Injury Mechanisms and Classifications

1. Injury Mechanisms and Classifications Core Concepts in Athletic Training and Therapy Susan Kay Hillman

2. Objectives • Describe the anatomical reference position. • Use appropriate anatomical terminology to describe the location and position of a structure relative to the rest of the body. • Identify characteristics relating to the various stages of physical maturity. • Explain distinctiveness of the various types of musculoskeletal tissue. • Differentiate between elastic and plastic tissue properties. • Classify injuries as either acute or chronic based on the onset and duration of symp­toms. • Define the common chronic inflammatory conditions, including signs and symptoms. • Define the various classifications of closed soft tissue wounds, including degrees of severity. • Define and classify closed and open wounds of the bone and joint articulations. • Classify nerve injuries according to mechanism, severity, and signs and symptoms. • Identify the classifications of open (exposed) wounds.

3. Introduction • Proper reference to anatomical positions, knowledge of injury terminology, and mechanisms essential for communicating effectively with other health care professionals • Assist you in documenting findings, convey history information during medical referrals, and collaborate with other healthcare professionals regarding care of your athlete

4. Anatomical Reference Terminology • All anatomical descriptions and references are based on standardized position of the body • Anatomical Position • Allows us to reference specific body regions in relation to the body as a whole and one anatomical landmark to another • Avoid confusion and misinterpretation of your findings • Can be standing or supine (on the spine) • Standing most common and easiest to visualize

5. Anatomical Reference Terminology • Anatomical position • Feet together, flat on the ground, toes facing forward • Legs and knees straight and in line with hip, torso and head, which are also straight and facing forward • Upper limbs positioned at persons side, with elbows straight • Shoulders rotated so palms are facing forward

7. Anatomical Reference Terminology • Once in anatomical position one can begin to refer to specific structure using various anatomical terms • Describe position of body parts with reference to other body parts or the body as a whole • Also synonyms reserved for particular body regions • For example anterior=structure near front of body, and anterior surface of hands is referred to as palmar or ventral

9. Anatomical Reference Terminology • From anatomical position can also define three anatomical planes of movement useful in describing postural positions, motions, and function of various muscles and joints • Imaginary planes that separate the body into left and right (sagittal or median), top and bottom (Transverse), and front and back (frontal or coronal) • For example when nodding your head or flexing your elbow this occurs in the sagittal plane • Shaking your head no or rotating your palms so it is facing backwards takes plane in the transverse • Lifting arms out to the side occurs in the frontal plane

11. Anatomical Reference Terminology • Patient positioning terminology important and helpful for understanding starting positions for various medical testing • Supine (face up) and prone (face down) refers to patient laying down • Short sitting-patient sitting on edge of table with legs hanging off the edge • Long sitting patient sitting with legs out in front of them with legs on the table or floor

12. Physical Maturity Classifications • Allows us to define stages of physical growth • Normal anatomic and physiologic development from infancy to older adulthood • Infancy: (0-12 months) physical changes occur most rapidly. • Dependent neonate to a child learning motor skills such as turning, sitting, crawling and walking • Gain 3 x birth weight in this time • Childhood: (1-11 years) infancy to onset of puberty • Steady growth and development • Skeleton is immature with epiphyseal plates open to allow bones to elongate • 1-5 early childhood, 6-11 middle childhood

13. Physical Maturity Classifications • Adolescence: ( 11-13 through 18-20) • Onset of puberty through full skeletal maturity • Onset of Puberty marked by development of secondary sexual characteristics • Females: menarche, pubic hair, development of breast • Males: Deepening of voice, pubic hair, and facial hair • Skeletal maturity marked by full closure (ossification) of epiphyseal plates and cessation of further growth in height • Age at which bones complete ossification varies widely from early teens to early 20’s • Adulthood (18-40 years) • Indicate full skeletal maturity and development • Bone and muscle mass increase through 25 to 30 years of age after which mass levels off and then slowly declines

14. Middle adulthood (40-60 years) • Gradual decline in strength coordination and balance • Older adulthood (> 60 years) • Spans rest of human beings life • Accelerating decline in strength, coordination and balance • Highly individual depending on lifestyle, activity, nutrition and disease

15. Injury Mechanisms • Foundation of body movements made up of several simple machines • Levers, pulleys, and wedges among other more complex systems • Bodies capable of performing very intricate and detailed work along with incredible feats of strength, power and endurance • However, body influenced by internal and external mechanical forces that can negatively affect performance • Important to understand musculoskeletal system, physical properties of the musculoskeletal tissue, internal and external mechanical forces that can cause injury

16. Injury Mechanisms • Musculoskeletal Tissue • Five tissue types Categorized by Soft and Skeletal Tissue • Soft tissue • Muscles, tendons, ligaments, and cartilage • Skeletal Tissue • Bone

18. Injury Mechanisms • Musculoskeletal Tissue Properties • Degree and location of injury often determined by tissue strength • Musculoskeletal tissue has elastic and plastic (inelastic) properties. • Elastic properties manifested as response to loading, stress or mechanical forces that cause stretching or deformation of tissue • After stress is removed tissue returns to relatively normal state

19. Injury Mechanisms • Plastic Properties manifested at end range of elastic properties rendering tissue unable to return to normal state • Tissue retains some amount of deformation due to structural injury • Yield point: determined by specific amount or level of stress • Example: stretching a rubber band. Point at which it breaks is considered yield point • Enough force to eliminate elastic property recovery and cause rubber band to undergo plastic deformation

20. Injury Mechanisms • Athletic injuries occur much the same way • Tissue stress determined by amount of mechanical force divided by total area affected • If tissue stress, is low enough that tissue remains in elastic property zone patient may only occur minor injury or none at all • If stress in high enough to force tissue to plastic property zone injury severity and tissue damage more significant

21. Injury Mechanisms • Individuals and individual tissue have an ability to respond to and resist a certain amount of load or stress before deformation • As load or stress increases the potential for tissue deformation also increases • Type of force applied, along with the surface area acted upon by the force , also affects the injury • Given same velocity localized force can result in substantially greater tissue damage than the dame force applied over a broader surface area

23. Injury Mechanisms • Tissue damage may be the result: • unpredictable accident or injury • Overuse • Overload • Poor posture • Skeletal immaturity • Lack of conditioning • Improper mechanics • Fatigue • Inflexibility • Muscle imbalance • Genetics

24. Mechanical Forces • Stress or load applied to the body to cause injury or tissue deformation is a result of 1 of 5 types of mechanical force • Excessive compression • Squeezing or condensing of tissue due to external forces applied directly opposite of each other • Bruises (contusions) • Crushing injuries (compression fractures) • Pinching • Injuries due to direct impact

25. Mechanical Forces • Shear • Forces that cause tissue to “slide” over adjoining surfaces or structures in a parallel fashion • Brain injuries • Tibiofemoral translation injuries such as ACL and PCL injuries • Blisters • Lumbar spine injuries

26. Mechanical Forces • Torsion • Twisting mechanism that causes rotation along long axis or fixed point • Opposite ends of tissue are rotated in opposite directions • Example: Body rotating over Foot fixed or lower leg • Occurs to bones and ligaments

27. Tension • Stretching or lengthening of musculoskeletal tissue due to stress or strain • Caused by pulling or drawing apart • Pull of tissue in opposite direction causes tissue in between to stretch • Muscle strains or ruptures commonly caused by tension within the musculotendinous unit • Where muscle makes transition into tendon • Weak part of muscle

28. Mechanical Forces • Bending • Deformation of tissue into convex or concave shapes due to axial loading • Forces acting in opposite directions at different ends of tissue • Or significant impact to middle of tissue while the ends are stable • Convex surface undergoes tensile forces while concave surface undergoes compression forces • Example: Fibula fracture with direct blow

29. Mechanical Forces • Mechanical forces are not isolated • Usually 2 or more mechanical forces acting on tissue at one time • Complex mechanisms and forces that come together to cause injury • Example: Lateral blow to knee with foot planted • Compressive forces to lateral knee, bending force to medial knee, shear and tension forces to middle of knee • Valgus force: toward midline • Varrus Force: Away from midline

31. Time Classification Relating to Mechanism of Injury • Acute Injuries • Conditions that have sudden onset, short duration, and occur via mechanical forces that exceed elastic properties causing tissue deformation • Single traumatic event: blunt force trauma, dynamic overload of muscle, tendon, joint capsule or ligamentous tissue

32. Time Classification Relating to Mechanism of Injury • Chronic Injuries • Gradual onset, prolonged duration, and occur as a result of accumulation of minor insults or repetitive stresses • Exact mechanism not often known • Overuse, accumulative microtrauma, repetitive overloading, abnormal friction that is greater than body's ability to heal and recover before additional stress is added • “too much, too soon, too often” • Often more difficult to treat overuse (chronic) injuries than acute injuries

34. Injury Classifications • Sign: finding that is observable or that can be objectively measured • Swelling, discoloration, deformity • Crepitus: crackling, grating, or grinding sensation • Symptom: subjective complaint or an abnormal sensation the patient describes but cannot be directly observed • Pain, nausea, altered sensation, fatigue

35. Injury Classifications • Closed (Unexposed) Wounds: Injury that does not disrupt surface of skin • Contusion or bruise • Signs: swelling discoloration and deformity • Compression of soft tissue due to direct blow or impact • Damage to small capillaries in tissue • Local bleeding (hemorrhage), causing ecchymosis (discoloration of tissue), may be immediate or delayed

36. Contusion Severity • First degree: superficial damage, minimal swelling, localized tenderness, no limitations to strength or ROM • Second Degree: Increased pain and hemorrhage, increased area and depth of tissue damage, mild to moderate limitation sin ROM and muscle function or both • Third degree: severe tissue compression, severe pain, significant hemorrhage and development of hematoma • Significant limitations in ROM and muscle function • Suspect damage to deeper structures such as none

37. Closed Wounds • Sprains: injury to ligaments or capsular structure • Ligaments attach bone to bone • Injury occurs when 2 bones separate or go beyond normal ROM • First Degree: mild overstretching • Mild pain and tenderness, little or no disability • AROM and PROM not limited but some pain at end range • Firm definitive end point (feel) • Degree of swelling and discoloration not great indicator of severity

38. Sprain Severity • Second Degree: Further stretching and partial disruption or macro tearing of ligament • Moderate to sever pain • Point tenderness • Eccyhmosis • Swelling • ROM and normal function limited secondary to pain and swelling • Stress testing shows instability or laxity but still feel an end point

39. Sprain severity • Third Degree: Complete disruption or rupture or loss of ligament integrity • Associated with feeling or sound of a pop • Immediate pain and disability • Rapid swelling. Eccyhmosis and loss of function • Stress test shows moderate to severe instability with no firm end point “ soft or mushy” • Can be deceiving because Rom and stress testing less painful because ligament not intact

40. Strains • Stretching or tearing of muscle or tendon • Violent, forceful contraction or overstretching • Fatigue, lack of warm up muscle strength imbalance, and dyssynchrony

41. Strain Severity • First Degree: overstretching and micro tearing of muscle or tendon. • No gross fiber disruption • Mild pain and tenderness • Typically full AROM and PROM • Pain with resisted muscle contraction

42. Strain Severity • Second Degree: further stretching or partial tearing of muscle or tendon fibers • Immediate pain, localized tenderness and disability • Varying degrees of swelling, eccyhmosis, and decreased ROM and strength • Pain with active muscle contraction and passive muscle stretch • May have palpable defect

43. Strain Severity • Third Degree: Muscle or tendon completely ruptured • Audible pop • Immediate pain and loss of function • Palpable defect on superficial muscles • Muscle hemorrhage and diffuse swelling • ROM and strength may or may not be affected or painful

44. Injury Classifications • Open (Exposed) Wounds • Injuries that involve disruption of the skin • Caused by friction or blunt or sharp trauma • Susceptible to infection • Monitor for pus increased pain, redness, swelling, heat and red streaks running from wound to trunk • If signs of infection are present refer to medical professional

46. Injury Classifications • Bone and Joint Injuries • Closed Fractures: disruption in continuity of bone without disruption of skin surface • Traumatic (Acute): immediate pain, rapid swelling, bony tenderness, false joint, crepitus, deformity • Displaced fracture concern with secondary injury • Evaluate neurovascular status distal to fracture site • Stress Fracture: • S & S not always as obvious • Onset of pain is gradual • Pain or deep ache may be first noticeable during activity and subside with rest, • progresses to more constant pain if offending activity continues • Swelling is minimal and localized tenderness over fracture site

47. Bone and Joint Injuries • Epiphyseal Injury • Disruption of epiphysis or epiphyseal plate (growth plate) • Can cause premature closing and growth abnormalities • Dislocation • Complete disassociation of 2 joint surfaces • Forces cause joint to exceed passed its normal ROM • Severe Stretching or complete disruption of joint capsule and supporting ligaments • Pain swelling, loss of function, deformity • Subluxation • Incomplete disassociation of 2 joint surfaces • Disability, pain, selling and joint instability varies • Often history of sensation of joint slipping or giving out

48. Injury Classifications Nerve Injuries Nerve Injuries Neuropraxia: transient and reversible loss of nerve function Axontmesis: partial disruption of nerve Considerable atrophy and weakness due to prolonged healing 2 weeks to a year Neurotmesis: most severe nerve injury, complete severance of the nerve Neuralgia: achiness or pain along distribution of nerve secondary to irritation or inflammation Neuroma: thickening of a nerve or “nerve tumor”, secondary to chronic irritation or inflammation • Compression or tensioning of neural structure • Laceration of nerve can occur secondary to fracture, dislocation, penetrating trauma • Anesthesia: no sensation • Parathesia: tingling, burning, numbness • Hyperesthesia: hypersensitivity • Paralysis: complete loss of muscle function