Fracture Fixation Internal & External

1. Fracture FixationInternal & External

2. http://health.allrefer.com/health/bone-fracture-repair-fracture-types-1.htmlhttp://health.allrefer.com/health/bone-fracture-repair-fracture-types-1.html Fracture Types

3. Systemic 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 Influencing Healing http://www.orthoteers.co.uk/Nrujp~ij33lm/Orthbonefracheal.htm

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** http://www.orthoteers.co.uk/Nrujp~ij33lm/Orthbonefracheal.htm http://www.ivis.org/special_books/ortho/chapter_03/03mast.asp?Type=IPRP&LA=1

5. http://www.hughston.com/hha/a.fracture.htm 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. http://www.hughston.com/hha/a.fracture.htm 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? • Fracture is stable • Patient preference • No complications (Ex.-infection, burn) • When is fixation necessary? • Fracture is unstable • Quick Mobilization • Occupation • Athletes http://www.defence.gov.au/dpe/dhs/infocentre/publications/journals/NoIDs/ADFHealthApr01/adfhealthapr01_2_1_24-28.pdf

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 • Internal • 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 http://www.defence.gov.au/dpe/dhs/infocentre/publications/journals/NoIDs/ADFHealthApr01/adfhealthapr01_2_1_24-28.pdf

10. Internal Fixation http://www.nlm.nih.gov/medlineplus/ency/imagepages/18023.htm

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 http://www.umm.edu/ency/article/002966.htm

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 • 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 http://www.orthogastonia.com/patient_ed/html_pages/hip/hip_hemiarthrooplasty.html

16. Bilboquet Device http://www.maitrise-orthop.com/corpusmaitri/orthopaedic/100_bilboquet/bilboquet_us.shtml

17. Problems in IF • Infection • Delayed union • Non-union

18. External Fixation http://www.nlm.nih.gov/medlineplus/ency/imagepages/18021.htm

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 • 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 • 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 http://www.ilizarov.org.uk/content.htm

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. http://medweb.bham.ac.uk/http/depts/path/Teaching/FOUNDAT/repair/grantiss.htmlhttp://medweb.bham.ac.uk/http/depts/path/Teaching/FOUNDAT/repair/grantiss.html 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 http://www.healthscout.com/ency/68/677/main.html

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 http://www.vetmed.ufl.edu/sacs/notes/Cross-Healing/page9.htmlhttp://wberesford.hsc.wvu.edu/histolch6.htm http://www.nuigalway.ie/anatomy/wilkins/practicals/bone/html/bone_1.html http://www.bm.technion.ac.il/courses/336529/web/Cartilage/major%20types.htm

40. Inflammation & Hematoma http://www.ivis.org/special_books/ortho/chapter_03/03F2.jpg

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 http://www.aans.org/education/journal/neurosurgical/apr01/10-4-1.pdf 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 http://www.healthscout.com/ency/68/677/main.html

43. Callus Formation http://www.ivis.org/special_books/ortho/chapter_03/03mast.asp?Type=IPRP&LA=1

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 http://www.orthoteers.co.uk/Nrujp~ij33lm/Orthbonefracheal.htm 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 http://www.glaciermedicaled.com/bone/bonesc3p2.html 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 http://www.grossmont.edu/shina.alagia/lectures/144/Bone%20physiology.ppt http://www.ecmjournal.org/journal/supplements/vol005supp02/pdf/vol005supp02a07.pdf