Acute and Overuse Injuries

Mechanisms of Acute Injury

• Acute injuries happen during a single, identifiable traumatic event
• The cause is when force to a tissue exceeds its capacity
• This leads to tissue failure, macroscopic damage, and rapid symptom onset like pain and loss of function
• Sources of force are either extrinsic or intrinsic
• Extrinsic forces are external like a direct blow or collision
• Intrinsic forces are internal like muscle contractions or joint biomechanics
• Prevention involves modifying extrinsic and considering intrinsic factors

Mechanisms of Overuse Injuries

• Overuse injuries result from repetitive stress over time
• This leads to microscopic tissue damage
• Assessment involves comprehensive history and risk factor assessment like training and technique
• Causes include a sudden increase in training volume, poor footwear and biomechanical abnormalities
• Treatment involves addressing the cause, modifying activity, and specific exercises

Key Points for Revision

• A primary reason for injury is when demand on tissue exceeds its capacity
• Intrinsic risk factor examples: Muscle strength, endurance, flexibility, motor control, joint range, biomechanics, proprioception
• Extrinsic risk factor examples: Equipment, playing surface, sport rules, and training errors

Stages of Healing

• The healing process has three main phases
• The inflammatory response phase
• The fibroblastic repair phase
• The maturation-remodeling phase
• Each phase has varying characteristics and timelines depending on tissue type, age, lifestyle, and injury severity

Tissue Type: Indicators of Inflammatory Phase

• Muscle tissue indicators: pain, swelling, redness, warmth, loss of function
• Muscle signs and symptoms: Localized pain, swelling, redness, increased temperature, and limited range of motion
• Muscle Timeframe is 0-4 days
• Tendon tissue indicators: Swelling, pain, redness, warmth, and tenderness
• Tendon signs and symptoms: Localized swelling, pain, redness, warmth, and limited range of motion due to pain
• Tendon Timeframe is 1-7 days
• Ligament tissue indicators: Pain, swelling, redness, warmth, loss of function
• Ligament signs and symptoms: Localized pain, swelling, and increased redness
• Ligament Timeframe is 1-7 days
• Bone tissue indicators: Hematoma formation, pain, swelling, and redness
• Bone signs and symptoms: Pain, swelling, redness, warmth, and hematoma at the fracture site
• Bone Timeframe is 0-7 days

Inflammatory Response Phase

• This initial phase of the healing process is critical for normal tissue healing
• Redness, swelling, increased blood flow, and capillary permeability occur
• Chemical mediators like histamine and bradykinin are released
• Typically lasts less than a week and is marked by pain, swelling, and limited function
• Initial reaction includes both systemic and local inflammation
• Decreased collagen synthesis and an increase in inflammatory cells
• Tissue damage will trigger the release of chemical mediators
• This increases blood flow and capillary permeability, letting edema break down
• Edema inhibits contractile tissues and limits function
• Blood flow is needed for phagocytosis to clear tissue debris and pathogens
• It lasts about 2-3 days or longer depending on the extent of the damage

Fibroblastic Repair Phase

• Tissue repair begins with the formation of new capillaries and connective tissue (scar tissue)
• Type III collagen is deposited, providing a framework for tissue regeneration
• Reduced pain and swelling, and scar tissue formation characterize this phase
• Phase lasts from a few days to several weeks
• Catabolism of damaged tissue and its replacement
• New capillaries and connective tissue form to improve tissue integrity
• Type 3 collagen gets deposited in random spots
• It is a framework for rebuilding tissues
• Weakness is due to new and unused tissue
• Collagen fibres lie transversely instead of longitudinally

Tissue Type: Indicators of Fibroplastic Repair Phase

• Muscle tissue indicators: Decreased pain and inflammation, formation of scar tissue
• Muscle signs and symptoms: Reduced pain, minimal swelling, easier movement, and formation of scar tissue
• Muscle Timeframe is 2 days to 6 weeks
• Tendon: Collagen synthesis, reduced inflammation, increased strength.
• Tendon: Decreased pain, minimal swelling, improved range of motion, scar tissue formation.
• Tendon Timeframe: 2 to 8 weeks.
• Ligament: Collagen deposition, reduced inflammation, increased stability.
• Ligament: Reduced pain, minimal swelling, improved joint stability, scar tissue formation.
• Ligament Timeframe: 2 days to 8 weeks.
• Bone: Callus formation, reduced inflammation, increased stability.
• Bone: Decreased pain, minimal swelling, soft callus formation, improved stability.
• Bone Timeframe: 1-6 weeks.

Maturation-Remodeling Phase

• Newly formed tissue is strengthened and remodeled
• Type I collagen replaces Type III to improve tissue structure, strength, and function
• This phase can last from months to years with minimal pain and improved function
• Weaker tissue begins to strengthen and collagen shifts to stronger type 1 fibers to withstand loading
• Increased loading forces the new scar tissue to hypertrophy, therefore, get stronger and withstand load

Tissue Type: Indicators of Maturation Phase

• Muscle tissue indicators: Realignment of collagen fibers, increased tensile strength, return to full function
• Muscle signs and symptoms: Minimal pain, improved strength, flexibility, and full range of motion
• Muscle Timeframe is 3 weeks to 1 year
• Tendon: Collagen maturation and alignment, increased tensile strength, return to full function.
• Tendon: Minimal pain, improved strength and flexibility, full range of motion.
• Tendon Timeframe: 6 weeks to several months to beyond a year.
• Ligament: Collagen maturation and alignment, increased tensile strength, return to full function.
• Ligament: Minimal pain, improved joint stability, full range of motion.
• Ligament Timeframe: 6 weeks to several months.
• Bone: Bone remodeling, increased strength and stability, return to full function.
• Bone: Minimal pain, full weight-bearing capacity, full range of motion.
• Bone Timeframe: Several months to 1 year.

Clinical Observations and Variability

• Clinicians should identify signs and symptoms of each healing phase
• Swelling, redness, warmth, and changes in range of motion and function
• Observations help tailor exercise approaches to match the injury's severity and healing stage
• Healing timelines are general guides, not exact timeframes for all clients
• Age, lifestyle, and injury severity influence the progression through healing phases
• Clinicians should consider these when informing clients

Common Injuries and Rehabilitation

• Familiarity with common injuries across the musculoskeletal system helps with diagnosis and management
• Musculoskeletal injury rehabilitation is dynamic and structured
• It aims to restore function/performance, ensure safe return to activities, and minimize re-injury risk
• Process divided into phases with specific goals and interventions for tissue type and severity
• Knowing the goal of a phase will indicate the exercise stimulus

Phases of Injury Management

• Phase 1: Acute Management protects injured tissue and promotes optimal loading for healing
• PRICE, is often replaced with POLICE
• POLICE: Protection, Optimal Loading, Ice, Compression, Elevation
• Optimal loading balances regain of ROM and minimizes inflammatory processes
• Activation exercises start within 24 hours, depending on injury severity
• Phase 2: Goal is to Restore Activities of Daily Living and physical function
• Restore client's ability to perform daily activities, sports-specific, or occupation
• Exercise complexity gradually increases from single-joint to multi-joint movements
• Improve motor control, strength, and endurance while maintaining secondary functions like hip stability and ankle mobility
• Phase 3: Returning to Activities
• Reintroduce client to physically demanding and sport-specific activities
• Involves traditional strength and conditioning with higher complexity and velocity
• Achieving 90% of the uninjured side's strength/function is the goal
• This is monitored through tests like single-leg hop tests
• Readiness for this phase is critical for increased motor control around joints
• Phase 4: Prevention of Re-injury
• Focuses on addressing residual impairments improving performance and includes ongoing training
• Enhances muscle activation patterns, landing strategies, and overall endurance

Approach based on tissue, injury, severity

• Rehab depends on tissue type, injury and severity
• Early activation and gradual loading are essential to prevent muscle atrophy and promote healing
• Ligament injuries need focus on restoring joint stability and proprioception
• Tendon injuries benefit from eccentric loading exercises to stimulate tendon remodeling
• Severe injuries need longer periods of protection and gradual progression
• Mild injuries can tolerate more aggressive loading and faster progression
• Individual variability requires personalized plans, evaluation and adjustment to the patient's progress

Effective Planning and Goal Setting For Effective Rehab

• It requires detailed planning and integrates anatomical, biomechanical, sport-specific/occupational task knowledge
• Early goal setting and collaboration with the client are crucial
• Goals should be realistic, measurable, and adaptable
• Regular communication and reassessment keeps plan dynamic and focused

Challenges and Continuous Evaluation For Effective Rehab

• Rehab has challenges like recurrent pain, effusion, and range of motion deficits
• Reassess the rehab program, ensuring interventions target the intended impairments when progress stalls
• Multidisciplinary collaboration helps address underlying challenges and adjust the plan

Mechanotherapy Steps Across The Tissue Healing Phases

Tendon

• Inflammatory Phase
• Increased blood flow, inflammatory cell infiltration, and release of growth factors
• Protection and controlled loading to prevent excessive inflammation
• Gentle isometric contractions to maintain tendon integrity without overloading
• Proliferative Phase
• Collagen synthesis, fibroblast proliferation, and matrix formation
• Progressive loading to stimulate collagen alignment and tendon strength
• Eccentric and concentric-eccentric exercises at moderate intensity (40-60% of maximum)
• Remodeling Phase
• Collagen maturation, increased tendon stiffness, and improved mechanical properties
• High-intensity loading to enhance tendon stiffness and functional capacity
• High-intensity muscle contractions (70-90% of maximum), including eccentric, concentric-eccentric, and isometric exercises

Muscle

• Inflammatory Phase
• Inflammatory response, removal of damaged tissue, and initiation of repair:
• Protection and gentle mobilization to reduce inflammation and prevent atrophy:
• Gentle passive and active range of motion:
• Proliferative Phase
• Satellite cell activation, muscle fiber regeneration, and collagen deposition:
• Progressive loading to stimulate muscle hypertrophy and alignment of regenerating fibers:
• Progressive resistance exercises, starting with low intensity and gradually increasing:
• Remodeling Phase
• Muscle fiber maturation, increased muscle strength, and improved neuromuscular control:
• High-intensity resistance training to maximize muscle strength and functional recovery:
• High-intensity resistance exercises (70-90% of maximum), including concentric, eccentric, and isometric contractions:

Bone

• Inflammatory Phase
• Inflammatory response, recruitment of osteoclasts and osteoblasts, and initiation of bone repair
• Protection and controlled weight-bearing to prevent excessive inflammation and promote healing
• Partial weight-bearing and gentle loading to stimulate bone repair
• Proliferative Phase
• Osteoblast proliferation, collagen deposition, and formation of new bone tissue
• Progressive loading to stimulate bone formation and remodeling
• Progressive weight-bearing and dynamic loading exercises
• Remodeling Phase
• Bone maturation, increased bone density, and improved mechanical properties
• High-intensity loading to enhance bone strength and functional capacity
• High-intensity dynamic loading exercises, including weight-bearing and impact activities

Articular Cartilage

• Inflammatory Phase
• Inflammatory response, removal of damaged cartilage, and initiation of repair
• Protection and gentle mobilization to reduce inflammation and prevent further damage
• Gentle range of motion exercises to maintain joint mobility
• Proliferative Phase
• Chondrocyte proliferation, matrix synthesis, and formation of new cartilage tissue
• Progressive loading to stimulate cartilage repair and improve mechanical properties
• Moderate resistance training and neuromuscular exercises
• Remodeling Phase
• Cartilage maturation, increased proteoglycan content, and improved stiffness
• High-intensity loading to enhance cartilage quality and functional capacity
• High-intensity resistance and neuromuscular training while avoiding pain and swelling

Motor Control Training

• Neuromuscular training targets specific deficits from a clinical assessment
• Begins with smaller movements progressing to bigger movements; should be pain-free
• Develops neuromuscular control due to potential joint damage
• Strengthening neuromuscular control improves function and stability, despite sensory feedback impairment
• There are 4 components to joint stability for neuromuscular control
• Proprioception is body awareness and kinaesthesia is sensation of joint motion or acceleration
• Dynamic joint stabilization is muscles maintaining joint stability during movement, preparatory and reactive
• Reactive motor control is muscles reflexively responding to changes
• Functional motor patterns are sport- or activity-specific movement patterns
• Motor control training integrates into rehab programs; tailored to individual and injury
• Phase 1: Initial Phase focuses on Basic Stability and Proprioception to establish joint stability, improve proprioception, and reduce pain/inflammation
• Phase 1 takes place during the inflammatory, proliferative, and post-operative phases
• Phase 2: Intermediate Phase focuses on Dynamic Stability and Coordination to improve joint stability, enhance muscle coordination, and begin functional movement
• Phase 2 takes place from end of the inflammatory to the end of the proliferative stage
• Phase 3: Advanced Phase focuses on Function and Sport-Specific Training for reactive neuromuscular Control, and Functional Motor Patterns
• Goals: restore functional motor patterns, improve reactive neuromuscular control and prepare for return to sport or activity
• When: end of proliferative and remodelling phase of healing

Exercise Induced Hypoalgesia and Pain

• Hypoalgesia relieves pain through exercise, triggers release of pain reducing substances
• Different types of exercise have all shown to reduce pain, with isometrics have the greatest outcome
• Moderate to high intensities for both aerobic and isometric exercise have the greatest affect.

Epidemiology of Pain

• In Australia, 1/5 of adults >45 years have chronic pain
• In America, 100 million Americans suffer chronic pain
• Lower socioeconomic status, education, and unemployment are associated with experiencing pain
• Those with chronic pain are less likely to participate in recreational activity than those with acute pain
• Lower Back Pain (LBP) is the highest ranked form of chronic pain. Neck pain, migraines, and knee/shoulder pain listed after

Understanding Pain

• IASP definition of pain: "an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage"
• Pain is subjective and always real; it will vary from person to person
• Some require less intervention than others, but some require a multidisciplinary approach

Pain Classifications By Duration

• Acute pain: less than 3 months; recent onset; decreases, tissues heal; related tissue damage; sub-acute = 6 weeks -> 3 months
• Chronic pain: longer than 3 months; persists beyond healing; pain alarm dysfunction

Pain Classifications By Cause

• Somatic pain: skin, muscles, bones, joints
• Visceral pain: organs
• Cancer pain: due to treatment, often progressive, chronic and acute
• Non-cancer pain: chronic and acute, surgery, trauma, disease, headache, childbirth, nerve injury
• Idiopathic pain: unknown event/cause

Pain Classifications By Mechanisms

• Nociception Pain: Damage to non-neural tissue, triggers nociceptor activation, normal nervous system
• Neuropathic pain: Lesion/disease to somatosensory nervous system, abnormalities/trauma, e.g. spinal cord injury
• Nociplastic pain: Nerve damage, ongoing inflammation/damage, altered nociception, lasts >3 months, general region and increased pain sensitivity(light, sound, sleep, fatigue, cognitive)

Other Pain Terminology

• Allodynia: touch-related pain from non-painful stimulus; central sensitization and neuropathic pain
• Hyperalgesia: increased pain from normally painful stimulus; possibly central/peripheral sensitization if in affected area
• Hypoalgesia: diminished pain response to normal/painful stimulus
• Phantom pain: no tissue; amputation
• Referred pain: not the source; cardiac = arm
• Radicular pain: nerve-related irritation

Chronic Primary versus Secondary Musculoskeletal Pain

• Primary pain has one or more regions in body, emotional distress, interrupts ADLs, multiple times of subcategories
• The diagnostic criteria are more than 3 months, conjunction with emotional distress or interference of ADL, not another condition
• Secondary musculoskeletal pain is, bones, tissues, joints, tendons, vertebral column and related soft tissues, local/systemic etiologies
• The diagnostic criteria is chronic pain for more than 3 months, musculoskeletal disease and trigger nociceptors, pain unaccounted for by diagnosis

Factors Influencing All Pain Types

• Nerve Signals
• Past Experiences
• Emotional State
• Context and Environment
• Beliefs and Expectations
• Social and Cultural Factors

Brain Feedback Loop for Pain

• Increased Sensitivity
• Persistent Pain Signals
• Psychological and Emotional Factors
• Discrepancy in Evaluation
• Mismatched feedback loop

Pain Assessment

• Distinguishing nociceptive pain from neuropathic
• Nociceptive: acute sharp/throbbing pain recently with identical cause
• Neuropathic pain: burning, shooting, pins/needles, or electric-shock like
• Nociplastic pain diagnosis given last, lasts > three months and absence with identical cause

Methods for Pain Assessment

• Numerous methods include.
• Numerical, Visual Analogue, and Facial Pain Scales
• The neonatal infant pain scale is used for infants (facial expressions, body movements, arousal, breathing patterns)
• Face pain scale: older adults with cognitive deficits
• Behavioural pain scale: critically ill patients/ventilated, looks facial expressions, movement of the upper limbs and compliance with mechanical ventilation.
• Brief pain and West haven-yale inventories
• The LASS is able to classify patients with neuropathic pain