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Tissue Healing and Wound Care

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1 Tissue Healing and Wound Care
Chapter 6

2 Force and Its Effects Two potential effects of force: Acceleration
Deformation Factors that determine injury Magnitude of force Material properties of tissues involved

3 Response to Force Small load - elastic response
Load is removed, material returns to its original shape Load reaching yield point - plastic response Load is removed, some amount of deformation remains Yield load Maximum load a material can handle without permanent deformation Failure Force such as loss of continuity, rupturing soft tissue or fracturing bone

4 Direction of Force Many tissues are anisotropic
Different strengths in response to loads from different directions Anatomic make-up of joint Susceptibility from a given direction

5 Categorize Force Relative to Direction
Axial Force that acts on the long axis of a structure Compression Axial load that produces a crushing or squeezing type force Tension Axial force in opposite direction; pulling or stretching the tissues Shear Force parallel to a plane passing through the object Tends to cause sliding or displacement

6 Categorize Force Relative to Direction (cont.)

7 Magnitude of Stress Stress
Force divided by the area over which the force acts A given force over a large area vs. a small concentrated area can have very different results

8 Strain vs. Force Strain The amount of deformation relative to the original size of the structure Result Compression - shortening and widening Tension - lengthening and narrowing Shear - internal deformation Problem: high strain rather than high force The ability to resist strain relative to strength of tissues

9 Element of Time Acute injury Results from a single force
Causative factor - macrotrauma Characterized by a definitive moment of onset Chronic or stress injury Results from repeated loading Causative factor - microtrauma Characterized by becoming more problematic over time

10 Positive Stress vs. Adverse Stress
gradual mechanical stress size & strength

11 Torque Moment arm Perpendicular distance from force line of action to the axis of rotation Torque Force × moment arm Produces rotation of a body

12 Torque (cont.) Injury potential Bending
Tension on one side of object and compression on the other side Torsion Twisting an object's longitudinal axis

13 Soft Tissue – Anatomic Properties
Collagen Primary constituent of skin, tendon, ligaments Protein substance strong in resisting tensile forces Wavy configuration that allows for an elastic type deformation or stretch but, otherwise, is inelastic Elastin Protein substance Adds elasticity

14 Skin Epidermis Dermis Multidirectional arrangement of collagen

15 Tendons Muscle to bone Dense connective tissue with unidirectional bundles of collagen and some elastin Collagen - parallel arrangement Helps in resisting high, unidirectional tension loads from the attached muscle Two times as strong as muscle it serves Yield point 5-8% in length

16 Aponeuroses Attach muscle to other muscles or bone
Dense connective tissue Strong, flat, sheet-like

17 Muscle Viscoelastic Extensibility - ability to be stretched
Elasticity - ability to return to normal length Viscoelasticity allows muscle to stretch to greater lengths over time in response to a sustained tensile force

18 Muscle (cont.) Irritability - ability to respond to a stimulus
Electrochemical - nerve impulse Mechanical - external blow Contractility - ability to develop tension Isometric Concentric Eccentric

19 Joint Capsule Membrane that encloses a joint; composed primarily of collagen Function: hold bones in place Inner lining: synovial membrane Exit for waste; entrance for nutrients Secretes synovial fluid (lubricates and nourishes)

20 Ligaments Bone to bone Collagen is parallel and interwoven
Resists large tensile loads along the long axis of the ligament and smaller loads from other directions Collagen and elastin intermixed (more elastic than tendons)

21 Bursa Fluid-filled sacs Reduce friction
Common sites – areas of friction

22 Classification of Joints
Fibrous (synarthrosis) Held together by fibrous tissue Can absorb shock but permits little or no movement of the articulating bones Example: sutures in the skull Syndesmoses Joined by dense fibrous tissue Permit extremely limited motion Example: interosseous membrane

23 Classification of Joints (cont.)
Cartilaginous (amphiarthroses) Primary Held together by hyaline cartilage Example: sternocostal joints; epiphyseal plates Can absorb shock, but permits little or no movement Secondary Held together by fibrocartilage Movement of the articulating bones Designed for strength and shock absorption

24 Classification of Joints (cont.)
Synovial (diarthroses) Freely movable joints Classified according to their shape – dictates type and range of motion permitted Plane Hinge Pivot Condyloid Saddle Ball and socket

25 Classification of Joints (cont.)
Synovial joint Articular cartilage Covers ends of long bones, cushion and protection, no nerve or blood supply Joint cavity Filled with synovial fluid

26 Classification of Joints (cont.)
Articular capsule Joint capsule Synovial fluid Reduces friction Ligaments Capsular, extracapsular

27 Skin Injury Classifications
Abrasions Scraping away of layers of skin Blisters Accumulation of fluid between epidermis and dermis Skin bruises Accumulation of blood within skin Incisions Clean cut

28 Skin Injury Classifications (cont.)
Lacerations Irregular tear Avulsions Complete separation of skin Punctures Penetration of skin and underlying tissue

29 Classification of Muscle/ Tendon Injuries
Contusion Mechanism: compression Signs and symptoms (S&S) Onset - acute Pain - localized Ecchymosis: if superficial Restrictions in ROM Swelling Associated nerve compression

30 Contusion (cont.) Basis for rating severity – ROM
1st – little or no restriction 2nd – noticeable reduction 3rd – severe restriction Concern: can lead to muscle strain

31 Strain Stretch or tear of a muscle Mechanism: tension force
Most common site for tears: near the musculotendinous junction Key factor: magnitude of force and structure's cross-sectional area

32 Classification of Strains
2nd 3rd damage to fibers few fibers torn nearly half torn all fibers torn weakness mild moderate (reflex inhibition) severe muscle spasm moderate loss of function severe (reflex inhibition) swelling palpable defect no yes (if early) pain-contraction moderate /severe none/mild pain-stretching yes ROM decreased depends on swelling

33 Cramps and Sprains Involuntary muscle contraction Cramp
Biochemical imbalance, fatigue Types Clonic - alternating contraction/relaxation Tonic - constant Spasm Reflex action due to: Biochemical or Mechanical blow to nerve or muscle

34 Myositis and Fasciitis
Inflammation of connective tissue Fasciitis Inflammation of the fascia surrounding portions of a muscle

35 Tendinitis and Tenosynovitis
Inflammation of tendon Pain and swelling with tendon movement Problems - repeated microtrauma Degenerative changes Tenosynovitis Inflammation of synovial sheath S&S Acute: rapid onset, crepitus, local swelling Chronic: thickened tendon, nodule formation in sheath

36 Myositis Ossificans Ectopic calcification - located in place other than normal Bone (calcium) is deposited within a muscle Usually macrotrauma, but can be microtrauma

37 Chronic Conditions Result of repeated irritation of tissues
Classification Stage 1: pain after activity only Stage 2: pain during activity, does not restrict performance Stage 3: pain during activity, restricts performance Stage 4: chronic unremitting pain, even at rest Problem – low-grade inflammatory condition that results in collagen resorption and scarring

38 Joint Injury Classifications Sprain
Stretch or tear of ligament Mechanism of injury (MOI) – tension force Compromises the ability of the ligament to stabilize the joint

39 Classification of Sprains
1st 2nd 3rd damage to ligament few fibers torn nearly half torn all fibers torn distraction stress <5 mm 5-10 mm >10 mm weakness mild moderate/severe muscle spasm none none/minor loss of function severe swelling moderate pain-contraction pain-stretching yes no ROM decreased increase or decrease

40 Dislocation/Subluxation
Joint force beyond normal limits MOI: tension S&S Loss of limb function Deformity Swelling Point tenderness

41 Dislocation/Subluxation
Problem of reoccurrence Due to overstretching of capsule to the extent that it will not return to normal; unstable joint

42 Bursitis Inflammation of bursa Acute or chronic MOI: compression
S&S: swelling, pain, loss of function, eventual degeneration

43 Osteoarthritis Degeneration of articular cartilage
S&S: pain and limited movement No definitive cause; rather, several contributing factors

44 Soft Tissue Healing Inflammatory phase (0-6 days)
Acute or chronic inflammation possible Exudate forms Mechanisms for stopping blood flow Local vasoconstriction Platelet reaction Coagulation cascade

45 Soft Tissue Healing (cont.)
Vasodilation brings neutrophils and macrophages to clean the area via phagocytosis Mast cells release Heparin: thins the blood and prolongs clotting Histamine: promotes further vasodilation Bradykinin: opens the blood vessel walls; causes pain

46 Soft Tissue Healing (cont.)
Inflammatory phase (cont.) Zone of primary injury Hematoma forms Edema occurs Increased permeability and pressure within the vessels forces a plasma exudate into the interstitial tissue

47 Soft Tissue Healing (cont.)
Zone of secondary injury Interstitial tissues affected by inflammation, edema, and hypoxia Prostaglandins promote further healing and clearing of debris

48 Soft Tissue Healing (cont.)

49 Soft Tissue Healing (cont.)
Proliferative phase (3-42 days) Repair and regeneration of tissue Processes Angiogenesis Fibroplasia Re-epithelialization Wound contraction

50 Soft Tissue Healing (cont.)
Hematoma reduces for new healing to take place Scar formation with soft tissue Accumulated exudate contains fibroblasts that generate new collagen Newly formed blood supply and support of matrix will determine overall healing of new tissue

51 Soft Tissue Healing (cont.)
Maturation phase (3 weeks – 1 year) Associated processes Remodeling of fibrous matrix to form mature scar tissue Decreased fibroblastic activity Increased organization of new tissue Decreased water content Decreased blood flow Resumption of normal cell activity in the area

52 Soft Tissue Healing (cont.)
Scar tissue is fibrous, inelastic, and nonvascular Less functional and flexible than original tissues Tensile strength 3-4 weeks – 25% of normal 4-5 months – 30% below preinjury strength

53 Soft Tissue Healing (cont.)
Maturation phase (cont.) Muscle fibers form adhesions Tendons and ligaments slower to heal Potential for atrophy with immobilization Loss of strength and decreased rates of healing are directly related to length of immobilization Begin strengthening as soon as it’s safe after injury to ensure hypertrophy of healing tissues and decreased reoccurrence of injury

54 Soft Tissue Wound Care Open wound
Follow universal precautions and infection control standards General Apply pressure Cleanse the wound Dress and bandage the wound Use of creams or ointments Re-dress and inspect

55 Soft Tissue Wound Care (cont.)
Closed wound Goal: reduce inflammation, pain, and secondary hypoxia Treatment: ice, compression, and elevation

56 Long Bones – Anatomic Properties
Primary constituents: minerals, collagen, water Components Diaphysis Shaft - hollow, cylindrical Medullary cavity - shock potential improves

57 Long Bones – Anatomic Properties (cont.)
Epiphysis Ends of long bones Epiphyseal plate - cartilaginous disc found near ends of long bones Periosteum Sheath covers bone Life support system

58 Long Bones – Anatomic Properties (cont.)
Bone growth Longitudinal Continues until epiphysis closes Diameter Can continue to grow through the lifespan

59 Long Bones – Anatomic Properties (cont.)
New bone formed via the periosteum; bone is resorbed around the medullary cavity Osteoblasts – form new bone Osteoclasts – resorb bone Bone experiences constant remodeling

60 Internal Composition: Long Bones – Anatomic Properties (cont.)
Cortical Compact bone tissue of high density (low porosity) Outside Can withstand greater stress but less strain Cancellous Bone tissue of low density (high porosity) Inside Can tolerate more strain

61 Long Bones – Anatomic Properties (cont.)
Size will increase in response to increased stress (conditioning) Hollow cylinder - strongest structure in resisting tension and compression Anatomic weakness - site where bone changes shape and direction (especially sudden change)

62 Mechanical Forces Affecting Bones
Tension, compression, shear, bending, torsion Stronger in resisting compression than both tension and shear

63 Classification of Bone Injuries
Fractures Disruption in the continuity of bone Closed or open Type of fracture determined by: Force applied The health and maturity of bone at the time of injury

64 Types of Fractures

65 Stress Fracture Stress fracture
Fracture results from repeated loading with lower magnitude forces Can become worse over time

66 Osteopenia Osteopenia
Reduced bone mineral density that predisposes individual to fracture Possible causes: amenorrhea, hormonal factors, dietary insufficiencies

67 Epiphyseal Injuries Injury to growth plate could result in alteration in normal growth Acute injury Types I-V Osteochondrosis

68 Epiphyseal Injuries (cont.)
Osteochondrosis Disruption of blood supply to epiphysis Idiopathic Example: Legg-Calvé-Perthes disease Apophysitis Osteochondrosis of apophysis Example: Sever’s disease Osgood-Schlatter disease

69 Bony Tissue Healing Acute inflammatory phase Formation of hematoma
Inflammatory response Proliferative phase Osteoclasts – resorb damaged tissue; osteoblasts – deposit new bone Callus formation Maturation phase Continued activity of osteoclasts and osteoblasts Remodeling of bone

70 Bony Tissue Healing (cont.)

71 Bony Tissue Healing (cont.)

72 Bony Tissue Healing (cont.)

73 Bone Injury Management
Fracture detection Palpation, percussion, tuning fork, compression, distraction Management – splinting (refer to Application Strategy 6.3)

74 Nerve – Anatomic Properties
Spinal nerve Roots Posterior – afferent Anterior – efferent Heavily vascularized Myelin sheath

75 Spinal Nerves

76 Classification of Nerve Injuries
Tensile force injuries Neurapraxia (grade 1) Localized conduction block: temporary loss of sensation and/or motor Resolves within days to a few weeks Axonotmesis (grade 2) Significant motor and mild sensory deficits Lasts at least 2 weeks

77 Classification of Nerve Injuries (cont.)
Neurotmesis (grade 3) Motor and sensory deficit Lasts up to 1 year Compressive injuries

78 Classification of Nerve Injuries (cont.)
Nerve injuries result in a variety of afferent symptoms Hyperesthesia Hypoesthesia Paresthesia Neuralgia Chronic pain along nerve’s course Healing: if completely severed, healing does not occur

79 Management of Nerve Injuries
Mild – follow acute care protocol Moderate to severe – physician referral

80 Pain Sources Somatic, visceral, and psychogenic Nociceptors
Mechanosensitive Chemosensitive Fibers transmitting pain A fibers C fibers T cells Gate control theory of pain

81 Pain (cont.) Factors than mediate pain
Brain production of opioid peptides and endorphins Cognitive and affective filters Referred pain Pain perceived at a location remote from the site actually causing the pain Radiating pain Pain felt both at its source and along a nerve


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