Meniscal Pathology

Mr. Abdul Wahab

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

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

MedialLateral

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

Biomechanics

6/29/2013 6

• Limited contact

area

• High contact

stress

• More contact

area

• Low contact

stress

Meniscectomy Meniscus intact

Load

Distribution

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

Biomechanics

Blood Supply

• Periphery receives blood supply (20-40%)

• Remaining portion nourishes from synovial

fluid by diffusion

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

Normal meniscus

Small meniscus

Truncated free edge

Displaced meniscal fragment

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

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

Knee

Examination• Look (gait, muscle atrophy, swelling, bruise)

• Feel (joint line tenderness, effusion, cyst)

• Move (pain on extreme movement,

block, check ACL, LCL, MCL)

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

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

Patient sits with the leg

flexed over the table about

90 degree.

Rotate tibia internally and

externally

Joint line pain confirms test

positive

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

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

Types of meniscal tears according to plane of

cleavage

Meniscal

tears

Vertical Horizontal

Longitudinal Radial

Horizontal tear

Is parallel to the tibial plateau and divide the

meniscus into upper and lower segments.

Horizontal tear

Longitudinal vertical tear

Perpendicular to the tibial plateau & parallel to

the long axis of the meniscus.

Longitudinal vertical tear

Peripheral longitudinal tear

Radial tear

is perpendicular to the tibial plateau &

perpendicular to the long axis of the meniscus.

Body radial tear

Full thickness body radial tear

Posterior horn radial tear

Displaced meniscal tears

Displaced

meniscal tears

Vertical Horizontal tear

(Flap tear)

Displaced

Longitudinal tear

(bucket handle tear)

Displaced

Radial tear

(Parrot beak tear)

Displaced Meniscal Tears

Flap tear

Flap tear

Trimmed meniscus

Bucket handle tear(Displaced Longitudinal Tear)

Bucket handle tear

Reduced bucket handle tear

Boe-ties sign (normal meniscus

Flipped variant of bucket handle tear

Meniscal extrusion

Parrot beak tear (radial oblique tear)

Management

Non Surgical

Surgical

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

Surgical Management

1. Meniscectomy

By arthrotomy

By arthroscopy

2. Meniscal repair

By arthrotomy

By arthroscopy

3. Meniscal transplantation

Autografts

Allograft

Prosthetic scaffolds

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

Open technique

Inside out technique

All inside technique

Repair

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