This document discusses meniscal injuries of the knee. It begins by describing the anatomy of the menisci, including their location, structure, and attachments in the knee. It then discusses the different types of meniscal tears, including longitudinal, horizontal, radial, and complex tears. The mechanisms of injury and symptoms of meniscal tears are explained. Physical exam maneuvers for diagnosing tears like McMurray's test are outlined. MRI is described as the preferred imaging method to evaluate tears. Finally, treatment options for meniscal tears including non-operative rest and rehabilitation versus surgical repair or removal are presented.

1. Meniscal Injury
Dr Sijan Bhattachan
2nd year resident
Orthopedic & Trauma Surgery
National Academy of Medical Science

2. Anatomy
• Menisci are two fibrocartilagenous
crescents.
Each menisci has
• Two ends-attached to tibia
• Two borders; Outer border is thick,
convex and fixed to fibrous band and
the inner border is thin, concave and
free
• Two surfaces; Upper is concave for
femur and lower is flat for peripheral
two thirds of tibial condyles

3. Medial meniscus
• C shaped (3/5th of ring) with triangular cross
section
• Average width of 9-10 mm; thickness 3-5 mm
• Entire peripheral border is firmly attached to the
medial capsule and through the coronary ligament
to the upper border of the tibia
• Most of the weight is borne on the posterior portion
of meniscus

4. Medial meniscus
• Anterior horn is attached firmly to tibia anterior to the
intercondylar eminence and to the ACL
• Posterior horn is anchored immediately in front of the
attachments of PCL posterior to the intercondylar eminence.

5. Lateral meniscus
• More circular (forming 4/5th of ring) covering upto two thirds of articular
surface of underlying tibial plateau
• Average width 10-12 mm; thickness;4-5 mm
• Anterior horn is attached to the tibia medially in front of the intercondylar
eminence
• Posterior horn inserts into the posterior aspect of intercondylar
eminence and in front of the posterior attachment of medial meniscus

6. • Posterior horn receives anchorage to femur via the ligament of
Wrisberg and ligament of Humphrey and from fascia covering
popliteus muscle
• The tendon of popliteus separates the posterolateral periphery of
lateral meniscus from the joint capsule and lateral collateral
ligament

7. • Lateral meniscus is smaller in diameter, thick in
periphery, wide in body and more mobile
• In contrast medial meniscus is much larger in
diameter, thinner in periphery and narrower in body
and less mobile
• Menisci follow tibial condyles during flexion and
extension but during rotation they follow the femur
and move on tibia

8. Attachment
• Transverse (intermeniscal) ligament; connects medial and lateral meniscus anteriorly
• Coronary ligaments; Connects meniscus peripherally; medial meniscus has less
mobility with more rigid peripheral fixation than lateral meniscus
• Meniscofemoral ligament; Connects posterior horn of lateral meniscus to substance
of PCL
-Two components; Humphrey ligament (anterior) and ligament of wrisberg (posterior)

9. Blood supply
• At birth, menisci are well vascularised throughout their substance; With
ageing through early adulthood, peripheralisation to outer third.
• Medial and lateral inferior genicular arteries supply peripheral 20-30% of
meniscus
• Branches from these vessels give rise to a perimeniscal capillary plexus
within the synovial and capsular tissue.
• The plexus is an arboroid network of vessels that supplies the peripheral
border of meniscus throughout its attachment to the joint capsule
• Central portion receive nutrition through diffusion

10. Composition
• Made of fibroelastic cartilage; Interlacing network of collagen,
proteoglycan and cellular elements; composed of 70% water
• Collagen; 90% type I collagen
• Fibers
-composed of two types of fibers which allow the meniscus to expand
under compressive forces and increase contact area of the joint;
• Radial fibers
• Longitudinal (circumferential)

11. • Circumferential fibers function in hoops to accept
stress without gross deformation or extrusion of
joint
• Radial fibers stablizes the meniscus, preventing
circumferential splits as well as resisting excessive
compressive loads

12. Functions
• Act as a joint filler, compensating for gross incongruity between
femoral and tibial articulating surfaces and prevent capsular and
synovial impingement during flexion extension movements
• Optimize Force transmission across the knee by
-increasing congruency; (increase contact area); Reduces
average contact stress between bones and reduce stress on
articular cartilage.
-shock absorption (meniscus is more elastic than articular
cartilage)

14. • Stability
-Deepens tibial surface and acts as secondary
stabiliser.; Posterior horn of medial meniscus is the
main secondary stabiliser to anterior translation.
-Primary stabilizer in the ACL deficient knee
• Joint lubrication function, helping to distribute
synovial fluid throughout the joint and aiding the
nutrition of articular cartilage

15. Meniscal healing & repair
• Vascular supply to the meniscus determines its
potential for repair.
• Peripheral meniscal blood supply is capable of
producing a reparative response similar to that
observed in other connective tissues because of a
perimeniscal capillary plexus that supplies the
peripheral 10-25 % of menisci.
• Three zones of vascularity- Red, Red- white and
White

16. • After injury within peripheral vascular zone, a fibrin
clot that is rich in inflammatory cells forms.
• Vessels from peri meniscal capillary plexus proliferate
throughout this fibrin scaffold and accompanied by the
proliferation of differentiated mesenchymal cells
• The lesion is eventually filled with cellular
fibrovascular scar tissue that glues the wound edges
together and appears continuous with the adjacent
normal meniscal fibrocartilage

17. Meniscal injury
• Most common indication for knee surgery
• Higher risk in ACL deficient knees
Location;
• Medial tears more common than lateral tears except in
the setting of an acute ACL tear where lateral tears
more common
• Degenerative tears in older patients usually occur in
the posterior horn

18. • The most common location for injury is the posterior
horn of the meniscus and longitudinal tears are the
most common type of injury
• Abnormal mechanical axes in a joint with
incongruites or ligamentous disruptions expose the
menisci to abnormal mechanics and thus can lead
to a greater incidence of injury.

19. Mechanism of injury
• Twisting of loaded joint may trap the menisci between the joint
and tear the meniscus
MEDIAL MENISCUS
• Internal rotation of femur over tibia with the knee in flexion
forces the posterior segment of medial meniscus towards the
centre of joint
• Posterior horn may be trapped in this position by sudden
extension of knee
• This excessive force results in tear of meniscus from its peripheral
attachment and causes a longitudinal splitting of its substance

20. • If this longitudinal tear extends anteriorly beyond
the medial collateral ligament, the inner segment of
meniscus is caught in the intercondylar notch and
cannot return to its former position; thus a classic
bucket handle tear with locking of joint is produced

21. LATERAL MENISCUS
• Vigorous external rotation of femur while the knee is
flexed displace the posterior half of lateral meniscus
towards the center of joint
• During sudden extension of knee, an
anteroposterior distracting force tends to straighten
the cartilage and impose a strain on the medial
concave rim, which tears transversely and obliquely

22. Classification
Based on location (Miller,
Warner and Harner)
• Red zone ( outer third ;
vascularized)
• Red white zone (middle
third)
• White zone (inner third;
avascular)

23. Based on type of tear (O’conner
classification)
• Longitudinal tear
• Horizontal tear
• Oblique tear
• Radial tear
• Variation which include flap tears,
complex tears and degenerative
tears

24. Longitudinal tear most commonly occur as a result
of trauma to a reasonably normal meniscus
• Tear is vertically oriented and may extend
completely through the thickness of meniscus or
may extend only partially.
• Medial side is 3 times more commonly involved
• If tear is near meniscocapsular attachment , it is
referred to as peripheral tear

25. • Complete tear associated with ACL
tears
• Long tears that extend at least two
thirds of the circumference of the
meniscus produce an unstable
fragment that displaces into the
intercondylar notch, referred to as
bucket handle tear

29. Horizontal tears common in older
patients in the posterior horn of medial
meniscus or in the mid portion of lateral
meniscus
• Horizonatal cleavage divides the
meniscus into superior and inferior
leaves resembling a fish mouth

33. Radial tear common in lateral meniscus
and middle third is commonly involved
• Three varieties
-Incomplete (inner edge towards periphery)
-Complete (extends to meniscosynovial rim)
-Parrot beak (longitudinal or oblique tears
added to incomplete or complete radial tear

37. Oblique tears are full thickness
tears running obliquely from the
inner edge out into the body
• If base of tear is posterior, it is
referred to as posterior oblique
tear; if anterior then anterior
oblique tear

38. Flap tears begin as horizontal cleavage tears in the
degenerative tissue of older patient
• Superior or inferior depending on the location of
base of flap

39. Complex tear may contain elements of all the above
types of tears
• More common in chronic meniscal lesions or in
older degenerative menisci
Degenerative tears in older patients
• Marked irregularity and complex tears

40. Presentation
• H/O twisting injury to knee while the joint was flexed
Symptoms
• Pain localizing to medial or lateral side
• Mechanical symptoms (locking and clicking)
• Delayed or intermittent swelling

41. Locking means inability to extend the knee fully.
• This results as displaced segment interpose between the
tibial and femoral condyle preventing full extension.
• Locking usually occurs only with longitudinal tears and is
much more common with bucket-handle tears, usually of
medial meniscus
• Locking mustnot be considered pathognomonic of bucket-
handle tear since an intraarticular tumor, osteocartilaginous
loose body and other conditions can cause locking

42. • False locking occurs most often soon after an injury
in which haemorrhage around the posterior part of
capsule or collateral ligament with associated
hamstring spasm prevents complete extension of
knee.
• Aspiration and short period of rest until the reaction
has partially subsided usually will differentiate
locking from false locking

43. • If a patient does not have locking, the diagnosis of a
torn meniscus is more difficult.
• Patient typically gives h/o several episodes of
trouble referable to knee, often resulting in effusion
and a brief period of disability.
• A sensation of giving way or snaps , clicks, catches
or jerks in the knee may be described.

44. • Sensation of giving way; Noticed on turning around
suddenly, walking on uneven ground and often
associated with a feeling of subluxation or “the joint
jumping out of place”
• Sensation of giving way can also occur in other
disturbances of knee especially loose bodies,
chondromalacia of patella, instability of joint
resulting from injury to ligaments or from weakness
of the supporting musculature, especially
quadriceps.

45. O/E;
• Joint line tenderness is the most sensitive physical examination finding
• Effusion (Repeated displacement of torn portion can produce chronic synovitis
with an effusion of non bloody nature)
• Atrophy of quadriceps suggests recurring disability of knee
Provocative tests; attempts to locate and to reproduce crepitation that results as
the knee is manipulated.
• McMurray’s test
• Thessaly test
• Apley compression test

46. McMurray test
• With patient supine and knee is acutely
and forcibly flexed, examiner can check
the medial meniscus by palpating the
posteromedial margin of the joint with
one hand while grasping the foot with the
other hand
• Keeping knee completely flexed, the leg
is externally rotated as far as possible
and then the knee is slowly extended.
• As the femur passes over a tear in the
meniscus, a click may be heard or felt;
patient complains of pain

47. • For lateral meniscus, palpate posterolateral margin and
internally rotate the leg
• A click produced by the McMurray test usually is caused by a
posterior peripheral tear of the meniscus and occurs between
complete flexion of knee and 90 degrees.
• Popping which occurs with greater degree of extension when it
is definitely localized to the joint line, suggest a tear of middle
and anterior portion of the meniscus.
• Thus , it helps to locate the lesion as well.
• Sensitivity 70% and specificity 71%

48. Apley’s grinding test
• With patient prone, knee flexed to 90 degrees and anterior thigh is fixed
against the examining table.
• Foot and leg are then pulled upward to distract the joint and rotated to
place rotational strain on ligaments; Painful if ligaments have been torn
• Next, foot and leg pressed downward and rotated as the joint is slowly
flexed and extended; Popping and pain localised to joint line may be noted
when a meniscus is torn.
• Sensitivity 60% and specificity 70%

49. Thessaly test
• Examiner supports the patient by holding his
outstretched hands while the patient stands
flatfooted on the floor.
• The patient then rotates his or her knee and body,
internally and externally, three times with the knee
in slight flexion (5 degrees); Also in 20 degrees.
• Patient with suspected meniscal tears experience
medial or lateral joint line discomfort and may
have a sense of locking or catching
• Diagnostic accuracy rates of 95%.

50. Squat test
• Several repetitions of a full squat with the feet and
legs alternately fully internally and externally
rotated.
• Pain usually is produced on either the medial or
lateral side of knee, corresponding to the side of
torn meniscus
• Pain in internally rotated position suggests injury to
lateral meniscus and that in externally rotated
position suggest injury to medial meniscus

51. Steinmann’s test
• Patient sits with leg bent over
the table about 90 degrees
• To assess the MM tear, foot is
externally rotated which
produces some discomfort.

52. Imaging
Radiographs
• Anteroposterior, lateral and intecondylar notch
views with a tangential view of the inferior surface of
patella should be routine.
• Essential to exclude osteocartilaginous loose
bodies, osteochondritis dissecans and other
pathological processes that can mimic torn
meniscus.

53. MRI
• With 98% accuracy for medial meniscal tears and 90% for lateral
meniscal tears, MRI is the modality of choice when a meniscal
tear is suspected, with sagittal images being most sensitive.
• Three basic MRI characteristics/ criteria of meniscal tears;
-High intrameniscal signal extending to at least one articular surface
- Which should be seen in at least two slices.
-Distortion of normal meniscal morphology if no prior surgery

54. Grading
• Grade I; Torn meniscus has focal increased signal
• Grade II; Pronounced and frequently linear signal that does not
break the surface of meniscus
• Grade III; signal that traverses through the meniscal surface
• Grade IV; Extension of tear through both tibial and femoral surfaces
of meniscus
• Grade I and II appear normal on arthroscopic evaluation

55. • MRI grade III signal is indicative of a tear; linear
high signal that extends to either superior or inferior
surface of meniscus
• Parameniscal cyst indicates the presence of a
meniscal tear

59. • Double PCL sign; Seen in sagittal image when a
bucket handle tear of meniscus flips to intercondylar
recess and comes to lie anteroinferior to PCL

60. Arthrography
• Invasive procedure
• Air and opaque contrast material such as diatriziate
sodium injected into the joint.
• Multiple roentgenographic views are made by
rotating the joint and bringing all portion of medial
and lateral menisci into profile
• Accuracy 95% in MM and 85% in LM

61. Arthroscopy
• Diagnostic as well as therapeutic procedure
• Diagnostic accuracy of 98% for MM and 90% for LM

62. Treatment
• Non Operative
Indications
• Incomplete meniscal tear or small (5 mm) stable
peripheral tear with no pathological condition
• Tears associated with ligamentous instabilities if
patient defers ligament reconstruction or
contraindicated

63. Non operative
• Rest, Ice, Compression and Elevation
• NSAIDs
• Groin to ankle cylindrical cast for 4-6 week
• Isometric exercise program

64. • At 4-6 weeks, cast removed and rehabilitative program
intensified.
• Most important aspect of nonoperative treatment is
restoration of power of muscles around the injured knee
to a level comparable with that of the opposite knee
• If symptoms recur after a period of nonoperative
treatment, surgical treatment may be necessary

65. Operative
• Meniscectomy
-Arthrotomy
-Arthroscopy
• Meniscal repair
-Arthrotomy
-Arthroscopy
• Meniscal transplantation (autografts, allografts or prosthetic
scaffolds)

66. Meniscectomy
Based on amount of meniscal tissue to be removed, O
Conner classified;
• Partial meniscectomy; Only the loose unstable fragment
excised; stable peripheral rim preserved.
• Subtotal meniscectomy; Excision of portion of peripheral
rim; Most of the anterior horn and portion of middle 3rd of
meniscus are not resected
• Total meniscectomy; When meniscus is detached from its
peripheral meniscosynovial attachment and intrameniscal
damage and tears are extensive

68. Partial menisectomy
• Indications
-Tears not amenable to repair (complex, degenerative,
radial tear patterns)
-repair failure more than 2 times
• Standard arthroscopic approach
• Post op; Early active ROM

69. Outcomes
• >80% satisfactory function at minimum follow up
• 50% have Fairbanks radiographic changes
• Predictors of success;
-age<40 yrs
-normal alignment
-minimal or no arthritis
-single tear

70. Arthroscopic meniscectomy
General principles of Arthroscopic meniscectomy
• Partial meniscectomy is always preferable to subtotal or
total meniscectomy
• To determine accurately the type of meniscectomy
required, the meniscal lesion must be carefully probed
and classified
• Objective is to remove the torn, mobile meniscal
fragment and contour the peripheral rim, leaving a
balanced, stable rim of meniscal tissue.

71. • Excision of the pathological tissue can be done either
with en bloc resection of the mobile fragment or by
morcellization of the fragments and subsequent removal.
• When the tear has been removed, the remaining
peripheral rim must be carefully probed to ensure that
there are no additional tears and that the rim is balanced
and stable
• Then joint should be thoroughly ravaged and suctioned
to remove any small meniscal fragments or debris that
may have dropped into the joint as a result of resection

72. Bucket handle tear
• Common tear usually occuring in young patients as
a result of significant trauma and frequently
associated with an ACL injury and medial side is
more commonly involved
• Extend at least two thirds of the circumference of
meniscus producing an unstable fragment that locks
into the joint by displacing towards the notch

73. • Patient with bucket handle tear who may be a candidate for meniscal
repair should have this possibility discussed before arthroscopy.
• Common criteria for meniscal repair include
-Vertical longitudinal tear more than 1 cm in length located within the
vascular zone
-Tear that is unstable and displaceable into the joint
-An informed and cooperative patient who is active and younger than 40
yrs old
-Knee that is stable or would be stabilised with ligamentous
reconstruction simultaneosly

74. • Only 10-15 % of meniscal tears can be repaired that
most such repairs are done in association with ACL
reconstruction.
• Bucket handle tears that cannot be repaired can be
treated with partial meniscectomy.
• Either two portal or three portal technique can be
used

75. Two portal technique for
bucket handle tear
• Displaced bucket handle tear of lateral meniscus is
probed

76. • After reduction of displaced bucket handle tear,
posterior attachment is partially released with
scissors

77. • Anterior attachment is released with scissors

78. • Tenuous remaining posterior attachment is avulsed
with grasper and extracted.

79. Post meniscectomy rehab
protocol
• A compression bandage is applied to the knee and immobilised for
5-7 days
• Ice is applied over knee and limb is elevated for 24-48 hours
postoperatively.
• Quadriceps exercises are started on 2nd day onwards; SLR
isometric quadriceps exercises are carried out on every hour when
the patient is awake.
• When the good muscular control is achieved, patient is allowed to
walk with crutches and with partial weight bearing
• Sutures removed at 2 weeks and gentle resistive exercises begun.

80. Complications after meniscectomy
• PostOp heamarthrosis
• Chronic synovitis
• Synovial fistula
• painful neuromas of the branches of infra patellar portion of saphanous nerve
• Thrombophlebitis
• Infection
• Reflex sympathetic dystrophy
• Retained meniscal fragment

81. • Late degenerative changes within the joint
Fairbank described three changes
• Narrowing of joint space
• Flattening of the peripheral half of the articular
surface
• Development of anteroposterior ridge that projects
distally from the margin of femoral condyle

82. Meniscal repair
• Only 10-15% of tears can be repaired and these are usually
associated with ACL injuries.
Consists of 3 important steps
• Appropriate patient selection - should have documented tear
that is able to heal. (single longitudinal tear in outer third)
• Tear debridement and local synovial, meniscal and capsular
ablation to stimulate a proliferative fibroblastic healing
response.
• Suture placement to reduce and stabilize the meniscus

83. Criteria
• Peripheral in the red red zone ( within 3 mm of
periphery)
-lower rim width has more ability of healing; Rim width
is the distance from the tear to the peripheral
meniscocapsular junction)
• Vertical and longitudinal tear ( Horizontal,Oblique,
Radial, degenerative, complex tears are excised)

84. • Age less than 50 yrs
• Acute tears less than 8 weeks have better healing
potential
• ACL deficiency must also be corrected
simultaneously to prevent instability

85. Approach
• Inside out technique
• All inside technique
• Outside in technique
• open repair

87. • Vertical mattress sutures are strongest because
they capture circumferential fibres

88. After treatment
• Knee is placed in a hinged brace and immediate
range of motion from 0-90 degree is permitted.
• Touchdown weight bearing is permitted immediately
• Full weight bearing is permitted at 6 weeks when the
brace and crutches are discarded
• No sports allowed for 3 months

89. Outcomes
• 70-95% successful
• Highest success when done with concomitant ACL
reconstruction
• Poor results with untreated ACL deficiency

91. Meniscal replacement
• Aim is to prevent degenerative changes, in post
meniscectomy patients
• Indications
-Age <40 yrs who had previous meniscectomy
-Symptoms localized to tibiofemoral compartment
-No advanced arthrosis

94. Compliations
• Saphenous neuropathy
• Arthrofibrosis
• Sterile effusion
• Peroneal neuropathy
• Infection

95. References
• Apley’s system of orthopaedics and fractures, 9th
edition.
• Campbell operative orthopaedics,12th edition.
• orthobullets.com
• Internet sources