Treatment, Rehabilitation and Reconditioning Physiology of Tissue Repair
PHYSIOLOGY OF TISSUE REPAIR Knowing when it is appropriate to begin rehabilitation and when it is acceptable to return to practice and competition require a knowledge and understanding of the healing process. Anatomical Properties of Tissue Two basic elements of tissue: 1. Cells: A mass of protoplasm containing a nucleus 2. Extracellular matrix: Vital, responsive, biochemical, saline gel, containing macro- molecules. ( Two macro-molecules important to skeletal muscle; Collagen, Protoglycans) Collagen: Stiff helical, insoluble protein macro-molecule Proteoglycans: Macro-molecule that acts as an elctro-static sponge
Vascular Supply Tissue Healing If sufficient damage has occurred inflammation is a required step in the activation of wound repair. During the inflammation phase, the body attempts to limit the extent of the injury, to remove devitalized tissue from the wound, and to initiate repairs. Phagocytosis is part of the inflammatory process in which white blood cells ingest dead cells, any foreign material, or infectious agent. The body's reaction to injury in most cases is excessive, causing a disproportionate inflammatory reaction. This inability to finely regulate the inflammatory process may further tissue damage. Repair and regeneration are necessary for the survival of all living organisms. In regeneration, new matrices and cells that are identical in structure and function to those they replace are formed. In repair, new cells and matrices that are not necessarily identical in structure and function to normal tissue replace damaged or lost cells and matrices. The injured tissue is not completely healed and returned to its pre-injured condition until remodeling and maturation has occurred. In addition to a return of pre-injured ROM and strength, this period involves maturation of the newly formed tissue, decreased fibroblast activity, increased organization of the extracellular matrix, and a return to normal histochemical activity. Phases of Healing / Stages of Injury 3 Phases Healing 3 Stages of Injury (Tissue Physiology) (Signs & Symptoms) 1) Acute Vascular Inflammatory Response Acute Stage 2) Repair Regeneration Subacute Stage 3) Remodeling Maturation Chronic Stage
Acute Vascular Inflammatory Response Inflammation: Signs of Inflammation: An acute vasoconstriction lasts a few minutes and is followed by vasodilatation, primarily of pre-capillary arterioles. 1. The initial reaction to trauma is fostered by a complex series of vascular, humoral, and cellular events that are controlled at all stages by chemical mediators. Many of these mediators are produced at the injury site by cells brought to the site as part of the vascular response. Tissue Death, Swelling, Pain, Muscle Spasm Acute Stage (0-4 days) Pain before end of available ROM is reached Inflammation, Pain, Edema, Muscle Spasm Impaired Movement Joint Effusion Decreased use of associated areas
Repair Regeneration 1. Overlaps the acute phase and last 2 days through the next 6-8 weeks. 2. By day 4-5 following the injury, a weak, non-vascular connective tissue (Scar) has been produced over the injury. Because the scar tissue is fibrous, inelastic, and non-vascular, it is weaker and has decrease in function compared to original tissue. Scar formation can reduce the structure's tensile strength by as much as 30% as compared to pre-injury strength. The development of the scar also typically causes the wound to shrink in size, resulting in decreased flexibility of affected tissue. 3. The greater the number of reparative cells, the faster the healing and regeneration. Subacute Stage (4-14/21 days) Pain when end of available ROM is reached Decreasing soft tissue edema Decreasing joint effusion Developing soft tissue, muscle, and/or joint contractures Developing muscle weakness from reduced usage Decreased functional use of part and associated areas Remodeling - Maturation This period involves maturation of the newly formed tissue, decreased fibroblast activity, increased organization of the extracellular matrix, and a return to normal histo-chemical activity. 1. The ability to regenerate & maturate following injury decreases with age. It is also associated with nutrition and general health. Because tendons and ligaments have few reparative cells, healing of these structures can take more than a year. Chronic Stage (14/21 Days - Maturation) Pain when overpressure is applied at the end of ROM Soft tissue, and/or joint contractures or adhesions Muscle weakness Decreased functional usage of the involved part Unable to function normally in described activity