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Fracture Fixation Internal & External

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Presentation on theme: "Fracture Fixation Internal & External"— Presentation transcript:

1 Fracture Fixation Internal & External

2 Fracture Types

3 Influencing Healing Systemic Factors Local Factors Age Hormones
Functional activity Nerve function Nutrition Drugs (NSAID) Local Factors Energy of trauma Degree of bone loss Vascular injury Infection Type of bone fractured Degree of immobilization Pathological condition

4 Stages of Fracture Healing
Inflammation & Hematoma Osteoprogenitor cells, Fibroblasts Callus Formation Periosteal and Endosteal Fibro-cartilage differentiation Woven Bone Substitution of avascular and necrotic tissue Haversian remodeling Remodeling Lamellar or trabecular bone Restoration of continuity and ossification Bone union **When compression is applied via implant, these stages are minimized**

5 Healing Complications
Most often due to severe injury Energy dissipation to bone and soft tissue results in damage to blood supply Compartment syndrome Severe swelling resulting in decreased blood supply can cause the muscles around the fracture to die Bad osmotic pressure lets blood out instead of across damaged muscle As pressure remains high, blood cannot get to damaged muscle Neurovascular injury Arteries and nerves around the injury site are damaged Infection Imbalance of bacteria and body’s ability to cope with it when amount of necrotic tissue and contraction of bacteria are not being cleared (by surgeon or patient)

6 Healing Complications (Cont’d)
Delayed union Extended healing time Nonunion Failure to heal Malunion Abnormal alignment Post-traumatic arthritis Fractures that extend into the joints can cause premature arthritis of a joint Growth abnormalities A fracture through an open physis, or growth plate, could result in premature partial or complete closure of the physis; Part or all of a bone will stop growing unnaturally early

7 Treatment When will a cast suffice? When is fixation necessary?
Fracture is stable Patient preference No complications (Ex.-infection, burn) When is fixation necessary? Fracture is unstable Quick Mobilization Occupation Athletes

8 Principles of fracture fixation
Obtain and maintain alignment Reduction Transmission of compressive forces Minimum motion across fracture site Achieve stability Avoid tensile/ shear/torsion forces Across fracture site Prevent motion in most crucial plane

9 Fixation: Internal vs. External
Plates, screws, etc. completely within the body Less expensive Types Comminuted – nail with interlocking screw Transverse or Oblique –plates or screws External Pins coming through skin interconnected by external frame Has complications

10 Internal Fixation

11 Internal Fixation Priciples
Rigid, anatomic fixation Allows an early return to function Reserved for those cases that cannot be reduced and immobilized by external means Open reduction of a fracture Good blood supply to undisturbed tissues

12 Physiological Response to IF
Primary healing Minimal extramedullary callus Minimal intra-medullary callus Sub-periosteal Rapid Related to motion Crosses miniature gaps Depends on soft tissue viability

13 Stress Concentrations
Geometric discontinuities (hole, base of threaded screw, corner) Local disturbance in stress pattern High stresses at site of discontinuity Drilling a hole reduces the bone strength by 10 – 40 %

14 Types of IF Devices Lag screws Kirschner wire Wire loop Plate
Tension band wiring Combination of wire loop and screw Combination of Kirschner and wire loop Plate Intramedullary rods and nails Interlocking screws

15 Hemi-Arthroplasty In the hip, used for femoral neck fractures
Avascular necrosis Fractures of the proximal humerus Early mobilization is facilitated

16 Bilboquet Device

17 Problems in IF Infection Delayed union Non-union

18 External Fixation

19 External Fixation Method of immobilizing fractures
Employing percutaneous pins in bone attached to Rigid external metal Plastic frame For treatment of open and infected fractures

20 Indications for EF Open grade III fractures Gunshot wounds
Compound tibia fractures Generally from motorcycle injuries Gunshot wounds Major thermal injuries Open fractures associated with polytrauma Management of infected nonunions

21 Forces in an External Fixator
Compression Neutralization Distraction Angulation Rotation Translation or displacement

22 Compression For transverse fractures Adds stability at nonunion site

23 Neutralization For comminuted fracture
Compression may lead to excessive shortening Used to maintain: Length Alignment Stability

24 Distraction For distal metaphyseal or intra-articular injuries
Same principle of traction Distraction of fragments Alignment of injury

25 Angulation A – unacceptable alignment B – loosening clamps; loss of distr. and compr. force C – after frames completely loosened; angulation is corrected D - compression on distraction forces are reapplied

26 Rotation Exert rotational force Release of forces first
Along longitudinal axis Release of forces first Can be done with repositioning pins Most of present frames cannot apply rotational forces

27 Translation or Displacement
Volkov apparatus Double ring unit Moves one ring in parallel to other For translation

28 Types of EF Devices Unilateral Bilateral Triangular Quadrilateral
Semicircular & Circular ring Ilizarov

29 Unilateral EF

30 Bilateral EF

31 Triangular EF

32 Quadrilateral EF

33 Semicircular and Circular EF

34 Advantages of EF Easy application Good stability Excellent pain relief
Adjustable Alignment, Angulation, Rotation Access to open wounds Frequent dressing change Monitoring of damaged tissue

35 Disadvantages of EF Application may cause soft tissue damage
Lacks advantages of cyclic loadings as seen in casts Constrained in time Pins may drain Infection

36 The End

37 Granulation Tissue damage repair begins with growth of new capillaries
Red dots are new clusters of capillaries Bleed easily Bright red tissue of a healing burn is granulation tissue

38 Hematoma Blood collection localized to an organ or tissue
Usually clotted Example: Contusions (bruises), black eye, blood collection beneath finger or toenail Almost always present with a fracture

39 Fibrocartilage Cartilage with a fibrous matrix and approaching fibrous connective tissue in structure Produced by fibroblasts Forms in areas where size of the fracture gap is 1mm or greater Subsequently replaced by bone Mechanical properties inferior to other types of cartilage Contains: Large amounts of collagen type I Reduced amounts of proteoglycans Collagen type II, found only in cartilage

40 Inflammation & Hematoma

41 Inflammation & Hematoma
Inflammation begins immediately after a fracture Initially consists of hematoma and fibrin clot Hemorrhage and cell death at location of fracture damage Fibroblasts, mesenchymal cells, osteoprogenitor cells appear next Formation of granulation tissue Ingrowth of vascular tissue Migration of mesenchymal cells Simon, SR. Orthopaedic Basic Science. Ohio: American Academy of Orthopaedic Surgeons; 1994.

42 Inflammation & Hematoma (Cont’d)
Primary nutrient and oxygen supply provided by exposed cancellous bone and muscle Use of anti-inflammatory or cytotoxic medication during first week may alter the inflammatory response and inhibit bone healing

43 Callus Formation

44 Callus Formation Begins when pain and swelling subside
Size inversely dependent on immobilization of fracture Mesenchymal cells form cells which become cartilage, bone, or fibrous tissue Increase in vascularity Ends when bone fragments are immobilized by tissue Stable enough to prevent deformity Callus does not appear on x-ray images Simon, SR. Orthopaedic Basic Science. Ohio: American Academy of Orthopaedic Surgeons; 1994.

45 Mechanical Role Enlarge diameter at fracture site
Reduces mobility Reduces resulting strain Granulation Replaces Hematoma Granulation differentiates into Connective tissue Random orientation of collagen fibrils Their direction reflects the direction of tensile forces Fibrocartilage

46 Deformation of Callus Strength of initial reparative tissue is low
If forces surpass the strength of callus Unstable fracture Functional load deforms fracture Fracture fixation is recommended

47 Woven Bone

48 Woven Bone Callus changes from cartilaginous tissue to woven bone
Callus mineralized but internal architecture is not fully matured/arranged Osteon organization is not complete Connective tissues and fibrocartilage thickens Fracture becomes increasingly stable Mineralization is sensitive to strain Mechanically stable scaffold Increased strength and stiffness with increase of new bone joining fragments Simon, SR. Orthopaedic Basic Science. Ohio: American Academy of Orthopaedic Surgeons; 1994.

49 Bone Remodeling Woven bone becomes lamellar bone
Bone union occurs at fracture gap Callus gradually reabsorbed by osteoclasts Replaced by bone Medullary canal reconstitutes Begins within 12 weeks after injury May last several years Simon, SR. Orthopaedic Basic Science. Ohio: American Academy of Orthopaedic Surgeons; 1994.

50 Mesenchymal Cells Source of cells for new bone production
Derived from bone marrow cells Intramembranous bone formation Formation of bone directly from mesenchymal cells Cells become osteoprogenitor cells then osteoblasts. Development of Cartilage model Mesenchymal cells form a cartilage model of the bone during development

51 Fracture Stability Direction of fracture & material (type of bone) define stability Definition of direction of force important Stable Fissure (Hairline) – not complete break, minimal trauma Greenstick – crack on outside of “bend” Unstable Comminuted – many bone fragments Oblique – break at an angle Spiral – corkscrew-like crack pattern

52 Lag Screw

53 Lag Screw Stability Exerts inter-fragmentary compression
Static compression Distal head must be engaged

54 Screw Holding Force Increase in area of bone within screw threads
Decrease in pilot hole size Increase in length of engaged threaded portion Area available to resist shear

55 Kirschner Wire

56 Kirschner Wire (Cont’d)
Rotational stability May be a problem Anchorage to tension band Twisting of wires on both sides Almost equally distributed compression

57 Tension Band

58 Tension Band (Cont’d) Dynamic compression Used When tension applied
Compressive forces are at the fracture site Used Substitutes torn ligaments & tendons Allows injured ligaments to heal When fragments too small to be screwed

59 Tension band & Screw

60 Tension Band & Screw

61 Plating of Vertebral Column

62 Vertebral Column

63 Intramedullary Pin Types 3-point fixation End fixed in epiphyses Open
Closed 3-point fixation End fixed in epiphyses

64 Intramedullary Pin (Cont’d)
Stability is dependant on Friction / pressure between Deformable nail (elastic recoil) Endosteal surface of medullary canal Fracture “personality”

65 Intramedullary Pin (Cont’d)
Blood supply is from the medullary canal Compromised by intramedullary fixation More care has to be taken

66 Open Fracture Bone ends have penetrated through and outside skin
Important features Polytrauma victims Varying soft tissue damage Contaminated wound Requires emergency treatment

67 Types of Open Fracture Type I – Low Energy Type II
Puncture wound (1 cm dia. or lesser) Not much soft tissue contusion Usually simple transverse, short oblique fracture No crushing component Type II Laceration (more than 1 cm long ) Not extensive soft tissue damage Not severe crushing component Type III – High Energy Extensive damage to soft tissue High velocity injury or severe crushing component

68 Type I

69 Type II

70 Type III

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