2 concepts of healing. healing by secondary intention: separation is large tissue must fill space...
TRANSCRIPT
HealingHealing
By secondary intention:
Separation is largeTissue must fill spaceMore scar, longer healing time
By primary intention:
Separation is smallBridge of cells binds ends of wound together
Minor wounds, suture wounds
Inflammation PhaseInflammation Phase
Occurs during first 3-5 days
Complex cellular and chemical interactions take place
Macrohages replace PMNs in 24-48 h to debride area
Neutrophils abound
The signs of inflammation occur because of the increased metabolic activity and fluid in the region and the tissue damage that has occurred. Loss of function is produced by the primary signs of inflammation.
Causes of InflammationCauses of Inflammation
Proliferation PhaseProliferation Phase
Duration: 2-4 weeks
Angiogenesis and granulation tissue formation
Increased fibroblasts by day 3-5 following injury; reduced PMNs
By day 12, type I collagen replacing type III
Type III collagen formed
Remodeling PhaseRemodeling Phase
Lasts 6-18 months
Myofibroblasts cause wound contraction to minimize scar
Tensile strength increases
Collagen transition—type I replaces type III
Capillaries diminish in number
Signs of RemodelingSigns of Remodeling
Reduced redness
Reduced edema
Reduced pain
No local temperature
Growth FactorsGrowth Factors
Proteins
Perform important roles in healing process
Specific growth factors impact specific cells
Named for target cells, source, behavior
Roles of Growth Factors Roles of Growth Factors in Healingin Healing
Control migration and proliferation of cells
Affect fibrin-plug formation
Stimulate type III collagen degradation, type I synthesis
Control phagocytization
Assist capillary endothelial production
Ligament HealingLigament HealingSite fills with erythrocytes, leukocytes, lymphocytes.
Monocytes and macrophages infiltrate.
Near-normal tensile strength is restored at week 40-50.
Fibroblasts appear, increase, produce extracellular matrix.
Cellular and matrix structures replace the blood clot.Macrophages, fibroblasts diminish; type I collagen replaces type III.
Tendon HealingTendon Healing
Wound gap filled by phagocytes
Fibroblasts revert to tenocytes; type III collagen replaced with type I
Strength is 85-95% normal at week 40-50
Collagen synthesisFibroblast proliferation; revascularization; synovial sheath rebuilt
Muscle HealingMuscle HealingFragmentation of muscle fibers; macrophages appear
Appearance of fibroblasts; reduced muscle tension; phagocytes
Contraction ability: 90% normal at 6 weeks to 6 months
Day 7: scar tissue; near-normal muscle tension can be producedDay 7-11: near-normal tensile strength
Regenerating myotubes; cross-striated muscle fibers
Articular Cartilage HealingArticular Cartilage Healing
Fibrin clot is formedFibroblasts combine with collagen fibers to replace clot
1 month—Fibroblasts differentiate; chondrocytes appear
6 months—type I and II calcified cartilage with normal appearance
2 months—defect resembles cartilage, but collagen is type I
Bone HealingBone HealingPMNs, plasma, lymphocytes
Fibroblasts invade
3-4 months: Fracture is healedWeek 12: near-normal strength restored
Hematoma forms; fractured edges become necroticOsteoclasts proliferate; hard callus developsExternal blood supply dominates; then medullary circulation reestablished
tensile strength: maximal amount of stress or force that a structure is able to withstand before tissue failure occurs—in this case, the amount of outside force that can be applied to a muscle, tendon, ligament, or bone before it tears or breaks
Tensile Strength During Tensile Strength During Healing PhasesHealing Phases
Inflammation
Rapid decline to 50%Source of tensile strength: fibrin clot
Source of tensile strength: collagen, granulation tissue, ground substance
Proliferation
Increase in tensile strength
(continued)
Tensile Strength During Tensile Strength During Healing PhasesHealing Phases
Remodeling
Bone 83% of normal in 12 weeksLigament and tendon near normal in 17-50 weeksFull tensile strength never regained
For a therapeutic exercise program to be successful, one must have respect for the healing process and a knowledge of tensile strength factors.
Healing and Tensile Healing and Tensile StrengthStrength
Factors That Affect Factors That Affect HealingHealing
Modalities
Medications/Drugs
Other modifying factors (age, disease, etc.)
Influence of Modalities Influence of Modalities on Healingon Healing
Relieve pain, spasm, edema
Enhance protein synthesis
Promote myofibroblast production
Retard atrophy, facilitate muscle activity
Improve circulationEnhance collagen and neovascular production
half-life: the amount of time it takes for the level of a drug in the bloodstream to decrease by half
Factors in Medication Factors in Medication EffectivenessEffectiveness
steady state of a drug: the state in which the average level of a drug remains constant in the blood—the amount of drug leaving the body is equal to the amount being absorbed
Effects of NSAIDs Effects of NSAIDs on Healingon Healing
Inhibit prostaglandin production
Increase blood clotting time
Absorption rate decreased when NSAIDs used with antacids
Decrease the effectiveness of other drugs
Drugs That Can Delay Drugs That Can Delay HealingHealing
Antibiotics
Antineoplastic drugs
Corticosteroids
HeparinNicotine
Other Modifying Factors Other Modifying Factors That Can Affect HealingThat Can Affect Healing
Surgical technique
Age
Edema
Disease
Muscle spasm
Wound size
InfectionNutrition
Role of Therapeutic Role of Therapeutic Exercise in Inflammation Exercise in Inflammation PhasePhase
Control edema and pain
Limit tissue stress because of weakness of fibrin plugAvoid strengthening activities
Role of Therapeutic Role of Therapeutic Exercise in Proliferation Exercise in Proliferation PhasePhase
Tissue is weak but improving in strength with collagen production.Patient can start range-of-motion and limited strengthening activities.Exception is in tendon repairs.
Role of Therapeutic Role of Therapeutic Exercise in Remodeling Exercise in Remodeling PhasePhase
Progressive increase in tensile strength allows progressive increase in stress.
Stress application must coincide with increase in tensile strength.
Considerations Considerations for Appropriate Coursefor Appropriate Course
Usual healing sequence and timing
Individual’s unique response to the injury and treatment