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Muscle Injury , Inflammation & repair

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Introduction to muscle injury , inflammation ,exercise intervention that should be used during each stage during inflammation & repair.

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Muscle Injury , Inflammation & repair

  1. 1. Muscle Injury Inflammation Repair Tahir Ramzan Riphah International University
  2. 2. Introduction--- Types of injuries • Primary Injury – Injury from acute or chronic trauma • Secondary Injury – Inflammatory response to primary injury
  3. 3. 3 Phases of Tissue Healing • Inflammatory –response phase • Fibroblastic-repair phase • Maturation-remodeling phase – Healing process is a continuum and phases overlap one another with no definitive beginning or end points
  4. 4. Inflammatory-Response Phase • After injury, healing process begins immediately – Destruction of tissue produces direct injury to cells of various soft tissue – Characterized by redness, swelling, tenderness and increased temperature – Critical to entire healing process
  5. 5. Inflammatory-Response Phase • Leukocytes and other phagocytic cells delivered to injured tissue – Dispose of injury by-products through phagocytosis
  6. 6. Inflammatory-Response Phase • Vascular reaction – Blood coagulation and growth of fibrous tissue occurs – First 5-10 minutes vasoconstriction occurs • Best time to evaluate • Followed by vasodilation • Effusion of blood and plasma last 24 • Chemical mediators – Released from damaged tissue, white blood cells and plasma – Histamine, leukotrienes and cytokines assist in limiting exudate/swelling – Amt of swelling directly related to extent of vessel damage
  7. 7. Inflammatory Response Con’t • Formation of Clot – Platelets adhere to collagen fibers and create sticky matrix • Platelets and leukocytes adhere to matrix to form plug • Clot formation occurs 12 hours after injury and is complete w/in 48 hrs • Set stage for fibroblastic phase • Chronic inflammation – Acute phase dos not respond sufficiently to eliminate injury agent and restore tissue to normal physiologic state – Damage occurs to connective tissue and prolongs healing and repair process – Response to overuse and overload
  8. 8. Inflammatory Response Con’t • Entire phase last 2-4 days – Greater tissue damage longer inflammatory phase – NSAIDS may inhibit inflammatory response thus delaying healing process • Will assist with pain and swelling
  9. 9. Fibroblastic-Repair Phase • Proliferative and regenerative activity leads to scar formation – Begins w/in 1st few hours after injury and can last as long as 4-6 weeks – Signs and Symptoms of inflammatory phase subside – Increased O2 and blood flow deliver nutrients essential for tissue regeneration
  10. 10. Fibroblastic-Repair Phase • Break down of fibrin clot forms connective tissue called granulation tissue – Consist of fibroblast, collagen and capillaries • Fills gap during healing process – Unorganized tissue/fibers form scar • Fibroblast synthesize extracellular matrix consisting of protein fibers (Collagen and Elastin) – Day 6 –7 collagen fibers are formed throughout scar – Increase in tensile strength increases with rate of collagen synthesis
  11. 11. Fibroblastic-Repair Phase • Importance of Collagen – Major structural protein that forms strong, flexible inelastic structure – Type I, II & III • Type I found more in fibroblastic repair phase • Holds connective tissue together and enables tissue to resist mechanical forces and deformation – Direction of orientation of collagen fibers is along lines of tensile strength
  12. 12. Fibroblastic-Repair Phase • Importance of Collagen – Mechanical properties • Elasticity – Capability to recover normal length after elongation • Viscoelasticity – Allows slow return to normal length and shape after deformation • Plasticity – Allows permanent change and deformation
  13. 13. Maturation-Remodeling Phase • Long term process that involves realignment of collagen fibers that make up scar – Increased stress and strain causes collagen fibers to realign to position of maximum efficiency • Parallel to lines of tension • Gradually assumes normal appearance and function • Usually after 3 weeks a firm, contracted, nonvascular scar exist – Total maturation phase may take years to be totally complete
  14. 14. Maturation-Remodeling Phase • Wolf’s law – Bone and soft tissue will respond to physical demands placed on them • Remodel or realign along lines of tensile force • Critical that injured structures are exposed to progressively increasing loads throughout rehab process – As remodeling phase begins aggressive active range of motion and strengthening – Use pain and tissue response as a guide to progression
  15. 15. Maturation-Remodeling Phase • Controlled mobilization vs. immobilization – Animal studies show Controlled mob. Superior to Immobilization for scar formation • However, some injuries may require brief period of immob. During inflammatory phase to facilitate healing process
  16. 16. Factors that impede healing • Extent of injury – Microtears vs. macrotears • Edema – Increased pressure causes separation of tissue, inhibits neuro-muscular control, impedes nutrition, neurological changes • Hemorrhage – Bleeding causes same neg. effect as edema • Poor vascular supply – Tissues with poor vascular supply heal at a slower rate – Failure to deliver phagocytic cells and fibroblasts for scar formation
  17. 17. Factors that impede healing • Separation of tissue – How tissue is torn will effect healing • Smooth vs. jagged • Traction on torn tissue, separating 2 ends – Ischemia from spasm spasm • Atrophy • Corticosteroids – In early stages shown to inhibit healing • Keloids or hypertrophic scars • Infection • Health, Age and nutrition
  18. 18. Healing Process-Ligament Sprains • Tough, relatively inelastic band of tissue that connects bone to bone – Stability to joint – Provide control of one articulating bone to another during movement – Provide proprioceptive input or sense of joint position through mechanoreceptors • 3 Grades of lig. tears
  19. 19. Healing Process-Ligament Sprains • Physiology – Inflammatory phase-loss of blood from damaged vessels and attraction of inflammatory cells – During next 6 weeks-vascular proliferation with new capillary growth and fibroblastic activity • Immediately to 72 hours – If extraarticular bleeding in subcutaneous space – If intraarticular bleeping occurs in inside joint capsule
  20. 20. Healing Process-Ligament Sprains • Essential that 2 ends of ligament be reconnected by bridging of clot – Collagen fibers initially random woven pattern with little organization – Failure to produce enough scar and of ligament to reconnect 2 reasons ligaments fail • Maturation – May take 12 months to complete – Realignment/remodeling in response to stress and strains placed on it
  21. 21. Healing Process-Ligament Sprains • Factors that effect healing – Surgery or non surgical approach • Surgery of extraarticular ligaments stronger at first but may not last over time • Non surgical will heal through fibrous scarring , but may also have some instability – Immobilization • Long periods of immobilization may decrease tensile strength weakening of insertion at bone • Minimize immobilization time • Surrounding muscle and tendon will provide stability through strengthening and increased muscle tension
  22. 22. Healing Process-Cartilage • Cartilage – Rigid connective tissue that provides support • Hyaline cartilage: articulating surface of bone • Fibro cartilage: interverterbral disk and menisci. Withstands a great deal of pressure • Elastic cartilage: more flexible than other typesauricle of ear and larynx
  23. 23. Healing Process-Cartilage • Physiology of healing – Relatively limited healing capacity • Dependant on damage to cartilage alone or subchondral bone. • Articular cartilage fails to elicit clot formation or cellular response • Subchondral bone can formulate granulation tissue and normal collagen can form
  24. 24. Healing Process-Cartilage • Articular cartilage repair – Patients own cartilage can be harvested and implanted into damages tissue to help form new cartilage – Promise for long term results • Fibrocartilage/Menisci – Depends on where damage occurs – 3 zones of various vascularity • Greater that blood supply better chance of healing on own
  25. 25. Healing Process-Bone • Similar to soft tissue healing, however regeneration capabilities somewhat limited – Bone has additional forces such as torsion, bending and compression not just tensile force – After 1 week fibroblast lay down fibrous collagen – Chondroblast cells lay down fibrocartilage creating callus – At first soft and firm, but becomes more firm and rubbery – Osteoblast proliferate and enter the callus • Form cancellous bone and callus crystallizes into bone
  26. 26. Healing Process-Bone • Osteoclasts reabsorb bone fragments and clean up debris – Process continues as osteoblast lay down new bone and osteoclasts remove and break down new bone • Follow Wolfs law-forces placed on callus-changes size, shape and structure • Immobilization longer 3 to 8 weeks depending on the bone
  27. 27. Healing Process-Muscle • Similar to other soft tissue discussed – Hemorrhage and edema followed by phagocytosis to clean up debris – Myoblastic cells from in the area and regenerate new myofibrils – Active contraction critical to regaining normal tensile strength according to Wolff's Law – Healing time lengthy-Longer than ligament healing • Return to soon will lead to re-injury and become very problematic • 6-8 weeks?
  28. 28. Healing Process-Tendon • Not as vascular as muscle – Can cause problems in healing – Fibrous union required to provide extensibility and flexibility • Abundance of collagen needed to achieve good tensile strength • Collagen synthesis can become excessive can result in fibrosis: adhesions from in surrounding structures – Interfere with gliding and smooth movement – Tensile strength not sufficient to permit strong pull for 4 to 5 weeks » At risk of strong contraction pulling tendons ends apart
  29. 29. Healing Process-Nerve • Nerve cell is specialized and cannot regenerate once nerve cell dies – Injured peripheral nerve- nerve fiber can regenerate if injury does not affect cell body – Regeneration is very slow 3-4 mm /day • Axon regeneration obstructed by scar formation • Damaged nerve within CNS regenerate poorly compared to peripheral nervous system – Lack connective tissue sheath and nerve cells fail to proliferate
  30. 30. Rehabilitation philosophy • Choose therapeutic exercises/modalities that facilitate healing process at specific phases – Stimulate structural function and integrity of injured part – Positive influence on the inflammation and repair process to expedite recovery of function – Minimize early effects of inflammatory process including pain, edema control, and reduction of muscle spasm. • Produce loss of joint motion and contracture – Finally concentrate on preventing reoccurrence of injury by assuring structural stability of injured tissue • Appropriate return to play guidelines

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