Lecture 6 - Ligament and Joint Injuries

Question 1

What is the structure of a ligament?

Answer 1

Dense bands of collagen tissue
vary is size, shape, orientation, location

Question 2

What are the functions of ligaments?

Answer 2

• Passive stabilization of the joints by connecting one bone to another
• important proprioceptive function

Question 3

How do ligaments respond to injury?

Answer 3

• healing follows the constant pattern
• ligament scars have weaker tensile strength and poor viscoelastic properties (scar tissue fibres are highly disorganized)
• ligament injury leads to decreased proprioception

Question 4

What percentage of change in length will cause the collagen fibres to start to rupture?

Answer 4

4%

Question 5

What are the 3 types of ligaments? Which have the best healing potential?

Answer 5

• intra-articular (poor healing)
• extra-articular (good healing)
• capsular (thickening of capsule, good healing)

Question 6

How do ligaments adapt to training? And by how much can they increase strength?

Answer 6

• they adapt slowly to increased loading, but will weaken very quickly as a result of immobilization
• they adapt by increasing their cross-sectional area
• can increase strength by 10-20% using systematic training

Question 7

What does joint stability depend on?

Answer 7

The interaction between the passive (non-contractile connective tissues), active (muscle + tendon) and neural (CNS + nerve) subsystems

Question 8

What is a common injury mechanism for ACL injuries?

Answer 8

Direction changes, usually occurs 30-50 milliseconds after initial contact, valgus force

Question 9

Can we treat ACL injuries conservitavely?

Answer 9

Yes, but does sometimes require ACL reconstruction

Question 10

Are ACL injuries more common in men or women?

Answer 10

Women

Question 11

What are some prevention strategies for ACL injuries?

Answer 11

Modifiable risk factors:
- weak hip abductors and external rotators (strengthen)
- increased knee abduction moments during cutting and landing
- teach/use proper technique
- knee control training program

Question 12

What is the difference between subluxation and dislocation?

Answer 12

Subluxation, there is still some contact between joint surfaces. Dislocation, no contact between joint surfaces

Question 13

What is the mechanism for shoulder dislocation/subluxation?

Answer 13

direct blow to the shoulder, usually from posterior side

landing on outstretched arm

Question 14

Can we treat shoulder subluxation/dislocation conservatively?

Answer 14

We can, but high recurrence rate so will do surgery in high risk population. Rehab is critical to long term function

Question 15

How can we prevent shoulder subluxation/dislocation?

Answer 15

-proper technique
- strength training

Question 16

What does it mean when we say ligaments can creep?

Answer 16

They can lengthen (slow stretching of ligaments)