Mechanisms of injuries

Mechanisms of Injury

Tissue mechanics (bone, cartilage, tendon, ligament, muscle).
Biomechanics of injury mechanisms.
Prevention of injury.

Physical assessment

Perform a clinical history, orthopedic/neurologic examination.
Interpret the findings of clinical history/physical examination to arrive at a clinical impression/diagnosis.
- Impression and diagnosis have a very small difference.
  - Impression: a working hypothesis.
  - Diagnosis: the final conclusion.
Recognize key diagnostic features of musculoskeletal injury/disease.
Communicate findings to other health professionals/stakeholders.

Principles of Injury Management

Understand and apply principles of rehabilitation, injury management, prevention to the spectrum of musculoskeletal injury and disease.

Complex Systems

Interdependencies
Non-linear
Causal opacity
Self-organizing with emergent properties
- The body is no different than other complex systems such as nature.

Mechanism-based Diagnosis

Mechanism-based approach to healthcare focuses on identifying the specific cellular, molecular, mechanical processes that contribute to a patient’s condition and/or pain experience.
How is it applied?
- Using biomarkers and diagnostic tools to identify the specific biological processes/mechanisms.
  - Examples of biomarkers include:
    - Respiration
    - Heartrate
    - Brainwaves/Electrical signal
Why is this important?
- Tailor treatment plans to target specific underlying mechanisms/processes,leading to more targeted, effective and personalized management.

Evidence Based Practice (EBP)

“The conscientious explicit and judicious use of current best evidence in mkaing decisions about the care of the individual patient.” (Sackett D, 1996)
Best Research Evidence, Clinical Expertise, Patient Values & Preferences -> EDP
- Patient decides based of what you provide to them
The evidence alone does not define the decision - it informs the patient care process.
Integration of clincial expertise, patient values, and the best research evidence into the decision making process for patient care.

Hierarchy of Evidence Pyramid

Meta-analysis/Systematic reviews to gain insight

Hippocratic Oath

Prioritize Patient Safety:
- Treatment decisions
- Patient autonomy
- Confidentiality
- Continuing education
- Ethical dilemmas
- Non-maleficence vs beneficence
  - “Risk vs Benefit”
“First for no Harm”

Critical Thinking: Socratic Questioning

Breaking down complex ideas into simpler components.
Encouraging self-reflection and intellectual humility
Revealing contradictions, inconsistencies, and logical fallacies in thinking.
Challenging assumptions and exploring different perspectives.
“Why do I believe in this and why is it right?”

Is stretching therapeutic?

It depends…
- Start with saying “it depends” because it varies on what is the cause and what is happening.
Muscles don’t go into spasm without reason…
“The biggest mistake we have made in training over the last 10 years is ana active attempt to increase the static and active range of motion of an area that requires stability.
Most, if not all, of the many rotary exercises done for the lumbar spine were misdirected.”

Is Core Exercise Effective for Back Pain?

Depending on the type of core exercises that you complete(isometric vs stability) different muscles are activated. (obliques would not help with trapezius).
Strengthening relevant muscles with increased stability in the spine, alleviating back pain.
Disc issue has pain associated with flexion, thoracic expansion (breathing/sneezing), and bending. Core exercises aggravate this pain and should not be used for disc issues.

Does Therapeutic Ultrasound breakdown scar tissue?

Does not break down scar tissues (shockwave therapy breaks down scar tissue).
Therapeutic ultrasound is used for pain relief solely and should not be confused with shockwave therapy.

Overview of Tissues

Tissues: are collections of cells and cell products that perform specific, limited functions.
All connective tissues has characteristic features:

Specialized cells

fibrocytes, chondrocytes and osteocytes

Extracellular protein fibers

Collagen ‐ abundant in tendons and bone; high tensile strength
Elastic fiber ‐ found in the walls of arteries and in flexible cartilage like the epiglottis; provides resilience.
Reticular fiber is the support material of soft organs like the spleen and liver.

Fluid ground substance

Complex mixture of organic and inorganic materials
Fills the spaces between the cells and fibers
Nutrition

2 and 3 = Extracellular Matrix (ECM) (greatest % by vol)

Collagen
- Most abundant protein in mammals (25-35% whole body content).
  - Produced by fibroblasts (24 hour post-injury)
  - At least 28 different types
  - Over 90% is TYPE I (skin, tendon, ligament, bone, scar)
  - Type II (hyaline cartilage)
- Long fibrous, helical protein vs globular (enzyme)
- High tensile strength - along 1(degree) axis
- Provides structure to tissues
- Major component of scar tissue
Fibrosis (scar tissue)
- Factors increasing the production of collagen:
  - Chronic inflammation
  - reinjury/repetitive injury or exposure to suprathreshold forces
- Factors affecting strength of scar:
  - The number and strength of inter/intra molecular crosslinks impart tensile strength to collagen fibers
    - Cross-links can be weakened by:
      - Application of salt water, alcohol
      - Vibration, heat, enzymes
      - Immobilization
      - Reinjury during scar formation
        Challenge?
  - Alignment of tropocollagen
- In order to Optimize Collagen Alignment during the rehabilitation of injured tissues:
  - Low-load, long duration, sub-threshold force, enhances collagen alignment along lines of force**
Dense Regular CT: tendons, ligaments
- Dense REgular CT:
  - Tightly paced parallel fibers
  - Minimal matrix
  - Aligned along primary force axis of tissue
- FOUND in:
  - Tendons/Aponeuroses:
    - Bone to muscle
    - Predominantly collagen WHY?
  - Ligaments:
    - Bone to bone
    - Predominantly elastin
- Function:
  - Firm attachment of muscle/bone
  - Reduce friction between muscles (fascia)
  - Biomechanical
Dense Irregular CT
- Thick collagenous fibers
- No pattern-interwoven mesh
- Applied forces from many directions
- Encapsulates organs (kidneys, spleen), joints, beneath dermis
- Encircles bone (periosteum) & cartilage (perichrondrium)
Elastic CT
- Predominantly found in ligaments
- Location:
  - Spine: ligamentum flavum, ligamentum nuchae
- Function:
  - Stabilizes vertebrae
  - Reduced tensile strength vs tendon
    - Allows for full flexion while protection from hyperflexion injury
Fluid Connective Tissue-Blood
- Structure: plasma, red blood cells (RBC’s), white blood cells (WBC’s).
  - Conists of formed elements or cells and a liquid ground substance called plasma.
  - The cells are primarily erythrocytes (RBC’s) and leukocytes (WBC’s).
- Fibers are only found in the blood during the process of clotting.
- Functions - transportation and protection
  - Transportation of respiratory gases, nutrients, hormones. O2 is carried by the hemoglobin in the RBCs.
  - Protection against infection by circulating WBCs. Protection against blood loss by platelets - clotting.
  - Temperature regulation.
Supporting CTL Cartilage Hyaline Cartilage (articular)
- Function
  - Stiff but flexible support
  - Reduce friction
- Characteristics
  - Abundant ground substance (matrix)
  - Matrix consists of chondroitin sulphate
  - Has a perichondrium
- Location
  - End of bones
  - Epiphyseal plate
  - Larynx
  - trache /bronchi
  - Nasal septum
Supporting CT: Elastic Cartilage
- Similar to hyaline cartilage EXCEPT it contains abundant elastic fiber in the matrix.
- Restores to original shape.
- Elastic fiber gives it a yellow colour
- Pinna, tip of nose, epiglottis (larynx)
Supporting CT: Fibrocartilage
- Key Feature:
  - Matrix is dominated by densely interwoven coarse collagenous fibers arrange in bundles
  - Little ground substance (vs hyaline)
- Function: resist compression, absorb shock, areas of heavy loads.
- Cartilage cells are arranged between collagenous bundles often in rows. This cartilage lacks a perichondrium
- It is found in the intervertebral disks, meniscus, pubic symphysis and the lining of tendon grooves.
Supporting Connective Tissue-compact Bone
- Unique feature of this CT is that bone matrix mineralizes
- Compact bone consists of bone matrix laid called lamellae
- The lamellae surround a central Haversian canal (Hc)
  - Contains blood vessels, nerves and lymphatics.
- Osteocytes are arranged in concentric rings around the central Haversian canal.
- Very delicate thread-like lines (canaliculi) can be seen connecting the black osteocytes (oc) with the Haversian canal.
- Compact bone is found around the shafts of diaphyses of long bones
Anatomical Position and Descriptive Terms
- Anatomical position: standing upright, facing forward, arms at the sides, palms facing forward, feet slightly apart.
Major Cavities in Human Body

Planes and Sections
- To describe internal anatomy, orientation points, increase visibility.
- Plane: an imaginary flat surface that separates two portions of the body.
- Sections: cuts in a body or organ that make the structures more easily visible.
  - Frontal or coronal section - separates the body into front and back sections.
  - Sagittal section - separates the body into right and left portions.
  - Transverse (cross) section - separates the body into upper and lower sections.