1. Injury and the Healing Process

2. Introduction to Injury
When an injury takes place some responses are predictable, but others are unexpected
It is not clear if the stages are the same in acute and chronic injuries
An athletes point of view of an injury
Painful problem that prevents or hampers sport performance

3. Tissue Damage Microscopic trauma Macroscopic trauma
Involves damage to a structure at a microscopic level
Macroscopic trauma
Is obvious, visible damage to a structure
Individual cell holds the key to the regulation of the body’s trauma response

4. Sports Medicine Goals When an injury occurs the sports med team
Minimize the adverse effects of traumatic inflammatory response
Promoting tissue repair
Expediting a safe return to performance
Challenged to understand and anticipate the cellular response in predicting the recovery from injury

5. Injury Mechanisms
Human movement during sport and exercise is typically faster and or produces greater force
As a result, the potential for injury is also heightened
Understanding the different forces that act upon the body- you can understand how to prevent injuries

6. Force Defined as a push or a pull acting on the body
When a force is sustained by body tissue, two factors help determine if injury occurs
The size and magnitude of the force
The material properties of the involved tissues

7. Magnitude of Force Small forces Large forces
The response of the loaded structure is elastic
When the load is removed the material will return to its original size and shape
Large forces
Exceeds the materials elastic limits- the structure is unable to elastically rebound to its original shape
Some amount of deformation results

8. Magnitude of Force Larger forces
Exceed the material’s ultimate failure limit
Produces mechanical failure of the structure
Translates to a bone fracture or rupturing of a soft tissue

9. Direction
The direction of force is applied has important implications for injury potential
Many tissues are stronger in resisting force from some directions than from others
Lateral ankle sprains are much more common than medial ankle sprains, because ligament support of the ankle is much stronger on the medial side

10. Categories of Force
Force acting along the long axis of a structure is an Axial force
4 categories of force
Compression
Tension
Shear
Torque

11. Compressive Force
Axial load that produces a squeezing or crushing effect is a compressive force
Weight of the human body constantly produces compression on the bones
When a football player is sandwiched between two tacklers, the force upon the player is compressive
Often result in bruises or contusions

12. Tensile Force
Axial loading in the direction opposite of that of compression in called tension
Pulling force that stretches the object to which it is applied
Muscle contraction produces a tensile force on the attached bone, enabling movement
When the ankle is inverted, the tensile force results in an ankle sprain

13. Shear Force
Force that acts parallel or tangent to a plane passing through an object
Tends to cause one part of the object to slide, displace, or shear with respect to another part of the object

14. Torque A rotary or twisting force is termed torque or torsion
Excessive torque's can produce injury
Usually generated by forces external to the body rather than by the muscles
Torsion results in the creation of shear stress throughout a structure
Causing such injuries as a spiral fracture

15. Stress
When a given force is distributed over a larger area, the resulting stress is less than if the force where distributed over a smaller area
If a force is concentrated over a small area, the mechanical stress is relatively high
Football and hockey pads- distribute any force sustained across the entire pad, thereby reducing the stress acting on the player

16. Strain
The amount of deformation an object undergoes in response to an applied force
Application of a compressive force to an object produces shortening and widening of a structure
Tensile force produces lengthening and narrowing of a structure
Shear results in internal changes in the structure acted upon

17. Acute vs. Chronic Acute Injury Chronic Injury
Caused by a single traumatic force
Force is of large magnitude
Definitive moment of onset
Predictable process of healing
Macrotrauma
Ruptured ACL
Fractured Humerus
Chronic Injury
Cased by repeated forces
Force is of small magnitude
Over a period of time
Stress injury
Microtrauma
Starts when pain and inflammation become evident
May persist for months or even years

18. Body’s Response to Force
Tendon, ligament, muscle and bone respond to gradually increased stress by becoming larger and stronger
Overuse syndromes and stress fractures result from the body’s inability to adapt to an increased training regimen

19. Soft Tissue Injuries
Behave in characteristic ways when subjected to different forms of loading
Skin
Tendon
Ligament
Muscle

20. Collagen Major building block of soft tissue
Protein that is strong in resisting tension
Allows tissues to stretch slightly under tensile loading, providing flexibility

21. Skin Injuries Skin is the body’s first layer of defense against injury
Most frequently injured body tissue
Different Types of Skin Injuries
Abrasions
Blisters
Skin Bruises
Incision
Laceration
Puncture Wound

22. Abrasions Minor skin injuries Caused by a shear force
Skin is scraped with sufficient force, usually in one direction, against a rough surface
The greater the applied force, the more layers of skin that are scraped away

23. Blisters Minor skin injuries
Caused by repeated application of shear in one or more directions
Occurs when a shoe rubs back and forth against foot
Result is the formation of a pocket of fluid between the multiple layers of skin

24. Skin Bruises Contusion
Injuries resulting from compression sustained during a blow
Damage of the underlying capillaries
Causes the accumulation of blood within the skin

25. Incision and Laceration
Clean cut
Produced by the application of a tensile force to the skin as it is stretched along a sharp edge
Laceration
Irregular tear in the skin
Typically results from a combination of tension and shear

26. Puncture Wound
Formed when a sharp object penetrates the skin and underlying tissues with tensile loading
Puncture wound can come from:
Shoe spike
Nail

27. Categories of Injury Muscle bruises or contusion
Result from compression sustained from heavier blows
Injuries vary in severity according to the area and depth over which blood vessels are ruptured
Rated according to the extent to which associated joint range of motion is impaired

28. Categories of Injuries
Strain and Sprains
Caused by an abnormally high tensile force that produces rupturing of the tissue and subsequent hemorrhage and swelling
Categorized as first, second, and third degree injuries

29. First Degree Injuries Some pain
Only involve micro-tearing of the fibers
No readily observable symptoms
Mild discomfort
Local tenderness
Mild swelling
Ecchymosis
NO loss of function

30. Second Degree Injury More severe pain
More extensive rupturing of the tissue
Detectable joint instability
Muscle weakness
Limited joint range of motion

31. Third Degree Injury Produce severe pain
Major loss of tissue continuity
Loss of range of motion
Complete instability of the joint

32. Tendonitis Chronic condition
Characterized by pain and swelling with tendon movement
Prolonged chronic inflammation of muscle or tendon can result in the accumulation of mineral deposits, known as calcification

33. Bursitis
Involves irritation of one or more bursa, the fluid filled sacs
Serve to reduce friction in the tissues surrounding joints
Can be acute or chronic

34. Soft Tissue Healing
Normal healing process takes place in a regular and predictable fashion
Three Phases
Acute Response
Repair and Regeneration
Remodeling

35. Acute Phase Also known as the reaction phase
Lasts for the first several days following an injury
Inflammation is major reaction in this phase
Characteristics of the inflammatory process:
Redness, Local Heat, Swelling
Pain and Loss of Function

36. Vasoconstriction Vasoconstriction occurs in the acute phase
Curtails the loss of blood
Enables initiation of clotting
Hypoxia and Necrosis occur due to lack of oxygen and blood in the area
Hypoxia
Reduced oxygen in tissue
Necrosis
Death of tissue

37. Vasodilatation Vasodilatation also occurs in the acute phase
Occurs after vasoconstriction
Brought on by chemicals released by the body
Increased blood flow causes swelling in area of injury
Broken blood vessels and damaged cells form a hematoma
Speeds the arrival of specialized cells that will ingest dead cells and any foreign material or infectious agents
The resulting swelling also stimulates nerve endings to cause pain

38. Repair and Regeneration Phase
Takes place from about 2 days following the injury through the next 6-8 weeks
Begins when hematoma has diminished in size allowing room for growth of new tissue
Except for skin, all other soft tissues replace damaged cells with scar tissue
Healing begins with the accumulation of fibroblasts to produce scar tissue

39. Repair and Regeneration Phase Cont…
Fibroblasts begin to produce immature collagen
The scar tissue that is formed is less strong and less functional than the original tissue
Development of the scar also causes the wound to shrink in size, resulting in decreased flexibility of the affected tissue

40. Remodeling Phase
Begins about 3 weeks post injury, overlapping the repair and regeneration phase and continues for a year or more
Maturation of the newly formed tissue
Decreased fibroblast activity
Organization of the tissues increases and normal chemical activity resumes

41. Severe Muscle Injuries
Severe muscle injuries can result in scarring or the formation of adhesions
After severe injury, muscle may regain only about 50% of its pre-injury strength
Adhesions
Tissues that bind the healing tissue to adjacent structures
Happens within the muscle
Inhibits muscle fiber regeneration

42. Tendon and ligament injuries
Have few reparative cells
Healing may take more than a year
If these tissues undergo abnormally high tensile stress before scar formation is complete, the newly formed tissues can be elongated
This may result in permanent joint instability

43. Bone Injury Healing Three Phases Process Acute Phase
Repair and Regeneration
Remodeling Phase

44. Acute Phase Last approximately 4 days Hematoma is formed
Vasodilatation occurs
Edema
Tissue chemical changes

45. Repair and Regeneration Phase
Osteoclasts come to the area of injury to reabsorb damaged bone tissue
Osteoblasts build new bone
A callus is forms between the fractured bone ends
A callus is a fibrous vascularized tissue containing immature bone
Strengthens with time through remodeling phase
Fixation devices are only implanted when it appears unlikely that the fracture will not heal properly

46. Remodeling Phase
Osteoblasts and Osteoclasts activity continues until normal shape and strength has restored
Time is the largest requirement for proper none union to take place
Complete remodeling may take many years

47. Nerve Injuries Most commonly injured by tensile or compressive forces
When a nerve is loaded with tension, the nerve fibers tend to rupture prior to the rupturing of the surrounding tissue
The nerve roots on the spinal cord are not protected by connective tissue and are particularly susceptible to tensile injury, especially stretching of the brachial and cervical plexus

48. Compression Injury to Nerves
More complex
Severity depends on the magnitude and duration of the loading force
Nerve function is highly dependent on oxygen provided by blood vessels
Damage to the blood supply caused by a compressive injury results in damage to the nerve

49. Nerve Injuries Symptoms can range Pain Discomfort
Complete loss of sensation
Chronic irritation/inflammation
Lead to chronic pain along the nerve’s path
Pinching of a nerve
Results in a sharp wave of pain that is transmitted through a body segment

50. Nerve Healing Completely severed nerve Incomplete nerve injury
Healing does not occur
Loss of function is typically permanent
Incomplete nerve injury
Sometimes possible for regeneration
Regeneration is relatively slow

51. Pain Universal Symptom common to most injuries
Individual’s perception of pain is influenced by four factors:
Physical
Chemical
Social
Psychological

52. Neurological Basis of Pain
Small diameter, slow transmission nerves carry pain impulses
Fast transmission nerves carry other sensations: touch, temperature, proprioception
Located in superficial skin layers
Can be stimulated by mechanical stresses such as trauma, swelling, and muscle spasm
Other pain receptors are chemo-sensitive
Pain threshold can become progressively lower

53. Gate Control Theory
Spinal cord is organized in such a way that pain or other sensations may be experienced
An area or “gate” within the spinal cord organizes input stimulus and transmits stimulus to the brain
Therefore, stimulation from the larger, faster nerves can selectively “close the gate” to the smaller, slower pain fibers
Concept explains why cold can numb the pain as well as why acupuncture, acupressure and skin irritants provide some relief against pain

54. Factors That Mediate Pain
Body produces natural “pain killers” that are chemicals similar to morphine called endorphins
Endorphins block nerve receptors sites that transmit pain
Pain is a mixture of physiological and psychological factors
Individuals vary in their pain thresholds

55. Referred Pain
Pain that is perceived at a location remote from the injury site
Pain is thought of as an error in perception on the part of the brain and body
Some referred pain is predictable
Heart attack-left shoulder and arm
Spleen- left shoulder/arm

56. Nutrition and Healing
Proper nutrition is essential to provide the necessary nutrients for wound healing
Proteins
Vital role in repair, growth and maintenance of body tissue
Carbohydrates
Main energy fuel for the body and important for repair and healing

57. Nutrition and Healing Vitamins Supplements
Important role in wound healing
Vitamin B, C, A,E, and K are all important
Supplements
Are not necessary for healing as long as athlete diet is nutritionally balanced

58. The End
Any Questions??