This document discusses the anatomy, biomechanics, and pathology of the meniscus in the knee. It begins by describing the structure and functions of the meniscus, including its role in load distribution, shock absorption, and joint stability. It then covers the different types of meniscal tears, categorized by their orientation (horizontal, longitudinal, radial). Imaging techniques for identifying meniscal tears are discussed, along with clinical exams. Finally, the document outlines treatment approaches, including non-surgical management and surgical options like meniscectomy, repair, and transplantation.

1. Meniscal Pathology
Mr. Abdul Wahab

2. Anatomy of the meniscus
 Fibrocartilage C-shaped disc
 Mesenchymal tissue - appear
in 8 -10 weeks of gestation
 Highly cellular and vascular
initially
 Type-1 collagen with 75% of
water
 Fibers orientation

3.  Posterior horn thicker & wider than the
anterior horn in medial meniscus
 Lateral meniscus more mobile
 Not attached with Tibia at Popliteal hiatus
Insertional Ligaments
1-Transverse Meniscal Ligament
Connects both menisci anteriorly
2- Coronary (meniscotibial) ligaments
Connect medial meniscus to Tibia anterolaterally
3-Meniscofemoral ligament of Wrisberg (70%)
Passes from posterior horn of lateral meniscus to medial femoral
condyle posterior to PCL
4-Meniscofemoral ligament of Humphrey
Passes from posterior horn of lateral meniscus to medial
femoral condyle anterior to PCL
Lateral Medial

5. Biomechanical Functions
 Load distribution
 Shock absorption
 Joint stability
 Joint lubrication
 Nutrition of articular cartilage
 Helps knee locking in extension
 Reduce friction between Tibia and Fibula
Chock block

6. Biomechanics
Meniscectomy Meniscus intact
• Limited contact
area
• High contact
stress
6/29/2013 6
Load
Distribution
• More contact
area
• Low contact
stress

7. BIOMECHANICS OF MENISCUS
 The contact force of the menisci
on the femur helps guide the femur
anteriorly during flexion
 The reaction force of the femur
on the menisci deforms the
menisci posteriorly on the tibial
plateau.
 Continuity of peripheral meniscal
rim is very important for load
bearing
 Partial meniscectomy still preserve
this function
 A radial tear or total menisectomy
massively increase contact stress
and cause OA changes
Femoral
Condyle
Movement

8. Biomechanics

9. Blood Supply
• Periphery receives blood supply (20-40%)
• Remaining portion nourishes from synovial
fluid by diffusion

10. Mechanism of injury
 Body rotates with foot
on ground and knee
partially flexed
 Repetitive squatting
cause medial meniscal
injury
 Trivial injury required
in arthritic knee
 Pivoting sports i.e.
soccer, rugby, net ball,
basket ball

11. Normal meniscus
Small meniscus
Truncated free edge
Displaced meniscal fragment

12. Unhappy Triad
Also called
 Terrible triad
 O’Donoghue’s triad
 Blown knee
 Knee banged on lateral side in semi flexion with foot stable on ground
Injury to
1. Medical collateral ligament
2. ACL
3. Lateral/medial Meniscus

13. Signs & symptoms
Not all meniscal tears are symptomatic
 Swelling
 Pain and tenderness along joint line - medial or lateral
 Pain worse on squatting, kneeling or pivoting
 Locking of the knee
 Giving way, snaps, clicks, clunks, catches in knee.
 Atrophy of quadriceps
 Instability of joint
 Elastic block at terminal extension
 Springy end feel

14. Knee
Examination
• Look (gait, muscle atrophy, swelling, bruise)
• Feel (joint line tenderness, effusion, cyst)
• Move (pain on extreme movement,
block, check ACL, LCL, MCL)

15.  Prone position
 Knee flexed to 90 degree and
thigh fixed to the examination
table
 compression and rotating
tibial plateau on femoral
condyles
 Joint line pain on rotation

16. Thessaly Test
 Hold patient’s outstretched hands for support
 Ask the patient to stand on normal leg first and ask
to rotate body with knee flexed to 20 degree
 Now, ask the patient to stand on affected leg
bend knee to 20 degree and rotate body 3 times
internally and externally
 Test Positive if symptoms appear

17.  Patient sits with the leg
flexed over the table about
90 degree.
 Rotate tibia internally and
externally
 Joint line pain confirms test
positive

18. Imaging
Plain Radiographs
 Not helpful in meniscal injury
 Rule out other bony or joint pathology
Arthrography
 Invasive
 Accuracy rate 60% - 90%
 Largely replaced by MRI
Tibial tunnel enlargement – ACL injury

19. MRI
 Non invasive, no ionising radiation
 Differentiate between repairable and
non-repairable tears
 Average sensitivity:
95% medial and 81% in lateral
Average specificity
88% medial and 95% lateral
 Meniscus looks dark due low signal
(high water content).
 Picks associated injuries (ACL)
 Surgery can be planed ahead

20. Types of meniscal tears according to plane of
cleavage
Meniscal
tears
Vertical Horizontal
Longitudinal Radial

21. Horizontal tear
 Is parallel to the tibial plateau and divide the
meniscus into upper and lower segments.

22. Horizontal tear

23. Longitudinal vertical tear
Perpendicular to the tibial plateau & parallel to
the long axis of the meniscus.

24. Longitudinal vertical tear

25. Peripheral longitudinal tear

26. Radial tear
 is perpendicular to the tibial plateau &
perpendicular to the long axis of the meniscus.

27. Body radial tear

28. Full thickness body radial tear

29. Posterior horn radial tear

30. Displaced meniscal tears

31. Displaced Meniscal Tears
Displaced
meniscal tears
Vertical Horizontal tear
(Flap tear)
Displaced
Longitudinal tear
(bucket handle tear)
Displaced
Radial tear
(Parrot beak tear)

32. Flap tear

33. Flap tear
Trimmed meniscus

34. Bucket handle tear
(Displaced Longitudinal Tear)

35. Bucket handle tear
Reduced bucket handle tear
Boe-ties sign (normal meniscus

36. Flipped variant of bucket handle tear

37. Meniscal extrusion

38. Parrot beak tear (radial oblique tear)

39. Management
 Non Surgical
 Surgical

40. Non surgical management
 Incomplete tear
 Small (5mm) peripheral stable tear
 Tears associated with ligamentous injuries (where reconstruction
deferred or contraindicated)
•R-rest
I-ice
C-compression
E-elevation
•NSAIDS
•Physio
•Immobilisation

41. Surgical Management
1. Meniscectomy
 By arthrotomy
 By arthroscopy
2. Meniscal repair
 By arthrotomy
 By arthroscopy
3. Meniscal transplantation
 Autografts
 Allograft
 Prosthetic scaffolds

42. Meniscal repair
 Arnoczky and Warren -
peripheral zone is repairable
 Canine model - fibrin clot
formation in red-red zone
-- scar formation in 10 weeks
 Superficial zone cells –
progenitor cells
Factors affecting repair
 Location of tear
 Location of tear
 ACL reconstruction
 Age of tear
 Age of patient

43. Repair
Open technique
Inside out technique
All inside technique

44. All inside repair (arthroscopic)
 Arrows
 Darts
 Cinch
• Bioabsorbable
material
• Very hard
• Can break
• Can migrate
• Device rubbing can
cause cartilage defect
 Second generation delivery system
 2 plastic anchors connected with sutures passed by
needle deliver system
 Knots tightened outside