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Bone-Healing Powered By Docstoc
					                                                                                                                                  | Medicine
Bone Healing

Anatomy                                                                        Components of Bone
                                                                                       Cellular                                   Matrix
                                                                               Osteoblast                       Organic (40%)                Inorganic (60%)
                                                                               Osteoclast                 Collagen                       Calcium
                                                                               Osteocytes                 Proteoglycan                   Hydroxyappetite CaPO
                                                                               Osteoprogenitor cells      Matrix Protein
                                                                                                          Growth Factors

                                                                               Requirements of Good Bone Healing
                                                                               Adequate Blood Supply
                                                                               Bone-to-Bone Contact
                                                                               Stability of Fracture Site

                                                                               Factors Influencing Good Fracture Healing
                                                                                              General                                  Local
                                                                               Young                                   Blood Supply, Simple Fractures
                                                                               Good Nutrition                          Immobilisation
                                                                               Non-Smoker                              No Infection
                                                                               No medical Problems

                                                                               Problems in Bone Healing
                                                                                              General                                  Local
                                                                               Smoking                                  Infection
                                                                               Drugs (Steroids)                         Moving too Early
                                                                               Old Age                                  Inadequate Immobilization
                                                                               Shattered Fractures                      Inadequate Apposition
                                                                               Medical Problems                         Bone Loss
                                                                               Poor Blood Supply

                                                                               Other Factors Affecting Bone Healing
                                                                               Anti-Inflammatory, Cytotoxic Medications
Types of Bone
                                                                               Early Inflammatory Stage
                            Lamellar                         Woven             Nicotine
                                                                               Vascularization of Tissue
Subtypes             Cortical     Cancellous      Immature       Pathologic
                                                                               Overall Healing
Characteristics   Structure is   ↑ Elastic       Not Stress     Random
                                                                               Radiation, Systemic Illnesses
                  oriented       than Cortical   Oriented       Organization
                                                                               (Diabetes Mellitus, Rheumatoid Arthritis, Osteoporosis)
                  along lines    Bone                           ↑ Turnover     Inhibitors of Success ful Bone Healing
                  of stress                                     Weak           Advanced Age (Limit Individual’s Healing Potential)
                  Strong                                        Flexible       Rate of Bone Los s
Examples          Femoral        Distal          Embryonic      Osteogenic     •     Before Menopause – 0.3 – 0.5%
                  Shaft          Femoral         Skeleton       Sarcoma        •     After Menopause – 2 – 3 %
                                 Metaphysis      Fracture       Fibrous        Number of Bone Marrow Stem Cells
                                                 Callus         Dysplasia      •     Infant – 1 stem cell / 10,000 marrow cells
                                                                               •     Elderly – 1 stem cell / 2 million marrow cells

                                                                               Assistance in Fracture Healing
                                                                               Correctly Straighten, Immobilize Fractured Bones
                                                                               Cast (POP)
                                                                               Surgery (Inserting Metal Rods, Plates)
                                                                                                                                    | Medicine

Phases of Bone Heali ng
                           Reactive Phase                                                   Reparative Phase                               Remodelling Phase
     Fracture, Inflammatory         Granulation Tissue Formation          Callus Formation               Lamellar Bone Deposition             Remodelling
1st 2 weeks Post-Injury                                            Continued Vascular Ingrowth                                      Months → Years
Initiated after Hemorrhage                                         Secretion of Osteoid                                             (Facilitated by
Subsequent Hematoma                                                Presence of Fibrocollagenous Fibers                              Mechanical Stress)
Infiltration to area, bone (mediated by Prostaglandin)             Temporary Callus is formed (consisting of cartilage)             Restoring to Normal
• Inflammatory cells                                               • Initial Union (1st 4-6 weeks)                                   • Size
   o Macrophages                                                   • Limited Strength                                                • Shape
   o Monocytes                                                     Immobilization of Fracture site is appropriate                    • Strength
   o Lymphocytes                                                   Osteoblasts active                                               Adequate strength usually
   o Polymorphonu clear cells                                      • Replace cartilage with cancellous bone                         develops by 6 months
Fibroblasts                                                        • Form a bridge between Fractured Fragments
Ingrowth of Vascular Tissue
Migration of Mesenchymal Cells

                                                                   Reparative                        Late Reparative
                                                                   Fibrosis                          Hard Callus Formation
                                                                   Woven Bone Production             Reactive Cartilage
Early Inflammatory                                                 Irregular Trabeculae of           (Pale Blue Matrix)
Organizing Hematoma                                                Immature Bone                     Endochondrial Ossification
Ingrowth of Inflammatory Cells, Fibroblasts, Small Blood Vessels   Osteoid rimmed by Osteoblasts     (Eosinophilic Matrix)
Blood Clot

Bone Healing

                                Bone Remodelling

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