Chapter 5 Fracture Treatment & Other Related Orthopedic Principles

 

 

 5.1 Fracture:

A complete/incomplete break in the continuity of bone or cartilage or both.

 5.2 Mechanics of Fractures

When sufficient force is applied to an object, it deforms the object. Deformation is measured by a force deformation curve.

Bone is not a static module

• - Structural material properties change
• - Bones of puppies bend considerably before breaking
• - Has the ability to absorbe energy through deformation
• - Bones become stronger by becoming stiffer
• - They optimize their shape to resist the forces they are subjected to
• - The principle of bone adaptability to mechanical function is known as Wolff’ s Law

Simply stated: Bone is deposited where needed in response to mechanical stresses 

5.3 Forces on a bone:

Bone undergoes specific failure or fracture associated with different modes of loading when loaded in: 

5.3.1 Tension:

• Fr plane is approx perpendicular to the applied force  Fr plane approx
• 1 to applied force 

5.3.2 Compression:

• Fr plane is generally an oblique angle to applied force 

5.3.3 Torsional:

• Fr is in a spiral plane 

5.3.4 Bending Loads

(High tensile stress on one side & high compressive stress on other): Fr plane originates transversely on tension side with oblique. Fr plane on compressive side. If more than one oblique, Fr plane exists on compressive side, a "butterfly" segment results. 

5.3.5 Bending & Compression Loads

Acentuation of oblique Fr of bending loads with bigger butterfly segments or comminution. The later is due to a complex rapidly applied force. 

5.4 Causes of Fractures:

• a) Direct force applied to bone; 75 to 80% - car accidents
• b) Indirect force - Force transmitted to point of Fr. from other area via a muscle or tendon eg. Fr. femoral neck, avulsion of Tibial Tubercle.
• c) Bone diseases: may weaken the bone so as only a little trauma produces Fr e.g. bone neoplasms, Sec. nutritiona1 Hyperparathyloidsm & Sec. .Nutritional Hyperpaletly
• d) Repeated stresses: Fatigue Fr of Front/Rear foot eg. central tarsal, accessory carpal bone 

5.5 CLASSIFICATION OF FRACTURES

5.5.1 DIRECTION & LOCATION OF FRACTURE:

• a) Transverse Fr: Fr line is at right angle to bone axis
• b) Oblique Fr: Line of Fr diag. to long axis of bone. Fragments tend to slip.
• c) Spiral Fr: Fr. Line is a curve
• d) Comminuted Fr: splintering or fragmentation of bone. Fr lines meet at a common point.
• e) Multiple/Segmental Fr: Bone broken into 3-4 more segments which don’t meet at a common point.
• f) Impacted Fr: Segments driven firmly together
• g) Avulsion Fr: A fragment of bone, which is the site of insertion of a muscle, tendon or ligament, is detached as a result of a forceful pull
• h) Physeal Fr: Fr/Separation occurs at physeal line or growth plate. Seen in young animals.
• i) Condylar Fr: Fr line passes through A condyle.
• j) Intercondylar Fr: Fr line runs between two condyles

5.5.2 PRESENCE OF A COMMUNICATION EXTERNAL WOUND:

• a) Closed fr: Does not communicate to outside
• b) Open fr: Communicate to outside with contamination/infection 

5.5.3 EXTENT OF DAMAGE:

• a)Complete Fr: Total disruption of bone usually with displacement.
• b) Green stick Fr: One side of bone is broken and other is bent. Seen in young animals. Displacement is minimal.
• c) Fissure Fr: One or More fine cracks penetrate the cortex in spiral or longitudinal direction. Periosteum is still intact

5.5.4 STABILITY FOLLOWING ANATOMICAL REDUCTION:

• a) Stable Fr: FraGments interlock and resist shortening forces. eg. transverse, GreensticK, impacted.
• b) UnstaBle Fr: Fragments slide by each other out of position. eg. oblique, spiral 

5.5.5 CLASSIFICATION OF OPEN FR:

• a) 1st DeGree: occurinG from within, with Fr bone penetrating the sKin at the time of injury
• b) Second Degree: occuring from outside, with contusion of the skin and soft tissues
• c) Third Degree: occuring from outside with extensive skin, nuscle and possible nerve damage with a comminuted fracture. Damage is potentially difficult to treat. 

5.5.6 PHYSEAL INJURIES, CLASSIFICATION OF:

• a) Salter I: occurs transversely through the region of cartilage hypertrophy and degeneration.
• b) Salter II: extends to metaphysis
• c) Salter III: extends from hypertrophied cartilage through germinal cell layer into epiphysis
• d) Salter IV: Longitudinal Fr through metaphysis,physis & epiphysis into the joint
• e) Salter V: Fr crushes the chondroblastic cell layer 

  5.5.6.1 Diagnosis of fractures:

  • - GPE
  • - Orthopedic Exam. i.e. History, clinical signs, radiograms etc.
  • Clinical signs
  • - Pain or tenderness
  • - Deformity
  • - Abn. mobility
  • - Local swelling
  • - Loss of function
  • - Crepitence 

5.6 BONE HEALING

• - Has been arbitrarily devided into 3 overlaping phases which parallel wound healing. 

  5.6.1 INFLAMMATORY PHASE:

  • - Trauma, due to damage to the bone, periosteum, surrounding muscles, blood vessels etc, results into hematoma formation in between fracture ends, medullary canal and underneath the periosteum.
  • - This vascular damage deprives the osteocytes of the nutrition and hence causes them to die as far back as the junction of collateral channels.
  • - Hence bone ends in immediate vaccinity of Fr. are dead
  • - They along with severely damage periosteum marrow & surrounding soft tissue contribute to the necrotic tissue formation which elicits an immediate & intense acute inflammatory response.
  • - Inflammatory response is accompanied by vasodilation, plasma exudation and acute edema of the region, resultant to chemical mediators of inflammation.
  • - Inflammatory cells, PMN’s & maclophages etc, migrate to the site
  • - As the acute inflammatory response subsides the next phase begins

  5.6.2 REPARATIVE PHASE:

  • - Hematoma organizes and provides fibrin scaffold for Migration of pleuripoten cells of mesenchymal orgin
  • - The pleuripotential cells may originate from vascular endothelium, nucleated red cells, wandering cells. Endosteal cells & cells from cambium layer of the periosteum. This happens in the first 3-4 days.
  • - These cells migrate to the fracture site with ingress of capillaries and form a callus composed of fibrous tissue, cartilage and blood vessels in 4-9 days.
  • - The callus quickly envelops the bone ends and leads to a gradual increase in stability of the fracture fragments. This envelop is referred to as external (periosteal) bridging callus and can lead to formation of a mature callus.
  • - At the same time formation of medullary bridging callus and intercortical uniting callus takes place.
  • - The stability of the fracture fragments dictates the mode of osteogenesis at the fracture site. Under conditions of good blood supply and excellent stability most bone is formed directly from mesenchymal cells.
  • - Under less stable conditions fibrous tissue is formed which mineralizes & undergoes necrosis and is reabsorbed by macrophages & in its place bone is laid down.
  • -- Under greater instability and or distraction mesenchymal elements lay down cartilage where chondrocytes hypertrophy, extrude ground substances which calcifies resulting into isolation of chondrocytes from their nutrition source and death. As this calcified cartilage disintegrates obteoblasts and capillaries invade (periosteal bud) the remnants of irregular cartilaginous network thus mimicking endochandral ossification.
  • - In many instances, all of these processes may help form the bony callus which unites the fracture ends. 

  5.6.3 Remodeling Phase:

  • - Callus undergoes remodeling along lines of functional stress in accordance with Wolff’s Law
  • - Continues for years (6-9 yrs)
  • - Osteoclastic resorption of poorly placed trabeculae occurs
  • - Simultaneously new bone is laid down that corresponds to lines of force or stress
  • - Results in a bone which is as near to normal as possible in its functional demands.

  All the events mentioned above are associated with secondary bone healing. 

5.7 PRIMARY FRACTURE HEALING:

Areas of osteogenic potential

• - periosteum
• -- endosteum & medullary cells
• - hematoma
• - cortical ends

Primary Fr. Healing occurs provided Fr ends are:

• - readily apposed
• - regidly apposed
• - regidly fixed
• - no vascular disturbance 

  5.7.1 GAP Healing:

  Fr. rigidly fixed but has small gaps between fracture ends.

  • l) First stage: Gap filled with new bone laid down directly along vascular elements with its orientation being transverse to long axis of the bone diaphysis
    • - Necrotic areas of bone present on either end due to interruption of vascular circulation in Haversian canals
  • 2) Second Stage: Haversian, remodeling begins with formation of resorption cavities that penetrate longitudinally through necrotic fragments and approach the newly formed tissues with in the Fr gap.
    • - Resorption cavities are formed by groups of osteoclasts that form a cutting cone.
    • - Resorption cavity is lined by osteoblasts precursor cells and contain a B.V. in its center
    • - Osteoblasts form an osteoid
    • - Resorption cavity is filled by layers of new bone and become an osteone
    • - osteones advance parallel to long axis of the bone across the Fr & healing is completed 

  5.7.2 Contact Healing:

  • - Primary bone formation under rigid fixation and tightly opposed bones
  • - Like second stage of gap healing
  • - As there are no gaps present the cutting cones of osteoclasts advance across the fracture site and result in resorption cavities
  • - Capillary loops in resorption cavities are accompanied by osteobastic precursor cells which line the cavity
  • - Precurssor cells become osteoblasts and produce osteoid
  • - Resorption cavity gets filled up by layers of new bone around the central blood vessel
  • - Osteone is formed
  • - Hence contact healing has taken place by haversian remodeling, and simultaneous union & reconstruction of the Fr. ends.

 5.8 FACTORS INFLUENCING BONE HEALING:

5.8.1 Local Factors:

5.8.1.1 Degree of local soft tissue trauma

• - more trauma, retarded bone healing
• - as mesenchymal cells are utilized to repair soft tissue damage
• - Hematoma diffuses into adjacent soft tissues
• - Extensive disruption of blood supply so increased devitalized tissue

5.8.1.2 Degree of bone loss:

• - Loss of bone substance or excessive distraction Oc fragments leads to compromised ability of the cells to bridge the gap

5.8.1.3 Type of bone involved:

• - In cancellous bone repair is rapid due to many points of bone contact which are rich in blood supply & cells
• - Cortical bone heals through primary or standard secondary healing through ext. callus formation.

5.8.1.4 Degree of Immobilization:

• - Inadequate mobility control leads to delayed or non union as motion disrupts the initial fibrin scaffoldino and external callus fails to form
• - O2 tension & acidosis

5.8.1.5 Infection:

• - If infection is superimposed on a fracture the local forces are mobilized to wall off & eliminate the infection, hence healing is retarded or is absent

5.8.1.6 Avascular necrosis:

• - If one fracture segment is avascular healing is retarded or absent
• -- If both fragments are avascular healing is very poor or mostly absent 

5.8.2 Systemic Factors:

5.8.2.1 Age:

• - elderly mature animals heal at a slower rate than younger animals

5.8.2.2 Hormones:

• - corticosteroids inhibit the union where as growth hormones stimulate fracture healing
• - Thyroid hormones, calcitonin Insulin, vitamin A&D; anabolic steroids are reported to enhance bone healing
• - Where as Diabetes, castration hypervitaminosis A & D and ractitic state retard bone healing

5.8.2.3 Exercise & Local stress:

• - Denervation retards bone healing probably by diminishing stress across fracture line
• - Exercise increases the rate of repair of bone 

5.9 HEALING RELATIVE TO DIFFERENT KINDS OF STABILITY FOLLOWING MIDSHAFT EXPERIMENTAL OSTEOTOMIES OF FEMUR 

5.9.1 No fixation:

• - There was marked overriding
• - Union When occurred was almost entirely dependent upon the organization of the fracture hematoma.
• - Hematoma was huge & surrounded the fracture ends
• - Hematoma differentiated into cartilage which attempted to form a bridging callus which when completed was slowly converted to bone by endochondral ossification
• - Delayed union & non-unions were very common
• - The earliest union occurred at 14 weeks posttruama or Fr. 

5.9.2 Loose fitting Intramedullary fixation:

• - Rotation of fragments around the fixator
• - Marked periosteal reaction extending the full length of the diaphysis on both fragments to within one cm. of the fracture line where periosteum has been traumatized
• - Cortex beneath the periosteal reaction under went extensive remodeling and eventually by 3 weeks resembled a cancellous structure
• - Presence of I.M nail inhibited the formation of endosteal callus
• - Bone formation at Fr. site took place by organization of hematoma and endochondral ossification
• - When motion was more pronounced the cartilaginous bridge never completed. A cleft developed at the level of fracture extended in soft tissue which in older specimen was lined by synovial like tissue complete with villi
• - Nonunion or delayed unions ensued

5.9.3 Tight fitting I.M. nails:

• - All rotary motion was eliminated
• - Periosteal reaction was limited to 2-3 cm of the fracture ends
• - No endosteal callus formed
• - Bone formation occurred in fibrous stroma of the hematoma without going through cartilage phase
• - A very little endochondral ossification takes place
• - This type of healing may be seen in cases of stack pinning simple I.M. pins along with Krischner apparatus 

5.9.4 Bone Plate: no compression versus compression:

• - Minimal periosteal reaction in compressed
• - More periosteal reaction in non-compressed
• - Marked endosteal reaction at three weeks and accounted for early union
• - Primary healing from cortical elements took place

Relatively very little cartilage was found in medullary cavity callus of the compressed fracture

Mechanial tests show that fracture uniting by closed reduction and large periosteal callus by the end of first month would provide superior stiffness & strength than to those fractures compressed by tension band plates

• - However tension band plates approach the same strength & stiffness of the above group in 3 months.
• - The mode of osteogenesis is dependent on the stability of reduction of the bone fragments. Periosteal callus is directly proportional to instability. 

5.10 DELAYED UNION & NON-UNION

5.10.1 Delayed Union:

• -When a fracture does not heal in an arbitrary normal healing time
• - The normal time may vary according to age, species, breed, bone involved, level of fracture & type of fracture.
• - Radiographically the Fr line is visible, there is minimal callus formation & Fr. site has a feathery or woolly appearance. 

5.10.2 Non-Unions:

• - An un-united Fr. where repair process has totally ceased
• - No osteogenic activity present
• - It is one end or delayed union
• - Radiographically Fr. Line is visible with no callus formation or union 

5.11 LASSIFICATION: 

5.11.1 VIABLE: i.e. capable of biological reaction

i) Hypertrophic or elephants foot from

• - There is abundance of callus with a profusion of B.V.
• -- Fr. Gap is occupied by fibro cartilage
• - Cause is usually insufficient stabilization or premature weight bearing

ii) Slightly Hypertrophic or Horse hoof form:

• - Milder form of hypertrophic non-union with poor callus or slight increased density of the fragment ends
• - Frequently occurs under a plate fixator where Fr is some what unstable. Callus & plate are not sufficient to stop motion

Metal or screws fail and become loose

Oligotrophic Non Union:

• - No callus formed
• - Results from great displacement of fragments too much traction or lack of anatomical reduction or apposition
• - Fr. ends round off, become shorter through resorption c& decalcify
• - May be joined by fibrous tissue 

5.11.2 NON-VIABLE: i.e. incapable of biologic reaction

i) Dystrophic non union:

• - Presence of an intermediate bony fragment, with conpromized blood supply, which has healed to one side but not with other main bony fragment.

ii) Necrotic Non-Union:

• - Presence of numerous intermediate fragments with insufficient blood supply
• - Fragments are more radiopaque
• - Maybe further away from main segments

iii) Defect:

• A segment of bone is lost or missing

iv) Atrophic

• - End result of top three
• - Fragment ends resorb inactivity leads to osteoporosis atrophy 

  Incidence of Non Union:

  • - About 5% in human surgery
  • - Less in animals
  • - Radius & Ulna 60%
  • - Tibia 25%
  • - Femur 15% 

5.12 CAUSES OF DELAYED/NON UNION

• - Inadequate reduction
• - Inadequate uninterrupted immobilization
• - Impaired blood supply
• - Infection
• - Loss of fragments
• - Metabolic/Nutritional disturbances
• - Local neoplagia
• - Age/Osteoporosis/disuse
• - Failure of osteogenesis

a. advised open surgery

• - Loss of initial Fr. hematoma
• - Stripping of periosteum
• - Stripping of soft tissue attachments of the bone
• - segment/fragment
• - Reaction of metallic Implants
• - Too much implanted material
• - Use of antimetabolites,cytotoxic or steroidal drugs etc 

5.13 PATHOGENESIS:

• - Intrafragmentary strain levels in the tissues of healing fracture show that small gaps require very little motion to disrupt the tissue where as larger gaps may allow for larger amounts of motion before tissue disruption occurs.
• - In classical fracture healing (secondary bone healing) the granulation tissue can elongate approximately 100% before rupture. As granulation tissue is replaced by cartilage, elongation property is reduced to 10% before rupture. Bone has elongation of 2% to rupture
• - Hence in primary bone healing (under rigid immobilization) small amount of motion has more harmful effect. 

5.14 CLINICAL SIGNS:

• --Motion at fracture site
• - Varying degree of pain
• -- Occasional/rare use of leg
• - Muscle atrophy 

5.15 DIAGNOSIS OF DELAYED/ NON UNION:

Clinical signs, History & Radiographs 

5.16 TREATMENT:

Aim is to improve the local physiological and mechanical environment so as to allow fracture healing to proceed.

5.16.1 TRADITIONAL THERAPY:

5.16.1.1 Compression without bone graft:

• - When adequate reduction and alignment of the fracture ends were achieved initially and some evidence of callus at fracture site is present, compression (platino) will achieve healing within 6-12 wks. 

5.16.1.2 Compression with bone graft:

• - When during initial repair alignment & fixation was inadequate then fracture site is scraped off, of the fibrous & cartilage components. Bones are anatomically aligned & seeded with cancellous bone graft & immobilized. Healing will ensue.

5.16.1.3 Electrical Stimulation Therapy:

• - Direct electrical stimulation with an electrode placed into the non union site as well as non-invasive technique using electromagnetic fields & capacitive coupling are new modes of therapy .
• - Bone resorption occursat-anode (+electrode)
• - Bone deposition occurs at cathode (-electrode)
• - Current levels used are 5 RA to 20 UA <5 UA fail to deposit bone >20 UA cause bone necrosis
• - Three major devices approved by FDA for use in human osteogenesis are:
  • i) Direct current stimulator (Zimmer In)
  • ii) Inductive coupling (Electro-Biology N.J.)
  • iii) Direct current; completely implantable stimulator (Electronics Prop. LTD. Wis)
• - Overall success rate of 80-37% has been reported for treatment of non-unions is man 

5.17 BONE GRAFTING/TRANSPLANTATION

• - May be the critical factor in the out come of fracture repair
• - Provide osteogenic potential or on a limited extent mechanical advantage
• - Cancellous graft is the most commonly employed type
• - Cortical bone employed where mechanical advantage is also needed

  5.17.1 GREAT TERMINOLOGY

  • a) Implant: Nonviable material
  • b) Graft: Viable transfer of living cells
  • c) Osteoconduction: From recipient bed, capillary ingrowth occurs into the
    • a) fresh autograft or in
    • b) bony frame work or scaffolding of dead preserved graft
    • c) Osteoinduction: represent a process (osteogenic cells or chemical) in which unspecialized mesenchymal cells may differentiate into bone
    • d) Creeping substitution: Bone remodeled by osteoclastic resorption and creation of new vascular channels/Haversion systems from the grafted material

  5.17.2 CLASSIFICATION: 

  5.17.2.1 Autograft

  Tissue transfer in the same animal

  • Isograft - Transfer between genetically identical twins
  • Allograft - (Homograft) Transfer between genetically different individuals of the same species
  • Zenozraft - (Heterograft) Transfer across species

  5.17.2.2 Orthotopic graft:

  • Transfer to an anatomically appropriate location.
  • Heterotonic graft: Transfer to an inappropriate location

  5.17.2.3 Cancellous bone graft:

  • Harvested from the cancellous areas of the body Cortical bone graft: When a whole cortical cylinder or cortex alone is transplanted
  • Corticocancellous bone graft: When cortical & cancellous components both are grafted
  • Osteochondral graft: bone along with articular cartilage is transferred
  • Composite graft: Fresh cancellous bone added to a preserved cortical allograft and transplanted

  5.17.2.4 Fresh bone graft:

  Freshly harvested unstored bone graft, direct transfer from donor to recipient

  Preserved bone graft: which have been stored in bank and transferred to recipient when and if needed. Graft is preserved as follows.

  • -- freezing
  • - freezdrying
  • - Irradiation
  • - Autoclaving
  • - Chemical preservation
  • - Cell death occurs during preservation and graft acts as a space filler or scaffold for the ingrowth of new bone either through osteoconduction or through creeping substitution

  5.17.2.5 Viable graft:

  fresh graft; autogenous or & allogenic (Cancellous & cortical)

  Nonviable graft: Allogenic & xenogenic preserved graft

  5.18.3 MECHANISM OF CANCELLOUS GRAFT INCORPORATION

  • - Blood clot & Hemotoma provide the initial environment for the graft
  • - Later followed by cellular response i.e appearance of lympilocytes plasma cells, mononuclear cells.
  • - By 7 to 10 days inflammatory response has subsided. There is perfuse vascular response and by 2 wks there is presence of fibrous tissue and entire graft has been vascularized
  • - Predominant cells at this time are osteoblasts which line the scaffold presented by the trabeculae of the graft and deposit a seam of osteoid that surrounds & entraps the original dead bone
  • - Later is eventually resorbed by osteoclasts
  • - Finally the cancellous graft is completely remodeled and replaced by new bone

  5.18.4 INDICATIONS FOR CANCELLOUS BONE GRAFTING

  • - Promote healing in delayed Unions nonunions & osteotomies
  • - Joint arthrodesis
  • - Multiple or comminuted Fr
  • - Filling voids in the bone
  • - Old, debilitated animals
  • - Osteomyelitis/Infections

  How Bone Graft Helps:

  • - Stimulates proliferation of osteoblast precursor cells
  • - Provides a scaffold
  • - Transplanted cells may provide nidus for bone growth (10%)

  Collection of autogenous Cancellous Bone Graft

  • - "Strict asepsis is a must"
  • - Often used sites of collection are:
  • - Proximal Humerus
  • - Proximal Femur
  • - Proximal Tibia
  • - Iliac Crest Corticocancellous
  • - Ribs grafts
  • -- Site is routinely prepared
  • - A hole is made in one cortex at the designated site
  • - Cancellous bone is scooped out with a curette
  • - Graft is collectedin a blood soaked sponge, held in a

  container & kept covered .With a R/L moistened gauze sponge until transferred to recipient bed

  • - Lay the graft in a relatively dry bed
  • - Don’t pack the graft too tightly
  • - Suture the muscles or sclerotic tissue around it, to keep it in place

  5.18.5 VARIOUS WAYS BONE GRAFTS ARE USED

  • i) Cancellous graft as is
  • ii) Bone chip Graft-cortical
  • iii) Cancellous & cortical chips mixed
  • iv) On-lay bone graft
  • v) Sliding in-lay
  • vi) Tubular or full cylinder diaphyseal graft 

5.19 ORTHOPEDIC IMPLANTS & BIOMATERIALS

• - Stainless steel alloys constitute about 60% of the implants used in USA
• - The primary stainless alloy recommended for manufacture of orthopedic implants is American Iron & Steel Institute (AISI) type 316 L.
• - 316 L is an improvement over l8-8 stainless steel alloy commonly used for Household table Ware
• - Mainly there is addition of Molybdenum (3%) and reduction of carbon (0.03% MAX)) This makes it more resistant to corrosion
• - 12% nickleis added to maintain its structural stability & strength

Chemical Composition of 316 L

The finished product or implant is given a shine and protected by a layer of oxide (nitric) that acts as an electric resistor to retard the anodic dissolution by metal cations and hence reduces corrosion

Corrosion occurs due to metal transfer from orthopedic tools & equipment to the implant, destruction of oxide layer, mixing of various metals in the alloy leading to galvanic reaction, corrosion and other surface irregularities like pits or crevices.

Thus metallic devices for fracture fixation should be removed whenever the implant has done its job e.g. clinical healing has taken place.

Implant removal:

INTERACTION BETWEEN IMPLANT & BODY IN FR. RX

5.20 PRINCIPLES OF FRACTURE RX

Pre-requists:

• - A stable patient
• - A correct diagnosis
• - Thorough & complet planning in terms of surgical approach, instruments & equipment, advantages, disadvantages & limitation of various methodologies and alternatives available for repair

Objectives:

• - To have a patient rehabilitated & returned to normal function as quickly as possible
• - Restoration of normal bone length and perfect alignment
• - Immobilization of the fragments as above till healing has taken place
• - Mobilization of all joints & gentle handling during, surgery of all soft tissues (ligaments, tendous, muscle & periosteum) to prevent muscle atrophy compromised blood supply, joint stiffness (due to capsular fibrosis, contracture & disuse atrophy of articular cartilage) & Fr. disease .
• - Passive motion to be encouraged in immediate post-op till active motion can begin

  5.20.1 CARDINAL RULES OF FRACTURE REPAIR

  5.20.1.1 REDUCTION:

  • - Refers to replacing the fractured bone segments in their original anatomic position
  • - When a fracture occurs, all muscles, flexors and extensors contract maximally thereby causing overriding and shortening of the bone
  • - In addition, trauma and injury of the surrounding soft tissue further increases the spastic contraction of the muscles.
  • - Hence to achieve normal anatomical alignment of the bone segments, an early reduction under conditions of optimum muscles relaxation be attempted
  • - The secret of reduction is the application of continual steady pressure over a period of time

    5.20.1.1.1 Closed reduction:

    It is achieved by:

    • - Application of traction; countertraction, bending, levering, and other manipulative means
    • - Muscle fatigue and relaxation is achieved with balanced anesthesia and use of traction with Gordon extender and by hanging the extremity against patients own body weight

    5.20.1.1.2 Open reduction:

    • - Most commonly employed technique specially for complicated or unstable fractures
    • - Fragments are reduced and aligned after making an appropriate exposure of the bone segments under direct vision.
    • - It is achieved by the application of traction, counter traction, rotation, levering with bone forceps, osteotomes and other equipment
    • - Follow good surgical practice while making an approach to the bone eg.
    • - Gentle handling of soft tissues
    • - Follow normal muscles or fascial plane separation
    • - Avoid cutting into or through major blood vessels or nerves
    • - Preserve soft tissue attachments to the bone
    • - No periosteal stripping

  5.20.1.2 IMMOBILIZATION/FIXATION

  • - Means keeping the already anatomical reduced bone fragments into apposition so there is no motion at the fracture site
  • - Hence the bone must function, as it was prior to fracture, as a single unit and early ambulation is possible. 

    5.20.1.2.1 Methods of Fixation (classification):

    I a) Limb splintage principle: eg. coaptation splints, casts, slings, modified Thomas splint ,Mason metasplint or other casts

    • b) Bone splintage principles: eg. External skeletal fixation/Krishner splint, Intramedullary pins, cross pins, bone screws, bone plates tension band wire, cerclage & hemicerclage wire.

    II a) Closed reduction with external fixation eg. casts, splints.

    • b) Open reduction with external fixation
    • c) Ext. skeletal fixation with open or closed reduction & Immobilization achieved through pins, clamps side bars.
    • d) Internal fixation open or closed & Immobilization with IM pins, nails, bone screws, bone plates & wires etc.

    III a) Closed reduction & external support eg. coaptation splint,K.E. apparatus etc.

    • b) Internal fixation alone eg. bone plate, screws, cross pins etc.
    • c) Internal fixation with secondary ext. support
      • - Internal fixation with minimum ext support eg. modified Robert Jones, valpaue sling, spica, Dove tail bandage
      • - Internal fixation with heavy reliance on ext. support eg. casts, K. E. apparatus etc 

    5.20.1.2.2 Selection of method of fixation depends upon:

    • - Age of the animal eg. young versus old
    • - Size: A small top poodle with a comminuted diaphyseal Fr. of femur may be managed by a 2.7 mm bone plate where as a large standard poodle may require a 3.5 mm. plate

    Activity:

    A small indoor dog with Fr. femur may be managed by IM pin where as same type dog housed outdoors may require more stable fixation eg. a bone plate.

    Location of Fracture:

    • Pelvic Fracture require bone plating over IM pinning or wiring
    • Supra condylar Fr: require cross pinning or other means fixation than bone plating

    Type of Fracture:

    A bad open comminution may be better managed with K-E apparatus than an Internal fixator

    Degree of soft tissue damage:

    A gunshot wounds better manages by KE apparatus than internal fixator

    Neutralization of forces acting on the Fracture:

    Any methodology chosen must cousen must counteract the forces exerted on the bone or fracture line i.e. rotation, bending, shearing and fragment opposition.

    Ability of Various Implants to Neutralize Fr. Forces

    Implant	Rotational	Bending	Shearing	Fragment Appos
    Single I.M. pin	---	+	---	---
    Multiple I.M. pin	+	+	-	-
    Bone Plate	+	-	+	-
    Krischner splint	+	+	+	-
    Cerclage wire	(+)	+	(+)	+
    Lag screw	-	-	-	+

5.21 ORTHOPEDIC EQUIPMENT

Besides general instrument pack (basic) the orthopedic equipment often required is:

5.21.1 General:

• - Retractors: Army - Navy, Rake, Senn. Hohman, Gelpi, Weitlaner
• - Bone holding Forceps: Richards bone clamp, Ker Verbruggee & reduction
• - Hand drills: Steinmann pin chuck, Rotary drill
• - Bone rongeurs & cutter, currettes
• - Osteotome & chisel & mallet
• - Periosteal elevators
• - Wire pliers, forceps & twister, cutters
• - Pin cutters

5.21.2 Pinning equipment

• - Pins assorted sizes: 3/8", 1/4",3/16",5/32",9/64", 1/8,7/64", 3/32", 5/64", .062", .045", .035".
• - Pin vise/chuck
• - Pin cutter

5.21.3 Wiring equipment:

• - Orthopedic wire: 18_ 20, 22, gauze
• -- Wire twister /tightener
• - Wire pliers & cutter
• - Wire passer
• - Drill & pins to drill holes

5.21.4 Plating & screw equipment:

• - Assortment of plates: eg. ASIF 4.5_ 3.5 2.7 systems
• - Assorted screws: eg. ASIF 4.5;3.5, 2.7; cortical 4.0 & 6.5 mm cancellous
• - Assorted washer & nuts
• - Power drill or hand drill
• - Drill bits: eg. 4 5 screw -->3.2 bit; 3.5 screw ---> 2.0 2 7 screw, -> 2.0 bit
• - Drill guide: eg. DCP: > Neutral (green) Compression (yellow)
• - Depth gauzes
• - Bone Taps for non-self tapping screws
• - Tan sleeves
• - Screw drivers
• - Templates
• - Countersinks
• - Plate bender &Torsion bar

5.21.4 Orthopedic Companies:

Richards Mgf. Memphis TN; Kirschner, Aberdeen Maryland; Synthesis Wayne, PA; Zimmer, Warsaw, IN; OEC, Bourbon,IN

5.22 FRACTURE TREATMENT

5.22.1 BONE SPLINTING PRINCIPLES:

A. Ext. Pin splints:

• - Dr. Stader designed the first veterinary ext. pin splint in mid 30's.
• - Most common ext pin splint was designed by Dr. Ehmet in the late 40's and is marketed by Kirschner Mfg. Co. as the K-E splint.

A1. K-E Splint components:

• - Fixation pins: Trocar pointed steinmann pins, usually non-threaded. Single point small pins: 5/66" (1.95 mm) Diameter: Medium pins: 3/32" (2.38 mm); 1/8" (3-17 mm), Large Pins: 3/16 " (4.78 mm); 1/4 (6.35 mm)

A2. Ext. Fixation Rod/bar or connecting rod/bar

• Small Rod: 1/8" (3.17 mm) diameter
• Medium: 3/16" (4.72 mm) diameter
• Large Rod: 7/16" (11.02 mm) diameter

A3. Fixation Clamps

Single: Small, Medium, Large

Double: Small, Medium, Large

• - Krischmer Co. Manufactures and sells them as small, medium & large sets
• - These clamps do accept regular Steinmann pins as fixation pins & connecting bars.

5.23 CLASSIFICATION OF K-E APPARATUS (Heirholzer)

5.23.1 Depending upon configuration:

• Type I: Half pin: fixation pins pass through one skin surface & both cortices. Connecting bar(s) on one side
• Type II: Full pin/thru-thru: fixation pins pass through both skin surfaces & both cortices, connecting bars placed on either (opposing) sides
• Type III: Combination of type I, II: i.e Half & full pin each. Each system is interconnected to creat-three-Dimensional or a triangular frame

Detailed configuration can be devised with one's imagination. Some time a configuration may be devised and described along with the 'type', eg.

Type I: 2 to 3 pins: single bar

• 4 to 6 pins: single bar
• # of pins: double bar
• # of pins: Double clamp, original tech.

Type II: 2-6 pins, standard technique

• modified, 2 full pins, 2-4 half pins

Type III: 3 dimensional standard

• # of pins thru-thru; # in half pin

5.23.2 As indications:

• l) Adjunct to other internal fixation: to prevent axial rotation or/and collapse of fracture site eg. IM pin, wire, cross pin etc.
  • - can be removed in 3-5 wks ie. when callus becomes strong or organized to prevent rotation or collapse.
• 2) Primary fixation: in Hypertrophic non-unions (in closed blind manner)
  • - Atrophic non -unions open reduction manner with decortification & bone grafting
  • - In severe communitions when exacting fixation is not possible in closed reduction manner
  • - open gunshot or infected fractures
  • - corrective osteotomies
  • - stable/non-stable fractures
  • - mandibular fractures
  • - Type II & III only below the stifle &elbow.
• 3) Arthrodesis along with cross pinning
• 4) Leg lengthening procedures

5.23.3 Advantages:

• i) Atraumatic: does not invade or occupy the fracture (war zone) area
• ii) Can be used closed
• iii) Simple & quick
• iv) Versatile alone or with other fixators eg. configuration
  • - 2 lag screws & pin (IM) cannot work whereas
  • - 2 screws & KE can
  • - IM Pin & KE can
• v) Adequate skeletal fix without the physical presence of metal at Fr. site

5.23.4 Disadvantages:

• l. Strength of fixation - not as great as with certain other devices.
  • - So use with caution on femorals & Humoral Fr in large dogs
• 2. External Device: Infection around pins
  • - Requires additional care of the protruding appliance

5.23.5 Principles of Application:

• - Asepsis
• - Normal anatomical reduction. Maynot be perfect during closed application/reduction
• - Pins must be maximally spaced in each segment
• - Reduce pin group separation
• - Minimize pin length
• - Minimize length of connecting bars
• - Pins must penetrate both bone cortices
• - Clamps as close to skin as possible
• - Use adequate size pins (not more than 30% the diameter of the bone) & connecting bars
• - Insert without causing thermal necrosis
• - No distortion of skin or underlying muscles during insertion
• - 3 pins in each segment given 50 to 100% more strength in compression, bending & torsion than 2 pins.
• - More than 4 pins per segment gives insignificant advantage in above (stiffness) terms.
• - Most common technique of application is type I & or type II.

5.23.6 Application of type I Half-pin-splints:

Standard Procedure (4 pins, 2 short bars & conn bar):

• - Paired pins are inserted in each segment at an angle of 35-450 .
• - Each pair is connected with a short-bar one double clamp & 2 single clamps
• - Connect the 2 single bars through the double clamps to a connecting bar

Advantage: Requires least amount of sophistication in pin placement but is bulky

• - To increase strength 2 connecting bars maybe used

Brinker's Modification:

• - Reduce the fracture (open or closed)
• - Miaintain in reduce position during insertion of fixation pins
• - Inset minimum of 2 pins in each fragment at same plane
• - Pins must cross one skin & 2 cortices and must be inserted at 35-45 to each other
• - Place the proximal (l) & Distal (4) pins relatively near the end of the bone.
• - Attach the connecting bar with four clamps
• - Tighten the clamps on the two end pins
• - Insert the center 2 pins through clamps & tighten all clamps
• - The splint is covered with gauze & tape
• - In open reduced fracture splint is applied away from incision line.

Advantage Over Standard Procedure:

• -- Aligns all 4 pins in one plane & connected by one single connecting bar
• - Hence mechanically more stable with less tendency to loosen or twist (as connecting bar anchored at 4 places) than standard method where connecting bar attached at only one point in each segment (2 places total)
• - Less equipment; bulk & cost etc.
• - Provides elastic rather than rigid skeletal fixation. Hence this controlled mobility provides enhanced clinical fracture healing through exuberant periosteal callus formation.

5.23.7 Type II (Full pin splintage) Standard Type II:

• - All fixation pins are driven through both skin surfaces (skin bone-skin) so that fixation bars can be placed on both (opposing) sides of the bone.
• - Provides better support than type I i.e. 20-50% more stiffness over type I
• - Fixation pins are driven perpendicular to the bone or at slight angle
• - Later prevents medial to lateral motion of the fixator. It can also be accomplished by compressing the top 2 pins & bottom 2 pins together (toward each other) while tightening the fixation clamps
• - Application limited to the bones below the stifle & elbow, primarily tibia & radius

Modified Type II:

• - As it can be difficult to get all 4 fixation pins in the same plane on either side of the bone, many surgeon's modify the type II by only using one full pin in each segment with additional half pins for adequate stability.
• - Same plane of pin insertion on either side of the bone can be achieved by using a pin guide or 2 connecting bars on one side

5.23.8 COMPLICATION OF K-E APPARATUS

• i) Pin tract sequestra: Generally due to thermal necrosis if present should be removed
• ii) Local Infections of pin tract & drainage: most common problem. Could be caused by
  • - excessive skin & soft tissue movement
  • - tension against the skin
  • - Loosening of the pins

Generally clears up if pin is tightly seated otherwise remove the loose pin

• iii) Loosening of skeletal fixator: pins loosen
  • - due to angle of insertion being less than 35
  • - due to loosening of single fixation clamp
• iv) Bending of the transfixation pins: due to
  • - too much weight bearing
  • - Insufficient pins (few in #)
  • - Inappropriate size
• v) Iatrogenic fractures due to
  • - use of oversized pins
  • - pins placed too close together or near the fracture line (war zone) or in a fissure
  • - Unrestricted activity causing fracture through pin holes

5.23.9 CLIENT EDUCATION:

• - Restrict activity
• - Leash walk
• - Avoid fencing etc which may catch or tangle the apparatus
• - Inspect apparatus daily for any foul smell discharge etc
• - Return every 2 wk s for checkups & evaluation
• - Restricted activity to continue for additional 6-8 wks even following removal of splintage

5.23.10 PIN REMOVAL:

• - Sedation/Anesthesia
• - Disassemble the frame & extra pins by hand or chuck or needle
• - nose vise grip pliers
• - Remember to unscrew if threaded pins were used
• - A small amount of serosanguineous fluid often drains from the pin site.
• - A soft padded bandage may be used for a day or two

5.23.11 INTRAMEDULLARY PINNING

• - It is the most readily used system of Internal fixation
• - Devices used in veterinary medicine are Steinmann pins, K - wire Rush pin & Kuntschner nail. Last 2 are not used very frequently.

5.23.12 STEINMANN PINS & I.M. FIXATION

• - Steinmann pins commonly used are 9" to 12" long and 1/16" to 1/1" in diameter.
• - The pins maybe available in chisel Trocar & Threaded tlocar point.
• - Maybe double pointed or single pointed
• - The chisel Point is less apt to leave the medullary cavity or penetrate out of the opposite cortex
• - A pin-chuck is required for its insertion
• - Due to its round, smooth shape it offers little resistance to rotation
• - Stability can be improved by use of
• - Auxillary fixation like K-E app
• - Or circlage or hemicerclage wires
• - Or multiple pinning (stack pinning)
• - Using a large pin that fills the medullary cavity
• - Placing pin so as it exerts a dynamic force.
• - Healing is due to the development of periosteal bridging callus
• - When K-E apparatus is to be used in conjunction with an I.M. pin the size of IN pin should be about 60-70% of the medullary cavity
• - Should be used in small & medium breeds.
• - Pins can be used with an open or closed approach
• - Used mostly in fractures of long bones i.e. femur, Tibia, Humerus, ulna Radius?
• -- Closed technique used when fracture is of recent origin easily reducible, and stable.

Indications:

• - Diaphyseal Fr of long bones
• - Irregular transverse & short oblique Fr.
• - In spiral & comminuted with auxillary fixation

Advantages:

• - Simple technique
• - Inexpensive
• - Minimal surgical time

Disadvantages:

• - No rotational stability or resistance to compression or traction forces
• - Damage to medullary blood vessels & ostrozenic tissue

5.23.13 TECHNIQUE OF I.M. PINNING

5.23.13.1 Retrograde Technique: (Femur) (Humerus)?

• - Pin is inserted from the fracture site into the medullary canal of the proximal fragment with a steady pressure and back & forth quarter turns of the pin chuck.
• - The pin is advanced up the medullary cavity till it comes out of the trochanteric fossa and out of skin
• - The pin chuck is disengaged and applied to the pin protruding from the skin. The pin is withdrawn slowly, again by making 1/4th turn of the wrist, till its end is level with the distal end (Fracture end) of the proximal segment
• - Fr. is reduced aligned and held in this position
• - Pin chuck is advanced so as to send the pin down the medullary cavity of the distal segment where it is seated in the metaphyseal epiphyseal area.
• - The pin setting is evaluated by measuring with an other pin of same length or by radiography
• - The excess pin, protruding from the skin at trochanteric fossa is cut with pin cutter as close as possible and pushed under the skin
• - Extreme caution is taken to avoid penetration of distal/adjacent joint surface.

5.23.13.2 Antegrade/Normograde/Direct pinning:

• - The pin is directed into the medullary canal of one fragment from the appropriate point on the epiphyseal area up to the fracture line
• - The fracture is reduced and held in reduction while the pin is advance across the fracture line into the other segment and seated securely

Point of Start/Entrance	Bone	Seating of pins
Subtrochanteric fossa	Femur	Distal caudal condyle
Ant crest of greater tubercle	Humerus	Medial condyle
Medial slightly behind straight	Tibia	Medial malleolus
patellar ligament	Ulna	Olecranon process
Distal epiphysis at thecranial border	Radius	(Mostly avoided)

5.23.13.3 Multiple (Stacking) Pins:

• - Provide more secure fixation
• - Pins can be inserted retrograde/normograde
• - Or first pin retrograde & then following reduction additional pins antegrade multiple points or contact provide more rigid fixation against rotational stress
• - However, tendency of pins to migrate
• - Caution against splitting the none when cortex is thin or there are fissures present

Cross Pins: Pins are placed across fracture line at converging angles so as to provide 2 or more points of fixation.

• - Pins should not cross at Fr. line

Indication: Metaphyseal - Epiphyseal Fracture I-IV (Salter)

Advantage: Provides stable reduction without invading joint.

Early joint motion

Disadvantage: - Retard physeal growth?

• - More difficult than direct pinning
• - Pin retrieval difficult

5.23.13.4 Rush pinning

• - Pin when driven into bone provides three point fixation. As in a spring loaded tension
• - Rush pin has a bevel at one end (to slide off the far cortex and glide along inner cortical surface) and a hook on the other (to engage in the cortex)
• - Requires a guide hole to insert the pins
• - Pins come in 3/32", l/8", 3/16" & 1/4" diameter
• - Steinmann wires/pins can be made into or used as rush pins or in rush pin principle
• - 2 pins are inserted into metaphyseal region at an acute angle of 30 to the long axis of bone
• - Pins are hammered alternately slowly in and up the medullary cavity. The beveled end of the pin bounces of the opposite endosteum to engage or rest against the starting cortex. This provides three point fixation.

Indication: Fr. of metaphyseal region Fr. of Proximal humerus & Tibia and distal femur

Disadvantage: Premature closure of physis, if used in young animals?

5.23.14 CLASSIFICATION OF PLATES (per function)

5.2314.1 Compression plate:

used as static Intra frag. compression or dynamic compression (Tension band)

Plate must have sufficient rigidity for the size & weight of the animalShould be applied on the tension side of the bone to achieve dynamic compression

Compression can be achieved by the use of DCP plate, external tension device, semitubular plate

Indications for the use of DCP plate

• - Transverse fracture
• - Short oblique Fr,
• - Osteotomies
• - Arthrodeses
• - Non-unions

Principle:

A DCP plate has oval gliding holes. When are drilled by the use of a loading drill guide, it helps make the holes in the bone towards the top of the bone plate glide holes thereby giving compression of about l mm when screws are tightened.

Application of a 3.5mm DCP to a Tr. Fr.- an example

• - Contour an aluminum template to the surface of the reduced bone
• - Form the 3.5 mm dynamic compression plate according to the shape of the template
• - Over bend the plate in its unperforated middle part so that it will be very slightly raised from the bone
• - Drill the first hole 7-8 mm from the fracture gap, through both cortices using the 2.0/2.5 mm drill bit through a drill guide (load) with eccentrically situated hole and an arrow pointing towards the fracture gap

Measure the depth (length) of the hole (i.e.Width of the bone) by depth gauge

• - Tap both cortices with 3.5 mm tap through a tap sleeve
• - While keeping the Fr. under the plate in reduced position tighten the 3.5 screw through the plate to the bone
• - Similarly tighten the other first screw across the Fr line in the opposite segment
• - This should reduce the Fr gap by 2mm
• - Apply the remaining screws in both segments with a green ventral 3.5 mm drill guide

Green/Neutral drill guide provides 0.1 mm compression for each screw tightened

Retighten all the screws Check again if any motion is seen in any screw Screws are tightened by finger pressure only

5.23.14.2 Neutralization plate:

Splinting of a lag scretw fixation as screws alone provide a very questionable stability to fracture area

Plate neutralizes and transmits weight bearing forces that would set in the fracture area

Indications:

Spiral, oblique & comm. diphyseal Fr.

Application:

Same as in compression plating except the holes are drilled using neutral guide Plate is bent precisely to the contour of the bone. A DCP (or round hole plate) can be used.

C. Buttress Plate:

• - used to shore up a fragment of bone Fr. bridge or splint a Fr. area to maintain leg length

Indications:

• - comminuted diaphyceal fractures
• - Proximal tibia1 plateau Fr.
• - Osteotomies for leg lengthening procedure
• - Some metaaphyseal Fr.
• - Where distraction-support is needed

Application:

Plate fixed to main fragments with primarily the objective of holding them the correct distance apart while reconstructing the bone shape. If DCP is used the screws are seated using 2.0 mm drill sleeve inserted through the plate hole towards the fracture. A11 screws are inserted in buttress position

- Application of screws (the steps involved) is same as with other plating techniques

5.24 BONE PLATES

• - Ideal for accomplishing an early return to full function
• - Different designs, cross-sectional area & hole types plates available
• - It is important to choose a plate of correct length and type. Straight plates & semi-tubular plates are the ones commonly used.
• - AO, ASIF plates (straight) are made to accommodate 20 m.m. 2.7mm, 3.5mm & 4.5mm screws, 4.5 plates can be had in narrow or broadtype (width)
• - Semitubular plates are only one m.m thick; and are used as tension band plates. There rigidity is due to their profile
• - 1/2 circle - used with 4.5 & 6.5 screws 1/3 circle used with 3.5 screws u 4.0 1/4 circle - used with 2.7 screws
• - Round hole plates are used with an external tension device when compression at fracture site is desired
• - Length of the plate should be more or less equal to the length of the bone i.e. continue towards metaphyseal area
• - A minimum of 3 screws should be placed on either side of the fracture
• - The first screws on either side of the fracture should not be less that 5mm from the fracture line. 1 cm would be ideal
• - Correct and accurate contouring of the plate to the bone is necessary. Maybe advantageous to prestress or acutely bend the plate where it is next to the Fr. line so that there is a gap of 1 to 1.5 mm between the plate and the bone. Should be practiced when working on compression of transverse fractures on relatively straight bones
• - Plates are positioned on the tension side of the bone
  • Femur - lateral surface
  • Prox. Tibia - Medial (cranio)
  • Radius - Anteriolateral aspect
  • Humerus - Anterio-lateral aspect
• - Plates when used in dynamic compression fashion result in primary bone healing
• - Center plate over fracture, avoid Fr. line under the plate hole.
• ication of screws (the steps involved) is same as with other plating techniques

5.24 BONE SCREWS

5.24.1 Cortical: -

used primarily in the diaphyseal bone

• - Screws are fully threaded with more threads per unit length than cancellous screws.
• - Threads are shallower & more flat pitched
  • Cancellous: used to compress fragments of epiphyseal & metaphyseal area
• - Maybe partially or completely threaded
• - few threads per unit length
• - Threads are deep & relatively high pitched

Indication:

a) Primary fixation alone in epiphyseal or metaphyseal fractures

• - Cancellous screws; partially threaded are implanted with no threads crossing the fracture line after drilling the appropriate size hole in both segments, tapping it and the seating the appropriate length screw .
• - Some cancellous screws are self tapping
• - Tightening the screw, brings compression of the segments as the near fragment slips on the smooth shank

5.24.2 Intrafragmentary Compression with a cortical screw

• - Insert in a lag fashion or to achieve a lag effect
• - It requires drilling a larger hole (the diameter equal to the size of the screw) in the near cortex and another hole equal to the size of the core of the screw in opposite or far c o r t e x
• - The far cortex is tapped with a corresponding tap, diameter of which is equivalent to the size or the screw to be implanted
• - The tap is always moved 2-3 rotation forward & 1/4 rotation backwards

An appropriate size ( ie . length ) screw is tightened

Steps involved

• i) drill near cortex with a drill bit the size of the screw
• ii) drop drill sleeve through it and drill the far cortex with a drill bit corresponding to the screw core size
• iii) Measure after countersinking
• iv) Tap with the same size tap as the screw size

  TENSION BAND WIRE:

  Principle:

  • - Active distracting forces are counteracted and converted into compressive forces - It is achieved by inserting 2 K- Wires & a tension band orthopedic wire

  Indication: Avulsion fracture or osteotomies of any apophyseal area - Avulsion Fr. of tibial tubercle, medial malleolus, tuberculosis or acromial process of scapula

  • - Arthrodesis of inter tarsal joints
  • Technique for repairing Fr. of Olecranson Process:
  • - Reduce Fr.
  • - Insert two pins from the top of olecranon process starting from its caudomedial/lateral corners across the fracture line to engage the cranial cortex of the ulna distally. Reep pins parallel to each other
  • - A transverse hole is drilled through the diaphysis below the fracture line & an orthopedic wire is passed through it
  • - The wire is twisted in figure eight fashion and tightened by twisting
  • - Individual K-ires are bent backwards, cut & rotated anteriorly so that ends are burried in soft tissue

5.24.3 Cerclage or Hemicerclage wire:

• - Circle of wire that completely or partially goes around the circumference of a bone
• - They are not used as sole method of repair or fixation in any type of fracture

Indications:

• - Long oblique, spiral & comminuted Fr
• - For auxillary fixation
• Technique (General):
• - Use wires of sufficient strength 10, 20,22 gauge
• - apply tightly
• - Used on diaphyseal fractures
• -- Notching may be needed
• - Space them about l cm apart & 0.5 cm from Fr. line
• - Never use less than 2 wires
• - Length of Fr. line should be double the diameter of bone

5.24.4 Application of Cerclage wire:

• - reduce fracture segments
• - pass the wire around both segment with a wire passer or a curved hemostate
• - Be sure not to include any soft tissue between wire & bone
• - Twist wire ends uniformly
• - When it is tight keep tightening & bend it towards bone
• - Cut excess off

5.24.5 Hemicerclage application:

• - Drill a hole on either side of Fr. line
• - Pass a wire through the holes and twist the wire ends together to compress the fracture line
• - Cut excess wire off
• - Can be used around an I.M. Pin