Week 3 tendon injuries

• What do tendons attach to bones?

  Muscle
• What type of tissue are tendons made of?

  Fibrous connective tissue
• Are tendons vascular or avascular?

  Avascular
• What is the shape of tendons?

  Cord-like or flat ribbons
• In which direction do tendons transmit tension?

  In one direction
• What are the components of tendon composition?

  • Paratenon
  • Endotenon
  • Tropocollagen

  
• How many polypeptide helices make up a tropocollagen superhelix?

  Three polypeptide helices
• How many amino acids are in each tropocollagen helix?

  Around 1000 amino acids
• What does the toe-in region of the stress-strain relationship represent?

  "Un-crimping" of collagen fibrils
• What happens to the tendon when strained up to 2%?

  The tendon is strained without deformation
• What occurs when strain remains less than 4%?

  The tendon returns to its original length
• What is the load at which microscopic failure occurs?

  When the load exceeds 4%
• What is the load at which macroscopic failure occurs?

  Beyond 8-10% strain
• What is tensile strength related to in tendons?

  Thickness and collagen content
• How much weight can an area of 1cm² of tendon bear?

  500-1000 kg
• What forces have been recorded during running and jumping activities?

  12.5 times body weight
• When are tendons most at risk of injury?

  When force is applied quickly and obliquely

  
• What happens at larger strains in tendons?

  Micro-damage occurs leading to macro-damage

  
• What is hysteresis in the context of tendons?

  Energy lost during unloading
• What does the load-elongation curve indicate?

  Greater deformation with the same stress

  
• What are the histopathological changes in tendinopathy?

  • Rounder, more numerous tenocytes
  • Evidence of oxidative damage
  • Increased apoptosis
  • More water in the matrix
  • Cartilage-like proteins
  • Less organized collagen

  
• What mediates the repair mechanism in tendons?

  Resident tenocytes
• What can cause tendon damage within physiological limits?

  Cumulative microtrauma without repair time

  
• What can result from non-uniform stress within tendons?

  Localized fiber damage

  
• What are the signs and symptoms of Achilles tendinopathy?

  • Gradual onset of pain
  • Sharp pain or palpitations
  • Worse in the morning
  • Worse on commencing activity
  • Joint stiffness
  • Decrease in dorsi-flexion
  • Palpable thickening/nodule
  • Marked swelling
• How does the tendinopathic tendon differ from a healthy tendon?

  More compliant, less strong, absorbs less energy
• What are the risk factors for Achilles tendinopathy?

  • Repetitive movements
  • Age (30-60 years)
  • Poor form/equipment
  • Overplaying
• What is tennis elbow often caused by?

  Repetitive movements of wrist and arm
• What is a common age range for tennis elbow?

  Adults ages 30-60
• What injury mechanism is associated with lateral epicondylitis?

  Fast muscle contraction in lengthened position
• What type of injuries can occur in sports?

  Acute, chronic, or recurrent injuries
• What causes shoulder impingement syndrome (SIS)?

  Pressure from calcium build-up
• What are the signs and symptoms of calcific tendonitis?

  Sudden onset of intense shoulder pain
• What can cause loss of shoulder range of motion?

  Stiffness of the shoulder
• What is a risk factor for shoulder impingement syndrome?

  Acromion type
• What are the treatment options for shoulder impingement syndrome?

  • Corticosteroid injections
  • Initial period of rest
  • Mild discomfort exercises
  • Shoulder impingement exercises
• What are the signs and symptoms of shoulder dislocation?

  Visible drop of humeral head
• What is a common sensation when a shoulder dislocates?

  Feeling it pop out
• What is a common position for comfort after a shoulder dislocation?

  Position where they are most comfortable
• What nerve damage can occur with shoulder dislocation?

  Axillary nerve damage