Ligament Injury

Question 1

What is the role of ligaments?

Answer 1

• Passive guidance of joint motion
• Stability
• Proprioception (feedback of joint position)

Question 2

What is the gross appearance of ligaments?

Answer 2

• White
• Shiny
• Hard
• Synovial covering tissue

Question 3

What is the structure of ligaments?

Answer 3

65% water
Dry weight:
- 75-85% type 1 collagen
- 10% type 3
- Proteoglycans
- 1-2% elastin
- Up to 20% unknown

Question 4

What do many ligaments blend with?

Answer 4

Synovial joint capsule e.g. glenohumeral joint capsule

Question 5

What are some of the differences between ligaments?

Answer 5

• Anatomical variations
• Different cell density
• Different stiffness
• Synovial sheaths/capsules
• Proprioceptive functions
• Different distributions of vascularity/nerve endings
• Age-related

Question 6

What are the 3 regions of the force/deformation graph (stress/strain)?

Answer 6

• Toe region: Uncrimping of collagen fibres
• Linear region (elastic zone): Linear resistance to movement
• Yield/failure region:

**Know for exam!

Question 7

What are some of the age related differences between ligaments?

Answer 7

• Children much softer/elastic
• Skeletal maturity
• Hormonal changes (relaxin)

Question 8

What is the optimum age for ligament strength?

Answer 8

18-22

Question 9

What is creep, load relaxation and hysteresis?

Answer 9

Creep: Lig will stretch over time with constant load
Load relaxation: If lig length is held constant, load in lig will decrease over time
Hysteresis: Repeated loading will lengthen the lig

Question 10

What is the difference between loading and unloading?

Answer 10

Loading: With repeated sub max loading, small adaptations possible

Unloading (disuse): Drastic changes - decreased water content, cross sectional area, cross links, more floppy

Question 11

What part of the ligament takes the longest to recover after immobilisation?

Answer 11

Insertion site

Question 12

What are the phases of injury and repair for ligaments?

Answer 12

Phase 1: Bleeding, inflammatory process
Phase 2: Scar formation
Phase 3: Matrix remodelling (time/quality varies)

Question 13

How are ligament injuries graded?

Answer 13

Grade 1: Some stretched fibres, clinically stable
Grade 2: Considerable portion of fibres damaged, clinical laxity but definite end point
Grade 3: Complete tear, clinical instability, no firm end point

Question 14

What are the intervention principles for ligaments?

Answer 14

• Determine severity, irritability & nature (SIN)
• Support/protect
• Maintain healthy tissue
• Manage pain/inflamm
• Restore ROM
• Restore strength
• Restore control
• Restore function