1) Meniscus injuries are among the most common orthopedic injuries seen in practice, with an incidence of 61 cases per 100,000 people per year. Arthroscopic partial meniscectomy is one of the most common orthopedic procedures. 2) Meniscal tears can be classified based on location and pattern. Common types include bucket handle tears, longitudinal vertical tears, radial tears, and root tears. MRI is the gold standard for diagnosis. 3) Treatment depends on the type and stability of the tear. Unstable tears may be treated with meniscectomy or repair, while stable tears can be managed non-surgically with physical therapy. The goal of surgical treatment is to deb

1. Ian Rice MD
Meniscus Injuries

2. How far we haven’t come
• “…It is, however, a clinical
fact that one of the semilunar
cartilage, usually the internal
one, does occasionally
become loosened from its
attachments; and, in
consequence, this body is
liable to be displaced either
forwards or backwards, and
so to interfere with the proper
movements of the knee-
joint…”
1838 - 1907

3. • Among most common injuries seen in orthopedic practice
• 61 cases per 100,000 per year
• Arthroscopic partial menisectomy one of the most common
orthopedic procedures
Epidemiology

4. Pathoanatomy
• Overview
– Crescent shaped and have
triangular cross section
– Fibers have circumferential
orientation
– Anterior and posterior root
attachments prevent extrusion
– Lateral covers 84% of the
condylar surface, 12mm wide, 3-
5mm thick
– Medial covers 64%, 10mm wide,
3-5mm thick

5. • Vascularity
– Genicular arteries
– 50% vascularized at birth
– 10-25% in adults
– Makes healing very difficult
– 3 vascular zones
• Red-red
• Red-white
• White-white
Pathoanatomy

6. • Collagen Organization
– Circumferential fibers
– Radial Fibers
– Fine superficial layer
around outside
Pathoanatomy

7. • Load Sharing
– Increases contact area between femur and tibia
– Decreases contact stress on articular cartilage
• Increases congruity
• Provides stability
• Aids in lubrication
Meniscal function

8. • In extension, 50% of the load is absorbed
• At 90 flexion, 90% load-sharing
• Beyond 90, forces predominate through posterior horns
Biomechanics

9. – Meniscal excursion with
knee flexion
• 11.2 mm excursion of
lateral meniscus
• 5.1 mm excursion of
medial meniscus
– Capsule
– Deep MCL
– Coronary ligament
Meniscal Excursion

10. • Complete removal of meniscus
results in 2-3X increase in
contact stress
• Removal of inner 1/3 = 10%
reduction in contact area and
65% increase in stress
• Increase loss of meniscal tissue
= increase contact stress
• Medial meniscal root tears have
pressures similar to complete
meniscectomy
Biomechanics

11. • History
– Twisting injury with change in direction in younger patients
– Squatting or falling in older patients
– Acute tear usually has insidious swelling
– Joint line location
– Mechanical complaints
Evaluation

12. • Small effusion
• Joint Line Tenderness
• McMurray
• Apley
• Thessaly
• ROM generally normal
– Bucket handle block
– Tight due to effusion
Physical Exam

13. McMurray

14. McMurray

15. Apley’s Compression Test

16. Thessaly Test

17. • Plain films to assess for bony
injury and OA
• MRI is the gold standard of
diagnosis
Imaging

18. • Typically seen in younger patients
• High association with ACL tears
• 90% of LVT in MM and 83% in LM are associated with ACL tears
Longitudinal Vertical Tears

21. • This is a LVT with central
margination
• Most frequent type of
displaced tear
• Double PCL
• Double Anterior Horn
• Absent Bow
Bucket Handle Tears

23. • Involves the free edge and propagates peripherally
• Usually degenerative
• Older patients
Horizontal Tears

26. • Also involve free edge, but path is perpendicular to long axis
• Drastically affect ability to resist hoop stresses
• Deeper the tear, the more drastic the biomechanical consequences
Radial Tears

27. Radial Tears

28. Radial Tear

29. • AKA vertical flap tear
• Starts as a radial tear
• Propagates as a longitudinal
Parrot Beak Tears

30. Parrot Beak Tear

31. Root Tears

32. • Non-surgical
– Stable, longitudinal <10mm with
<3-5mm displacement
– Degenerative tears with
concomitant OA
– <3mm radial tears
– Stable partial tears
Treatment

33. • Indications
– Radial
– Flap
– Horizontal
– Complex
– White-white tears
Meniscectomy

34. • Goal is to debride tear and leave
stable rim
• Preservation is ideal
• 80% satisfactory function at 5 yrs
• Lateral debridement = faster
degeneration
Meniscectomy

35. • Predictors of Positive Result
– < 40yo
– Normal alignment
– Minimal arthritis at initial scope
– Single fragment tear
Meniscectomy

36. • Relative Contraindications
– Advanced OA
– Complex tears
– Poor tissue quality
– ACL deficiency
Surgical Repair

37. Open Repair
• Rarely used
• Numerous studies have proven reduced surgical morbidity
with arthroscopic repair
• Reserved for peripheral tears in the posterior horn

38. Inside-out Repair
• Suture passed on either side
of tear with needle cannula
• Suture is brought out of
capsule
• A small skin incision is made
• Suture is tied down to capsule
• Posterior Horn Repairs

39. • Sutures passed through the
meniscus from the outside
• Eliminates need for larger
incision
• Generally suited for anterior
repair
• Studies have shown similar
results with both techniques
Outside-In Repair

40. • All-inside repair devices were
developed to reduce surgical
time, prevent complications
resulting from external
approaches, and allow access to
tears of the posterior horn
• Fourth-generation repair devices
allow placement of sutures in the
meniscus without the aid of an
external incision or a suture
fixator system
All Inside

41. • Self-adjusting, with the anchor
located behind the capsule and
with a sliding knot that can be
tensioned appropriately by the
surgeon
• Mechanical studies show
comparable strength to outside-
in sutures
All Inside

45. Outcomes
• Success rates for all techniques reported 70-95%
• Second-look scopes show lower success rates of 45-91%
• Ligamentous laxity decreases success rate to 30-70%
• 90% success reported in conjunction with ACL repair

46. • Failure to heal
• Stiffness
• Articular surface damage
• NV structure damage
Complications

47. Transplantation
• Indications:
– Recurrent pain after partial or total debridement
– symptomatic with ADLs
– <50yo
• Contraindications:
– Malalignment
– Laxity
– Inflammatory arthritis
– Advanced OA

48. Outcomes
• Widely varying reports of success (Country differences)
• Subjective improvement in tibiofemoral pain
• No clear long-term benefit in preventing OA has been
established
• Grafts seem to do better when placed with a bone block
• Preserving some peripheral rim helps to avoid extrusion
• Variety of meniscal scaffold options being investigated in
animals

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