autologous tissue which is derived from a patient’s own tissue or DNA

    avascular necrosis Death of tissue; usually bone due to a loss of blood supply in the absence of sepsis, (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.

    avascular: without blood supply

    avulsion detachment by pulling of one part from another eg tendon from bone muscle from tendon, one part of bone from another.

  2. B


    bactericidal capable of killing bacteria

    baker’s cyst a collection of synovial fluid behind the knee joint

    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 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 utilised from the patient or from other persons collected in a central bone bank. It is used to fill defects in bone. 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.

    bone resorption where bone has been removed by the patients own tissue or lost by the tissues reaction to motion and prosthetic loosening

    broad spectrum refers to antibiotics which are active against a wide spectrum of different organisms

    bursa a small collapsed balloon of tissue localised to the subcutaneous tissue over bony prominences to reduce friction (see trochanteric bursitis)

    bursitis inflammation of a bursa

    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 an implant applied in such a manner as to press against a fragment and prevent its axial displacement under compressive physiological load, maintaining its reduction “out to length”, is said to be functioning as a buttress. An example would be a contoured bone fixation plate applied to the upper end of the tibia to prop up the surgically elevated main articular fragment of a tibial plateau fracture, thereby preventing its re-displacement into a position of depression.

  3. C


    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) ð remodelling into woven bone, gaining in strength and stiffness as it does so.

    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.

    capillaries the small blood vessels supplying tissue

    cartilage the dense firm smooth and slippery tissue which covers the end of bones involved in joints. This tissue makes the low friction mobile surface and the weight bearing surface of the joint.

    catheter a tubular, flexible, surgical instrument for withdrawing fluids from (or introducing fluids into) a cavity of the body, especially one for introduction into the bladder through the urethra for the withdrawal of urine

    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 articular cartilage

    chondrocytes chondrocytes: The active cells of all articular joint cartilage, whether articular cartilage, growth cartilage, fibrocartilage, etc. They produce the chondral matrix, both its collagen and the mucopolysaccharides of the ground substance.

    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.

    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 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.

    compression screw see lag screw

    condyle the characteristic side prominence of a long bone which makes a rounded end which forms part of an articulating joint. EG: The medial condyle of the femur at the knee forms the inner half of the joint between the femur and the tibia at the knee.

    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. See direct healing

    Continuous Passive Motion: see C.P.M.

    contra-indications when evidence found which would mitigate against performing surgery. An example of this would be an active infection which would contra-indicate against performing a total joint replacement

    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

    CPM Continuous passive motion is a powered machine which gently moves the knee through a controlled range of motion and facilitates the return of joint movement and helps to prevent stiffness following surgery.

    creeping substitution see blood supply , avascular necrosis

    cup denoting the man-made replacement socket for one part of the hip joint

    cytoplasm the non-nuclear internal substance of a cell

  4. D


    débridement excision of dead tissue. 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. It is also applied to the knee or other arthritic joint where the joint surfaces, edges and debris is removed to restore the joint to a normal anatomical shape albeit degenerative and worn.

    deep vein thrombosis (DVT) A blood clot in the deep veins.

    deformity any abnormality of the form of a body part. The standard surgical convention is that the deformity is characterised by describing the deviation of the distal part from its anatomical position. Certain deformities have specific names – see scoliosis, recurvatum. etc,

    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 charachterised by the absence of callus formation specific to the fracture site.

    dislocation Displacement of a joint such that there is complete loss of contact of the joint surfaces

    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.

    dysplastic (dysplasia) an abnormal development i.e. a dysplastic hip joint – an abnormal shape of the hip joint

  5. E


    ECM: extra-cellular matrix. This is the chemical substance which surrounds the cells and in which they live. In respect of articular cartilage this is the collagen lattice and the entrapped poly – glycoaminoacids which form the bulk of articular cartilage by volume

    effusion Accumulation of fluid within a cavity

    elastic deformation: see plastic deformation

    embolism Foreign body in the blood stream, e.g. blood clot, fat or air

    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.

    epidural anaesthetic this is where an anaesthetic is injected into the space outside the cover of the spinal cord. It is often used in combination with a general anaesthetic. The epidural anaesthetic abolishes sensation to the lower limbs, thus providing pain relief following a total hip replacement.

    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.

    epoxy (cement) The material making up the filling material or grout or bone cement used in a total hip replacement

    erosion The wearing away of a surface

    escherichia coli A bacterial organism

    excision arthoplasty The joint is excised and a gap is created between two joint surfaces

    exostosis A prominent bony growth of bone

    extension the movement of an articulation that causes the relationship between part above the joint and the part below the joint to becomes straighter. An exception is „extension“ of the foot at the ankle (so-called dorsiflexion); dorsiflexion is the better term, in this context.

    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.

    extensor mechanism quadriceps tendon, patella and patella tendon

    extra-articular fracture does not involve the articular surface, but it may be intracapsular (as in fracture of the femoral neck)

  6. F


    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.

    femoral pertaining to the thigh or femur bone

    femur The thigh bone

    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 muscles 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 – complex 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 – wedge 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.

    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 his 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.

    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 A fixation of joint surgically by means of bony apposition to eliminate movement

  7. G


    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.

    general anaesthesia A state of unconsciousness provided by the administration of a combination of intra-venous injection and gases

    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 co-aptation 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.

    greater trochanter the bony protuberance over the upper and outer aspect of the thigh bone.

  8. H


    haemarthrosis bleeding into the joint

    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

    healing In respect of fractures; a 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.

    heparin An agent widely used for preventing clotting of blood

    heterograft see allograft and xenograft.

    homeopathy a type of medicine which is based on the principle that small quantities of medicines capable of producing symptoms are provided for cure of a particular condition

    homograft see allograft and autograft

    horizontal parallel with the horizon: unrelated to the anatomical position

    hybrid hip replacement a cementless acetabular cup and a cemented femoral prosthesis.

    hydroxy-apatite the mineral content of bone (bone ash)

    hypertrophic non-union 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 non-union

    hypnotherapy treatment by means of hypnosis

    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

  9. I


    idiopathic of unknown cause

    impacted fracture see fracture impacted

    impaction bone grafting when the bone is milled into smaller pieces and impacted into defects in bone

    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).

    interposition arthroplasty where the joint surfaces are interposed by a material

    intra-articular within the joint

    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.

    intra-osseous within bone

    intravenous within a vein or veins

    ischaemia absence of blood flow

  10. J


  11. K


    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”)

  12. L


    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.

    Lateral: literally, of, or toward, the outer 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.

    laxity loose

    LCL: lateral collateral ligament

    ligamentous tissue this is the tough tissue which connects one bone to another and resists abnormal movement between the two

    ligaments bands of fibrous tissue connecting bones and cartilage, serving to support and resist unwanted movement in joints

    local anaesthesia the abolition of pain and feeling in a localised area of the body

    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

    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

    low friction arthroplasty (LFA) total hip replacement utilising a plastic acetabular socket or cup articulating with a femoral prosthesis using a small femoral head to reduce friction at the articular interface

    low molecular heparin a type of Heparin utilised in prevention and treatment of deep vein thrombosis

    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

  13. M


    malunion consolidation or healing of a fracture in a position of deformity.

    matrix: tissue scaffold; 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).

    MCL: medial collateral ligament

    medial inner side; 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.

    Meniscus semilunar: usually referred to the similunar shaped piece of fibrocartilage which sits in the medial and lateral aspect of the knee (tibio-femoral joint) which assists in spreading the loading forces across the knee and cushioning the joint for direct impact and premature wear.

    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.

    microfracture articular cartilage repair technique

    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.

    mosaicplasty a technique used to repair localised defects in the articular cartilage repair technique utilising multiple small autologuous osteochondral plugs

    MRI magnetic resonance imaging

    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. A syndrome of excessive pressure and tissue damage within an isolated muscle compartment. Usually of the leg and calf. In the conscious patient, the earliest and most important Treatment is by a 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 again 24 to 48 hours later. Decompressive fasciotomy is an emergency procedure, disturbances of muscular microcirculation that persist longer than 12 hours produce significant motor and sensory deficits as well as myogenic contractures. Good results are generally obtained only if decompression is performed within 6 hours of the onset of compartment syndrome. Limb amputation becomes likely if surgery is delayed beyond 12 hours. 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. Motor weakness may occur 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. 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 is by a 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 again 24 to 48 hours later. Decompressive fasciotomy is an emergency procedure, disturbances of muscular microcirculation that persist longer than 12 hours produce significant motor and sensory deficits as well as myogenic contractures. Good results are generally obtained only if decompression is performed within 6 hours of the onset of compartment syndrome. Limb amputation becomes likely if surgery is delayed beyond 12 hours.

  14. N


    near cortex the bony cortex near the operator and on the side of application of an implant. Usually a term used in relation to plating, interfragmentary screw fixation and tension band wiring. In respect to bending, the convex near cortex contributes little to stability of fixation. When – for example, in wave plate application – the distance between the plate and the near cortex is increased, the bone and the repair tissues gain better leverage.

    neurovascular The system of nerves and blood vessels

    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- 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. anatomy.

    NSAID non-steroidal inflammatory drugs A group of drugs which are not cortico-steroids but have a similar effect on reducing local inflammation and therefore pain, stiffness and swelling. Commonly used in arthritic, inflammatory or traumatic musculo-skeletal pain

  15. O


    OAT osteochondral autograft transfer

    OATS osteochondral autograft transfer system

    open fracture fractures with an overlying, communicating wound of the integument, exposing the fracture site to contamination and the risk of infection. Open fractures are commonly graded according to the severity scale of Gustilo, Mendoza and Williams (J.Trauma 1984) . This scale comprises grades 1, 2, 3A, 3B & 3C, from the least to the most severe soft tissue damage.

    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)

    orthopaedic surgery specialist surgery involving the treatment of diseased or damaged bones and joints of the skeleton

    orthopaedic(s) specialist surgery involving the treatment of diseased or damaged bones and joints of the skeleton

    osteoarthritis this is a degenerative condition of a joint. It is characterized by loss of articular cartilage, reactive subchondral bone sclerosis (sometimes with subchondral cysts) and the formation of 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, or a genetic disposition etc. 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 .

    osteoarthrosis see osteoarthritis

    osteoblast a cell that forms new bone

    osteoblastic producing bone.

    osteochondral bone and cartilage

    osteochondritis dissecans (OCD) separation of cartilage with bone fragment, usually from femoral condyles

    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.

    osteolysis bone resorption which can be localised of diffuse

    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 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. infection (haematogenous osteomyelitis) – usually in children or in the immunologically compromised – or follow an open fracture (post-traumatic osteomyelitis).

    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 osteoblasts lays down concentric cylinders of new bone or osteoid, that matures to form the rings of bone seen in the walls of the Haversian systems of 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

    osteopathy a treatment based on the principle that diseases are associated with the musculo-skeletal system. Treatment may involve massage and manipulation.

    osteoporosis abnormal thinning of bone

    osteoporosis 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

  16. P


    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.

    palmar pertaining to the palm of the hand, e. g. the palmar fascia, the palmar aspect of the fingers

    paraesthesia an abnormal sensation, e.g. pins and needles

    paresis a partial paralysis

    passive movement movement initiated by a doctor, physiotherapist or health worker

    patella kneecap

    patella alta high-riding kneecap

    patella infera (or Baja) low-riding kneecap

    patellofemoral joint (PFJ) joint between patella and femoral trochlea

    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.

    PCL posterior cruciate ligament

    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

    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

    PKR partial knee replacement see Uni-compartmental knee replacement

    plafond (Fr.) literally “ceiling”: used to denote the horizontal portion of tge distal tibial articular surface. See pilon

    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 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. 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.

    PLC postero-lateral corner of the knee. Commonly injured in complex ligamentous knee injuries which rupture the posterior cruciate ligament

    polytrauma multiple injuries to one or more body systems. An Injury Severity Score (ISS) of more than 16 is usually taken to indicate polytrauma.

    popliteal fossa the back part of the knee joint

    porous ingrowth where bone grows into the uneven depressions of the outer surface of the metal shell or femoral prosthesis.

    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. 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. 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).

    primary arthroplasty(ies) the first total hip replacement

    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 on its lateral border

    prophylactic preventive

    prophylaxis measures taken to prevent a disease process, e.g. providing anti-biotics immediately prior to performing a total hip joint replacement

    proprioception: the perception of position of the joint, limb or body as in balancing depends upon the perception of and reaction to the stability of the static position. This interpretation of the local position or change of that position of the joint or limb or indeed of the whole body

    prostheses the artificial implants inserted into the body, e.g. the total hip replacement

    prosthesis the artificial implant inserted into the body, e.g. the total hip replacement

    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.

    pseudocapsule the newly formed tissue surrounding the joint which forms after a total hip replacement

    pseudomonas aeruginosa a bacterial organism

    psoriasis a chronic skin disease. It may sometimes be associated with an inflammatory arthritis of joints

    pulmonary embolus a blockage of the blood vessels in the lung tissue, usually caused by a blood clot originating in the leg veins

  17. Q


    quadriceps muscles the muscles on the front and sides of the thigh. These are termed the vastus lateralis, rectus femoris and the vastus medialis. The lower part of the vastus medialis has transverse fibres and is the area referred to as the vastus medialis obliqius of VMO

  18. R


    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. 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.

    radiological examination X-ray examination

    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). See Complex Regional Pain Syndrome

    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.

    retropatellar behind the kneecap or patella

    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.

    rheumatoid arthritis: an inflammatory condition of the joints affecting the synovial tissue of a joint. It commonly involves several joints in a polyarthritis. Results in an intense synovitis that eventually erodes the articular cartilage and the underlying subchondral (beneath the cartilage) bone, producing joint deformities pain stiffness and may be crippling.

    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).

    ROM range of movement

    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.

  19. S


    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

    self-curing as in superglue

    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

    sigmoidoscopy examination of the rectum and large bowel by means of a flexible fibre optic instrument.

    simple (single) fracture a disruption of bone with only two main fragments. Formerly used to denote a fracture that was not “compound” (or open)

    SLR straight leg raise. To lift the leg from the horizontal position in an exercise

    spinal anaesthetic an injection into the space surrounding the spinal cord abolishing sensation to the lower part of the body and limbs

    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 forward slip of one vertebral body on the one below it. This may be due to congenital elongation of the pars interarticularis of the vertebra, spondylolysis, degenerative joint disease affecting the intervertebral facet joints, and rarely an acute fracture of the pars interarticularis

    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 where very little or no displacement between the fragments of the fracture

    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.

    staphyloccus epidermis a common bacteria colonising the skin

    staphylococcus a bacteria

    staphylococcus aureus a bacteria

    stem the implant which is inserted into the marrow cavity of the thigh bone following removal of the femoral head

    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.

    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

    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.

    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.

    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 under the cartilage

    subcutaneous under the skin

    subcutaneous injections injection inserted into the layer deep into the skin

    subluxation partial dislocation of a joint where part of the joint surface still remains in contact

    subsidence sinkage usually of an implant or prosthesis into the metaphysis of the bone in which it has been implanted

    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. Synovial joint (diarthrodial joint): the commonest form of joint in the body, where two bone end, each covered with hyaline cartilage, articulate, the one on the other. They are bound together by a joint capsule and ligaments. The interior of the joint, other than the cartilage surfaces, is lined by synovial membrane, which secretes synovial fluid as a lubricant and a nutrient transport fluid.

    synovial fluid knee joint fluid

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

    synovial membrane (synovium) inner lining of membrane surrounding a mobile joint. The synovial membrane secretes a lubricating joint fluid.

    synovitis an inflammatory condition of the joints affecting the synovial tissue

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

    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.

  20. T


    tendinitis inflammation of the tendon. This is not an infected or bacterial tendonitis but in absolute terms a sterile tendinosus

    tendinosis an inflammation of a tendon in the absence of infection.

    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

    tibia shinbone

    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

    TKR total knee replacement

    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).

    total hip arthroplasty where both joint surfaces are replaced, that is the acetabular socket and the head of the femoral bone.

    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 anatomical position, horizontal would be in the transverse plane. The anatomical planes (coronal, frontal, sagittal, transverse) always relate to the anatomical position.

    trochanteric bursitis inflammation of the subcutaneous sac localised to the outer and upper prominence of the thigh bone.

    trochlea the joint space at the front end of the femur (articulates with patella)

  21. U


    UKR unicondylar knee replacement (same as partial knee replacement)

    union strictly speaking, union means “as one”. Usually used in reference to bone healing. 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.

  22. V


    valgus an angulation of deformity away from the midline

    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 an angulation of deformity towards the midline.

    vascular injuries injuries to arteries or veins

    vascularity that property of a tissue which reflects the extent to which it has, or does not have, a blood supply

    venogram an investigation where a radiopaque contrast agent is injected into the vein and x-rays are taken to ascertain whether there is a blockage in the lower limb veins

    vertical upright. Perpendicular to horizontal. Derives from vertex, meaning the top, as in the vertex of the skull

    VMO vastus medalis obliqus see quadriceps. The lower most oblique fibres of the vastus medialis muscle on the anterior and medial aspect of the thigh

  23. W


    Warfarin an anti-coagulant agent used in the treatment of deep vein thrombosis

    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.

  24. X


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

  25. Y


  26. Z


    zone of injury the entire volume of bone and soft tissue damaged by energy transfer during trauma