Tendons and Ligaments L3: Pathology and rehabilitation of tendons and ligaments

Question 1

Combination of structure-combination-function on tendons and ligaments

Answer 1

• Tendon & ligament can change their structure and/or composition (and thus their function) in response to changes physiology (maturation, ageing), injury or other disease processes
• If one structure at joint is affected, the total function of the joint will be disrupted
• Rehabilitation should consider behaviour of all the affected structures/ induce adaptation in each structure.

Question 2

What are the 2 functions of ligaments?

Answer 2

• Strong enough to provide stability
• Flexible enough to permit joint motion

Question 3

What are the mechanics of injury of ligaments?

Answer 3

• Ligaments fail when tensile loads exceeds capacity
• Often awkward position of landing
• Joint dislocation is often associated with ligament damage
• Abnormal motion between bony articulation predisposes to articular damage ¥ Eg. lateral ankle is common
• Sublaxation = partial dislocation often strain (not torn) ligament
• Collagen fails progressively (ligament) vs rapidly (tendon)
  
  • Grade 1: damage to some collagen fibres
    
    • Ev/inv tears
  • Grade 2: more extensive number of fibres damaged
  • Grade 3: complete rupture
    
    • More laxity, end feel not from ligament

Question 4

What are the 3 grades of failure of ligaments?

Answer 4

1. Grade 1: damage to some collagen fibres
   
   • Ev/inv tears
2. Grade 2: more extensive number of fibres damaged
3. Grade 3: complete rupture
   
   • More laxity, end feel not from ligament

Question 5

Ligament healing is a continuous process? True or false?

Answer 5

True

Question 6

What are the 3 phases (triphasic) of ligament healing?

Answer 6

1. Inflammation
   
   • Swelling
2. Proliferation
   
   • Layng down new tissue
3. Remodelling
   
   • Collagen fibres in direction of stress

Question 7

What are the 3 mechanical properties of ligament healing?

Answer 7

1. Decreased stiffness (lower slopes)
2. Decreased load at failure (all times)
3. Altered site of failure (entire ligament is weakened)

Question 8

What are the 3 morphology properties of ligament healing?

Answer 8

1. Increased cross-sectional area (all times)
2. Progressive decrease in CSA from 3-14wks
3. Increased laxity at 3, 6, and 40wk

Question 9

When should extra-articular ligament (outside capsule) be operated on?

Answer 9

• High healing capacity
• Often treating conservatively
• Eg. ankle, collateral ligaments of knee/elbow

Question 10

When should intra-articular ligament (inside joint) be operated on?

Answer 10

• Lower healing capacity
• Often require surgery
• Eg. ACL, PCL , scapholunate ligament (wrist)

Question 11

Ligaments are associated with…

Answer 11

• Instability (increased ROM)
• Bony bruising (bone on bone interaction)
• Osteoarthritis (if ligament damage remains, or ligament not healed properly)

Question 12

What are 3 questions that should be asked in regards to rehabilitation?

Answer 12

1. What structure is damaged & to what extent? (grade level)
2. What is the timeframe of healing response?
3. What are the priorities at this timepoint?
   
   • Inflammation?

Question 13

What are 4 characteristics of a normal ligament?

Answer 13

1. Hypocellular ( decreased cell density)
2. Hypovascular ( decreased blood)
3. Highly organised
4. Dense collagen structure

Question 14

What are processes that occur during injury, on a time line?

Answer 14

Question 15

What are processes that occur during injury, at 10 days?

Answer 15

Defect filled with vascular inflammatory tissue

Question 16

What are processes that occur during injury, at 3 weeks?

Answer 16

inflammatory cells subsided and active fibroblasts dominated

Question 17

What are processes that occur during injury, at 6 weeks?

Answer 17

decrease in number and size of fibroblasts + some evidence of longitudinal alignment of nuclei (along long axis of ligament)

Question 18

What are processes that occur during injury, at 14 weeks?

Answer 18

remodelling – increased realignment and decreased cell numbers

Question 19

What are processes that occur during injury, at 14-40 weeks?

Answer 19

few changes noted; cells remained larger and more numerous

Question 20

What are the 3 mechanical properties of ligament healing?

Answer 20

1. Mechanical properties of healing MCL substance remain inferior to normal ligament (sham surgery) for up to one year
2. MCL may increase stiffness by increasing CSA of healing ligament by as much as 2 ½ times normal size
3. Healed ligaments are generally more bulky and not as strong as native tissue

Question 21

What are the 3 functions of tendons?

Answer 21

• Transmit tensile forces
  
  • Mechanical properties of tendon affect muscle function (force generating capacity + muscle length-tension relationship)
• Storage & release of energy for efficiency
• Buffering, amplifying role

Question 22

What are 11 mechanism for tendon injury?

Answer 22

1. Excessive force
2. Repeated overload
3. Normal forces applied to weakened tendon
4. Stress-shielding
   
   • Even if whole tendon is exposed to normal mechanical loading, some fibres may be underloaded (stress-shielded) and other fibres over-loaded
   • Eg: Lower strain in proximal posterior part of healthy patellar tendons
5. Forces applied in alternative direction o Tendon compression frequently contributes to insertional tendinopathy
   
   • eg: Achilles or Gluteus medius tendons
6. Ageing
7. Adiposity
   
   • mechanical loads + systemic effects
8. Physical activity levels
   
   • spikes in acute load relative to chronic loads
9. Diseases
   
   • e.g. diabetes, rheumatoid arthritis
10. Medications
    
    • e.g. corticosteroids - suppresses fibroblastic reaction and inhibits growth
11. Alcohol
    
    • inhibits fibroblast proliferation

• Degenerative changes may weaken the tendon’s mechanical properties predisposing to injury
• 97% of ruptured Achilles tendons had asymptomatic (didn’t feel) degenerative changes

Question 23

Where are the 3 places that overuse tendinopathy can occur?

Answer 23

1. Midsubstance (red) (e.g. Achilles)
2. Insertional (blue) (e.g. Achilles, lateral elbow (tennis elbow), patellar tendinopathy
3. Musculotendinous junction (e.g. hamstrings, quadriceps tendon)

Question 24

What are characteristics of an overuse tendinopathy?

Answer 24

• Grey and amorphous to naked eye
• Disorganised collagen (separation, fragmentation, disorientation)
• Inflammatory & immune cells absent
• cellularity
• Hypervascularity
• proteoglycans and water content

Question 25

What are characteristics of a normal tendon?

Answer 25

* Highly organised, relatively few cells * Glistening white

Question 26

What are some changes in mechanical properties in tendons?

Answer 26

* Reduced Achilles tendon stiffness in Achilles tendinopathy

Question 27

Why would ultrasound imaging be used in tendinopathy?

Answer 27

* Demonstrates tendon thickening, hypoechoic areas, tears (B-mode) * Neovessels (Doppler)

Question 28

\_\_\_ sensitivity and ____ specificity for diagnosis of tendinopathy = negative ultrasound = useful to rule out tendinopathy

Answer 28

High; low

Question 29

There is a limited correlation with pain severity in tendinopathy? True or false

Answer 29

True

Question 30

What are some changes in elastic properties?

Answer 30

* A and P tendinopathy subject had lower Achilles tendon elastic modulus and higher patellar tendon elastic modulus. * General rule- higher velocity = increased stiffness

Question 31

What is one of the most critical components of rehabilitation for tendinopathy?

Answer 31

Exercise

Question 32

Why is exercise a critical rehab option for tendinopathy?

Answer 32

* Isometric exercise possibly superior ? * Improve function * Progressive loading to remodel tendon * Avoid compressive loading, especially if insertional * (eg: prox hamstrings) * Considerations… * What is the loading history ? * Gradual progression of loads * Address stability/coordination * No quick fixes (slow turnover)

Question 33

What is paratendinitis?

Answer 33

* Occurs where a tendon rubs over a bony protuberance * De Quervains (APL, EPL) * FHL (near medial maleolus) * Acute oedema, hyperaemia of paratenon * Inflammatory cells * Tendon itself minimally involved * Crepitis (fibrinous exudate fills shealth)

Question 34

What is a tendon rupture?

Answer 34

* Can occur in normal tendon if loads are sufficiently large * Common tendons * Rotator cuff (older adults) * Achilles (young, active adults) * More commonly occurs in tendon weakened by pre-existing degenerative change (diabetes, alcohol)

Question 35

How to assess tendon pathology?

Answer 35

Question 36

What are the effects of immobolisation on tendons and ligaments?

Answer 36

* decreased structural properties of tendons/ligaments * Immature, weaker, disorganized collagen * decreased tissue stiffness up to 50% after 8 weeks of immobilisation * Tissue deterioration is less if immobilised in some tension

Question 37

What are the effects of remobilisation and recovery?

Answer 37

* Re-establishment of normal stresses can reverse effects, but … * Tendons/ligaments are relatively hypovascular + hypocellular * **Healing is slow** - takes many months and may never attain past characteristics * **Insertion sites** are **more resistant to recovery**

Question 38

What are some exercise training concepts to understand as rehabilitation?

Answer 38

* Progressive loading to improve tendon “capacity” * Increased strength = increased energy storage = store and release