1. PTP 521 Musculoskeletal Disorders and Dysfunctions
Ligaments
PTP 521
Musculoskeletal Disorders and Dysfunctions

2. I. Ligaments Latin: Ligare: to tie or bind Named:
Bones in which they insert
Shape
Relationship to joints
Relationship to each other

3. Ligaments
1. Connect two bones together 2. Stabilize joints 3. Connective tissue structure 4. Shared function of restraint 5. Proprioceptor for the joint

4. Histological Composition of Ligaments
2/3 water
Contributes to cellular function
Viscoelastic behavior
1/3 solid
Collagen (up to 27 types have been identified in ligaments, generally considered to be one of 6 types
Proteoglycans – control collagen fibrillogenesis by controlling fibril diameter and the rate of fibril formation
Elastin: <2% of most ligaments

5. Influence of Hormones on Ligaments
Some ligaments have receptors for hormones (estrogen, progesterone, and androgens)
Ligament function could be regulated by hormones
Might be gender-specific of regulation

6. Evidence to Support Hormonal Influence:
During pregnancy, hormone relaxin is released to cause laxity in ligaments
Women more likely to have benign joint hypermobility syndrome
Ligamentous laxity during menstrual cycle – not clearly defined

7. Effects of Immobilization
Load Deprivation: rapid deterioration in biochemical and mechanical properties
Ligaments are strain-rate sensitive
Stronger and stiffer at higher loading rates

8. Decrease in ligament mass causes net loss in ligament strength and stiffness
Shift in ligament cell metabolism from a building or steady state to a destructive state
Few weeks of immobility: ligament matrix quantity decreases
Bone will resorb causing weakness at insertional sites

9. Immobilization greater than 6-9 weeks can result in as much as a 50% reduction in strength

10. Effects of Exercise
Response to exercise: increase strength and stiffness (minimally)
Potential to increase ligament strength and stiffness no more than 10-20%
Effects of exercise may be ligament specific

11. Ligament Injuries One of the most common injuries to joint
MOI: Falls, twisting, getting hit
Knee in particular is susceptible
25-40%

12. Injury to Ligaments Sprain a. Definition: disruptions of
fibers of a ligament
b. Key point
Caused by a force that stretches fibers beyond elastic limits

13. Mechanisms of Injury Joint Dependent Extrinsic Load applied to joint
Ligaments parts that are the best to restrain in that position are loaded the most
Deform past elastic limit
Fail

14. Force required and amount of instability occurring are dependent upon
1) size of ligament
2) age of person
3) position of joint when force occurs

15. Evaluate immediately after an injury
Failure occurs at insertion, body of ligament or bone interface (avulsion)
Children
Adults
Evaluate immediately after an injury

16. Unstable only in the position of injury.
True of partial ligament tears only
MRI, stress radiographs and arthrograms are all imaging studies to determine the existence of a ligament sprain

17. Avulsion Fractures Force: tensile loading of tissue
Causes insertion site to pull away from bone taking a part of bone with it

18. Enthesitis Definition: inflammation of insertion of ligament or tendon
Extra-articular
Younger child may be called apophysitis

19. Ligament Sprains Classification of Sprains: Number of fibers disrupted
Instability of the joint involved

20. Grade I: mild or first degree sprain
Signs: ROM limited in one direction only
Increase in pain during PROM and AROM – when ligament is stressed
Limited bruising
Symptoms: localized tenderness over the injury area, pain

22. Grade II: moderate or second degree sprain
Symptoms: more diffusely tender
Increase in pain
Instability with weight bearing and with movement that would stress the ligament
Generally parts of several ligaments are injured with a second degree
Signs: clinical evidence of instability
Stress testing gives slight laxity but not complete functional instability
Ecchymosis
Decrease in ROM, painful, swelling restricts movement
Edema

23. Grade III: severe or third degree sprain
Signs: significant laxity is seen, abnormal increase in ROM
Severe swelling
Ecchymosis or hemarthrosis
Structural, functional instability
Symptoms: may be less painful than a grade II sprain
May also have second degree sprains in other ligaments

24. Joint Instability
Stress testing: compare the injured and the non-injured side 0 instability: No difference between injured and non-injured side 1+ instability: difference is less than 0.5 cm 2+ instability: difference is between 0.5cm and 1cm 3+ instability: difference is greater than 1cm

25. Ligamentous Healing Phase 1: Inflammation, occurs within 72 hours.
Inflammatory response
Immediate pain and bleeding
Extra-articular ligaments: bleeding outside joint cavity
Intra-articular ligaments: bleeding within joint cavity

26. Phase 2:
Repair/Regeneration: hours after injury and lasts up to 6 weeks
Production of scar matrix, viscous material becomes less viscous as days go on

27. Healing Failure:
a. failure to reconnect appropriate locations on bones
b. failure to produce enough scar tissue
c. failure to produce the correct type of tissue

28. Phase 3: Remodeling: 6 weeks to 12 or more months to complete
Over time, becomes more ligamentous, some differences exist in both composition and architecture of the ligament.

29. Surgical Repair Guidelines
1. Patient is high risk for instability in the future
2. Age of patient
3. Type of ligament sprain that occurs
4. Associated lesions, degree of laxity

30. Types of Surgeries Repair: reattachment of torn ends of a ligament
Reconstruction: replacement of original ligament with a graft
Autograph
Allograph