The Injury Process of Healing Lecture 8

Soft Tissue everything but bone - 3 phases Involves a complex series of interrelated physical and chemical activities

Inflammatory Phase First event is the actual injury – tissue undergoes some sort of trauma, (can be mechanical, chemical, thermal or infectious agent) Immediate – disruption of tissue – bleeding as a result of vascular structures – namely the capillaries – fluids from damages cells may leak out to the interstitial space (space between the cells) The body responds with vasoconstriction in an attempt to decrease the bleeding – this usually lasts a few minutes Followed by vasodilation

Blood vessels are often damaged, as a result there is an increase in blood flow to the interstitial spaces ( space between cells) This results in a hematoma ( or a localized collection of blood) being formed A hematoma can develop quickly because blood flow can increase as much as 10 times.

Five signs of inflammation? Swelling Pain Redness Warmth Loss of function

Swelling

2) Proliferative (Repair) Phase Second stage in the healing process Body is replacing damaged or dead cells with new cells healing - 3 days to 6-8 weeks Repair process can occur in three ways, and often all three are occurring to some degree at the injured site

Resolution Dead cellular material and debris are removed ( process of phagocytosis) In this case the tissue has suffered minimal damage and is left with its original architecture intact Cells grow and return to their pre injured state

Granulation (fibroplasia) Fibroplasia allows the lost tissue to be replaced with fibrous scar produced from granulation tissue The purpose of the scar is to form a bridge between portions of the tissue that became separated or torn ( the larger the gap the larger the scar) Scar tissue often lack the vascularity, neurological feedback and the strength of the original tissue.

Regeneration the replacement of tissue by the same tissue (restoration of destroyed or lost tissue) Dead or damaged cells are replaced by new cells These cells are the same type not scar tissue Factors that effect our ability to regenerate are, age, nutritional status amount of tissue lost and local blood supply

Primary role of therapist during repair phase is to assist the involved structures in gaining strength Collagen fibres must align along the lines of tensile force, and increase in number and size in response to the appropriate stresses, such as movement and weight bearing and strengthening exercises Must be done with out too much stress as to cause re injury Any new inflammation will delay total healing process, as well as returning to full activity

Maturation (remodeling)Phase Third and final stage, this phase can last a year or more, but generally peeks around 8 – 12 weeks This phase is typically not complete before returning to full activity involves maturation of newly formed tissue, decreased fibroblast activity, increased organization of extracellullar matrix and return to normal histochemical activity over lapping tissue repair and remodelling A definitive scar is formed and tensile strength increases in response to applied stresses Blood flow returns to normal

Factors that Impede healing Local infection Embedded foreign objects Inadequate blood supply Corticosteriods Nutritional deficiencies ( vit c, zinc and protein) General well being (health issues / diabetes)

MUSCLE Muscle is quite different from that if ligaments, tendons and joint capsules Muscles have excellent blood supply, this increases the muscle tissue’s capacity for healing If blood vessels torn then healing may not be as good, pooled blood seen as bruising Ability to return to full function is affected by the size of the tear and the subsequent scar formation Scar tissue is non contractile, stiff and can form adhesions, which may limit movement and function in an otherwise healthy muscle.

Nerves Nerves are thought to heal more slowly than all other tissues When a nerve becomes torn, edges must physically touch for healing to occur If gap becomes filled with scar tissue, the electrical impulses cannot be transmitted, and the scar is permanent road block If healing is successful it is slow because of the poor blood supply