Connect iss Lecture 8


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Connect iss Lecture 8

  1. 1. Changes In Tissue During Injury, Immobilization,and Remobilization
  2. 2. Part I: Review <ul><li>Identify Normal Connective Tissue </li></ul><ul><li>Components of Normal Connective Tissue </li></ul><ul><li>Collagen and Elastin </li></ul><ul><li>Proteoglycans & Water </li></ul><ul><li>Fibroblasts and Chondrocytes </li></ul><ul><li>Soft Tissue Changes Following Injury </li></ul>
  3. 3. Normal Connective Tissue <ul><li>Characterized by intercellular material </li></ul><ul><ul><li>Glycoprotein fibers </li></ul></ul><ul><ul><li>Protein polysaccharide ground substances </li></ul></ul><ul><ul><li>Other cells </li></ul></ul><ul><li>Functions </li></ul><ul><ul><li>Provide nourishment for overlying epithelial tissue </li></ul></ul><ul><ul><li>Link muscle & bone as tendons </li></ul></ul><ul><ul><li>Allow movement </li></ul></ul>
  4. 4. Categories of Connective Tissue <ul><li>Loose Connective </li></ul><ul><ul><li>Areolar: most abundant in the body </li></ul></ul><ul><ul><li>Adipose: fat (in the body, not the head) </li></ul></ul><ul><ul><li>Reticular: framework of branching fibers; found in lymph, bone & liver </li></ul></ul><ul><li>Dense Connective </li></ul><ul><ul><li>Collagenous & elastic fibers </li></ul></ul><ul><ul><li>Tendons , ligaments & skin </li></ul></ul>
  5. 5. Components of Normal Connective Tissue <ul><li>Extracellular Components </li></ul><ul><ul><li>Collagen, Elastin, Reticular fibers </li></ul></ul><ul><ul><li>Provide the matrix of connective tissue </li></ul></ul><ul><ul><li>Water & Glycosaminoglycans (GAG) </li></ul></ul><ul><ul><li>Provide lubrication & spacing between collagen fibers </li></ul></ul>
  6. 6. Components of Normal Connective Tissue <ul><li>Cellular Components </li></ul><ul><ul><li>Fibroblasts & Chondrocytes </li></ul></ul><ul><ul><ul><li>Provide material for the matrix </li></ul></ul></ul>
  7. 8. Clinical Implications For Understanding Collagen Tissue <ul><li>In mature collagen the intermolecular cross-linking is strong. </li></ul><ul><li>In newly formed collagen the cross links are weak and can easily be pried apart. </li></ul><ul><li>Avoid excessive force with mobilization in the early healing stages. </li></ul><ul><ul><li>Tendency to damage cross links: can cause mechanical weakness of the tissue . </li></ul></ul>
  8. 9. Collagen Fiber Arrangement <ul><li>Tendons: parallel </li></ul><ul><ul><li>Provide stiffness & strength with a unidirectional load </li></ul></ul><ul><li>Ligaments: Looser, different directions </li></ul><ul><ul><li>Multidirectional </li></ul></ul><ul><li>Skin: random arrangement </li></ul><ul><ul><li>Stretching </li></ul></ul>
  9. 10. Proteoglycans & Water <ul><li>Form ground substance </li></ul><ul><li>Gel like: provide spacing & lubrication between collagen microfibrils </li></ul><ul><li>Hydrophilic: draws water into tissue </li></ul><ul><li>Water is necessary for diffusion of molecules through tissue (exportation of metabolites) </li></ul><ul><li>The spacing, along w/ water, prevents adjacent fibers from linking, thereby reducing friction. </li></ul>
  10. 11. Fibroblasts & Chondrocytes <ul><li>Cellular components of C/T </li></ul><ul><li>Building blocks </li></ul><ul><li>Fibroblasts </li></ul><ul><ul><li>Found in ligaments, tendons, fascia, joint capsules. </li></ul></ul><ul><li>Chondrocytes </li></ul><ul><ul><li>Found in the collagen matrix of articular cartilage. </li></ul></ul>
  11. 12. Soft Tissues Changes Following Injury <ul><li>Two types of cellular events take place in order to repair tissue: </li></ul><ul><ul><li>Immunological </li></ul></ul><ul><ul><li>Reparative </li></ul></ul>
  12. 13. Immunological <ul><li>Immediate </li></ul><ul><li>Prevents bacteria from entering injured area. </li></ul><ul><li>Macrophages & leukocytes </li></ul>
  13. 14. Soft Tissues Changes Following Injury <ul><li>Reparative </li></ul><ul><ul><li>Initiated about 48 hours after injury. </li></ul></ul><ul><ul><li>Collagen initially held by blood clots begins to form a weak mesh. </li></ul></ul><ul><ul><li>During this period adhesions of collagen have little mechanical strength. </li></ul></ul><ul><ul><li>Collagen deposition </li></ul></ul><ul><ul><ul><li>Increases 5th day </li></ul></ul></ul><ul><ul><ul><li>Peaks 14th day </li></ul></ul></ul><ul><ul><ul><li>120 days: reduction of collagen turn over </li></ul></ul></ul>
  14. 15. Changes With Immobilization <ul><li>Research has shown adverse effects with prolonged immobilization. </li></ul><ul><li>Changes take place from cellular matrix to gross tissue levels. </li></ul><ul><li>Areas affected: </li></ul><ul><ul><li>Collagen matrix </li></ul></ul><ul><ul><li>Ligaments/tendons </li></ul></ul><ul><ul><li>Muscle </li></ul></ul><ul><ul><li>Periarticular & intraarticular tissues </li></ul></ul>
  15. 16. Effects of Immobilization on Collagen Matrix <ul><li>Increase in production of collagen </li></ul><ul><ul><li>Deposits in random fashion, not along the lines of stress. </li></ul></ul><ul><li>Decrease in GAG & H2O </li></ul><ul><ul><li>Causes a loss of lubrication and a closer contact of fibers </li></ul></ul><ul><ul><li>Abnormal cross-linking </li></ul></ul><ul><li>Restricted normal interfibril gliding </li></ul>
  16. 17. Immobilization On Ligaments & Tendons <ul><li>Ligaments </li></ul><ul><ul><li>Loss of strength/ stiffness at the insertion point. </li></ul></ul><ul><ul><li>Harwood et al, 1990: atrophy of the ligaments </li></ul></ul><ul><li>Tendon </li></ul><ul><ul><li>Atrophy </li></ul></ul><ul><ul><li>Gelberman 1986: extensive obliteration of space between tendon and sheath </li></ul></ul><ul><ul><ul><li>Adhesions / impediment of glide between sheath & tendon </li></ul></ul></ul>
  17. 18. Effects of Immobilization On Muscle <ul><li>2º shortening of the muscle </li></ul><ul><li>Results in a 40% reduction of sarcomeres (Lederman) </li></ul>
  18. 19. Effects of Immobilization On Periarticular & Intraarticular Structures <ul><li>Atrophy of the capsule, ligaments & synovial membrane </li></ul><ul><li>Adhesions & abnormal cross-links </li></ul><ul><li>Synovial tissue: most sensitive to effects of immobilization, undergoing fibrofatty changes </li></ul><ul><ul><li>Mature fibrofatty tissue will cover non-articulating areas and form adhesions. </li></ul></ul>
  19. 20. Adhesions, Contractions, Cross-Links, Scar Tissue & Contractures <ul><li>Adhesions: “fibrous band holding parts together that are normally separated” </li></ul><ul><li>Form in tendons and sheath, and in the joint capsule. </li></ul><ul><ul><li>Can be stronger than original tissue. </li></ul></ul><ul><ul><li>Watch out when performing aggressive stretching: could avulse normal tissue. </li></ul></ul>
  20. 21. Contraction / Cross-links <ul><li>Contraction: tightening of tissue </li></ul><ul><ul><li>Myofibroblasts pulling together. Eg., Scars </li></ul></ul><ul><ul><li>ROM exercises prevent this. </li></ul></ul><ul><li>Cross-links </li></ul><ul><ul><li>Chemical bonds within & between the collagen molecules. </li></ul></ul><ul><ul><li>Reduce tissue extensibility. </li></ul></ul>
  21. 22. Contractures/ Scars <ul><li>Contractures- </li></ul><ul><ul><li>Indicate loss of movement. </li></ul></ul><ul><ul><li>Shortening of CT & muscle for increased cross linking. </li></ul></ul><ul><ul><li>Reduced by stretching or movement. </li></ul></ul><ul><li>Scar </li></ul><ul><ul><li>Changes in cell & matrix after damage. </li></ul></ul>
  22. 23. Effects Of Mobilization On Tissue <ul><li>Connective tissue matrix </li></ul><ul><ul><li>Turn-over of collagen / remodeling lines of stress. </li></ul></ul><ul><ul><li>Improves GAG synthesis. </li></ul></ul><ul><ul><li>Maintains inter-fibril distance /lubrication. </li></ul></ul><ul><ul><li>Reduces abnormal cross linking. </li></ul></ul>
  23. 24. Effects Of Mobilization On Tissue <ul><li>Joints </li></ul><ul><ul><li>Pressure fluctuations important for formation/removal of synovial fluid. </li></ul></ul><ul><ul><li>Vital to articular cartilage health. </li></ul></ul><ul><li>Ligaments </li></ul><ul><ul><ul><li>Greater strength </li></ul></ul></ul>
  24. 25. Effects Of Mobilization On Tissue <ul><li>Muscle </li></ul><ul><ul><li>Muscle regeneration is dependent on longitudinal mechanical tension provided by passive stretching. </li></ul></ul><ul><ul><li>Research (1966/91) shows the implication of longitudinal mechanical tension in promoting parallel alignment of the myotubules to the lines of stress. </li></ul></ul><ul><li>PROM can improve ROM and increase the cross -sectional area of muscle; also the number & size of sacromeres return to preimmobilization levels. </li></ul>
  25. 26. Effects Of Mobilization On Tissue <ul><li>Tendons </li></ul><ul><ul><li>Higher tensile strength; less likely to rupture. </li></ul></ul><ul><ul><li>Decrease adhesion formation. </li></ul></ul><ul><ul><li>Early mobilization produces a higher DNA and cellular content vs delayed mobilization. </li></ul></ul><ul><ul><li>Revascularization of blood vessels. </li></ul></ul>
  26. 27. Summary <ul><li>Movement provides: </li></ul><ul><ul><li>Direction for the deposition of collagen. </li></ul></ul><ul><ul><li>Vascular regeneration. </li></ul></ul><ul><ul><li>Reduces excessive cross-linking and adhesions. </li></ul></ul>
  27. 28. Considerations <ul><li>Early stages </li></ul><ul><ul><li>Little mechanical strength. </li></ul></ul><ul><ul><li>Avoid aggressive stretching. </li></ul></ul><ul><li>Remodeling phase </li></ul><ul><ul><li>Strong bond. </li></ul></ul><ul><ul><li>Can be more aggressive. </li></ul></ul>
  28. 29. We’d like to thank you for your attention! Please put your chairs in the upright position before exiting the room. Please learn with us again soon!