1. 2 Concepts of Healing

2. Healing By secondary intention: Separation is large Tissue must fill space More scar, longer healing time By primary intention: Separation is small Bridge of cells binds ends of wound together Minor wounds, suture wounds

3. Tissue Healing Phases

4. Inflammation 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

5. Signs of Inflammation Redness Temperature increase Edema Pain Reduced function

6. 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 Inflammation

7. Proliferation 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

8. Signs of Proliferation Redness Swelling Pain Local temperature

9. Remodeling 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

10. Signs of Remodeling Reduced redness Reduced edema Reduced pain No local temperature

11. Growth Factors Proteins Perform important roles in healing process Specific growth factors impact specific cells Named for target cells, source, behavior

12. Roles of Growth Factors in 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

13. Ligament Healing Site 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.

14. Tendon 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 synthesis Fibroblast proliferation; revascularization; synovial sheath rebuilt

15. Muscle Healing Fragmentation 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 produced Day 7-11: near-normal tensile strength Regenerating myotubes; cross- striated muscle fibers

16. Articular Cartilage Healing Fibrin clot is formed Fibroblasts 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

17. Bone Healing PMNs, plasma, lymphocytes Fibroblasts invade 3-4 months: Fracture is healed Week 12: near-normal strength restored Hematoma forms; fractured edges become necrotic Osteoclasts proliferate; hard callus develops External blood supply dominates; then medullary circulation reestablished

18. 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

19. Tensile Strength During Healing 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)

20. Tensile Strength During Healing Phases Remodeling Bone 83% of normal in 12 weeks Ligament and tendon near normal in 17-50 weeks Full tensile strength never regained

21. 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 Strength

22. Factors That Affect Healing Modalities Medications/Drugs Other modifying factors (age, disease, etc.)

23. Treatment Modalities Ice Electrical stimulation Deep heat Superficial heat

24. Influence of Modalities on Healing Relieve pain, spasm, edema Enhance protein synthesis Promote myofibroblast production Retard atrophy, facilitate muscle activity Improve circulation Enhance collagen and neovascular production

25. half-life: the amount of time it takes for the level of a drug in the bloodstream to decrease by half Factors in Medication Effectiveness 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

26. Effects of NSAIDs on Healing Inhibit prostaglandin production Increase blood clotting time Absorption rate decreased when NSAIDs used with antacids Decrease the effectiveness of other drugs

27. Drugs That Can Delay Healing Antibiotics Antineoplastic drugs Corticosteroids Heparin Nicotine

28. Other Modifying Factors That Can Affect Healing Surgical technique Age Edema Disease Muscle spasm Wound size Infection Nutrition

29. Role of Therapeutic Exercise in Inflammation Phase Control edema and pain Limit tissue stress because of weakness of fibrin plug Avoid strengthening activities

30. Role of Therapeutic Exercise in Proliferation Phase 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.

31. Role of Therapeutic Exercise in Remodeling Phase Progressive increase in tensile strength allows progressive increase in stress. Stress application must coincide with increase in tensile strength.

32. Considerations for Appropriate Course Usual healing sequence and timing Individual’s unique response to the injury and treatment

33. Signs of an Overly Aggressive Program Increased pain, especially postexercise Increased edema, especially if lasts more than 1 day postexercise Diminished function from the previous day’s treatment