Meniscal tears

Meniscal function is essential to normal function of the knee joint

When the menisci is removed the joint contact area is reduced by 40% the contact area is 2.5 times greater when the menisci are present.

In 1948 Fairbank first reported the roentenographic changes after meniscectomy

In 1970 DeHaven began to perform the open meniscal repair through posterior arthrotomy, usually in conjunction with ligament reconstruction.

Ikeuchi performed the first meniscectomy in Tokyo n 1979.

In 1980 Hening performed the first meniscectomy in the United States.

O’Connor is the Pioneer of arthroscopic repair.

Menisci are two fibrocartilagenous crescents

They try to deepen the articular surfaces of the condyles of the tibia, partially divide the joint cavity into upper and lower compartments.

Each menisci has Two ends- attached to the tibia. Two borders- the outer border is

thick, convex and fixed to the fibrous band; the inner border is thin concave and free

Two surfaces- the upper surface is concave for femur; the lower surface is flat for peripheral two thirds of the tibial condyles.

It is a C shaped structure forming 3/5 of the ring asymmetrically larger posteriorly than anteriorly.

The anterior horn is attached to the tibia anterior to the intercondylar eminence and to the anterior cruciate ligament.

The posterior horn is anchored immediately in front of the attachment of posterior cruciate ligament posterior to the intercondylar eminence.

Its entire peripheral border is attached to the medial capsule and through the coronary ligament to the upper border of tibia.

Most of the weight is borne on the posterior portion of the meniscus.

It is circular forming 4/5 the of the ring with symmetrical anterior and posterior horn.

The anterior horn is attached to the tibia in front of the intercondylar eminence.

The posterior horn is attached to posterior aspect of the intercondylar eminence in front of posterior attachment of the medial meniscus.

The posterior horn receives anchorage to the femur via the ligament of Wrisberg and ligament of Humphrey and from fascia covering the popliteus muscle.

The tendon of the popliteus separates the posteriolateral periphery of the lateral meniscus from the joint capsule and fibular collateral ligament.

The lateral meniscus is smaller in diameter, thick in periphery, wide in body and more mobile.

In contrast the medial meniscus is much larger in diameter is thinner in the

periphery, narrower in body and less mobile. The menisci follow the tibial condyles

during flexion and extension, but during rotation they follow the femur and move on the tibia.

Menisci are composed of dense, tightly woven Type-I collagen with some Type-III)

and elastin to create a compressible structure.

The major orientation of collagen fibres in the menisci is circumferential; radial and perforating are also present.

The circumferential fibres function in hoops to accept stress without gross deformation or extrusion of the joint.

Radial fibres stabilizes the meniscus, preventing circumferential splits as wells resisting excessive compressive loads.

The medial meniscus is semicircular and attached to the medial collateral ligament (medial collateral ligament) of the knee joint.

It only moves 2-5 mm within the joint and is hence more prone to tears than the lateral meniscus which is more circular in shape and moves 9-11mm.

The menisci of the knee are present developmentally at eight weeks as a collection of fibroblasts.

At birth, the menisci are vascularised through their substance; with ageing through early adulthood, there is eventual peripheralization of the vascularity to the outer third of meniscus.

Vascular supply is from the lateral and medial geniculate vessels ( inferior and superior).

The branches from the vessels give rise to perimeniscal capillary plexus within the Synovial and capsular tissue and supply the peripheral border of meniscus.

The depth of the vascular penetration is 10% to 30% of the width of the medial meniscus and 0% to 25% of width of lateral meniscus.

Acts as joint filler compensating for the gross incongruity between tibial and femoral articulating surfaces.

Prevent capsular and Synovial impingement during flexion-extension movements.

Joint lubrication help to distribute Synovial fluid through the joint and aiding the nutrition of articular cartilage.

Contribute to stability in all planes but are important rotatory stabilizers.

Shock absorption; the larger area provided by the meniscus reduces the average contact stress between the bones.

Traumatic lesions of the menisci are most commonly produced as the flexed knee moves toward an extended position.

The most common location of injury is the posterior horn of the meniscus, and longitudinal tears are the most common type of injury.

Menisci with peripheral cyst formation. Menisci that have been rendered less

mobile from previous injury or disease. Congenital anomalies-discoid lateral

meniscus. Areas of degeneration that develop as a

result of aging. Abnormal mechanics in the joint

incongruities or ligamentus disruptions.

Congenitally relaxed joints. Inadequate musculature especially

quadriceps. Certain sports are commonly associated

with meniscal injuries. Soccer players are particularly liable, especially when pivoting with the weight on one leg with the knee flexed. Other sports such as hockey, tennis, badminton, squash, and skiing are liable to meniscal injury.

Turning or twisting of the loaded joint may trap the menisci between the joint and tear the meniscus.

MEDIAL MENISCUS Internal rotation of femur over tibia

with knee in flexion forces the posterior segment of medial meniscus towards the centre of the joint.

The posterior horn may be trapped in this position by sudden extension of knee. This excessive force results in tear of the meniscus from its peripheral attachment and causes a longitudinal splitting of its substance.

Vigorous external rotation of femur while the knee is flexed will displace the posterior half of the lateral meniscus toward the centre of the joint.

During sudden extension of the knee, an anterioposterior distracting force tends to straighten the cartilage and imposes a strain on the medial concave rim, which tears transversely and obliquely.

Smillie’s classification Peripheral detachments(10%) Complete(23%) Segmental-either anterior or

posterior(2%) Horizontal tears-Posterior, middle or

anterior(48%) Cystic degeneration(12%)

Congenital anomalies Degenerative lesions

Based on the location of the tear in the three zones of vascularity.

a. Red-Red-fully within vascular area

b. Red-White-at the border of vascular

area c. White-White

within the avascular area

Based on the type of tear found at surgery

a. Longitudinal tear. b. Horizontal c. Oblique d. Radial tears e. Variations which include flap

tears, complex tears and degenerative tears.

Most commonly occur as a result of trauma to a reasonably normal meniscus.

The tear is vertically oriented and may extend completely through the thickness of the meniscus or may extend only partially or incompletely through it.

Medial side is 3 times more commonly involved than lateral.

If the tear is near the meniscocapsular attachment of the meniscus, it is referred to as peripheral tear.

Complete tear is associated with ACL injury.

Long tears that extend at least two third of the circumference of the meniscus produce an unstable fragment that displaces into the intercondylar notch, referred to as bucket handle tear.

Most common in older patients in the posterior horn of the medial meniscus or in the mid portion of lateral meniscus.

The horizontal cleavage divides the meniscus into superior and inferior leaves resembling a fish mouth.

Full thickness tears running obliquely from the inner edge of the meniscus out into the body.

If the base of the tear is posterior, it is referred to as posterior oblique tear; the base of an anterior oblique tear is in the anterior horn of the meniscus.

Common in lateral meniscus and middle third is commonly involved.

Three varieties are encountered,

1.Incomplete 2.Complete 3.Parrot beak In incomplete type,

tear extends all the way from the inner edge of meniscus out towards periphery.

In the complete type, tear extends all the way from the inner edge to meniscosynovial

rim. In parrot beak

variety, longitudinal or oblique tears are added to incomplete or complete radial tears.

It begins as horizontal cleavage tears in the degenerative tissue of an older patient.

It is superior or inferior flap depending on the location of the base of the flap.

It may contain elements of all the above types of tears.

More common in chronic meniscal lesions or in older degenerative menisci.

Most often seen in older patients. Present with marked irregularity and

complex tearing within the meniscus.

An accurate detailed history is essential and its importance is frequently greater than that of the clinical examination. Patient gives history of a twisting injury to the knee while the joint was flexed.

Locking: Locking means inability to extend the knee fully. This results as displaced segment interpose between the tibial and femoral condyle preventing full extension.

Sensation of giving away: The patient notices this on turning around suddenly, walking on uneven ground or on stepping on a mall stone and often associates it with a feeling of subluxtion or “the joint jumping out of place”.

Effusion: Indicates that something is irritating the synovium and has limited specific diagnostic value. Sudden onset after an injury denotes a hemarthrosis. Repeated displacement of torn portion of a meniscus can produce chronic synovitis with an effusion of a nonbloody nature.

Tenderness: Most important physical finding in localized tenderness along the medial or lateral joint line or over the periphery of meniscus. This is most often located posteromedially or posterolaterally

Atrophy of the quadriceps suggest recurring disability of the knee.

Clicks, snaps, or catches, either audible or detected by palpation can be valuable diagnostically. If the noises are localized to the joint line, the meniscus most likely contains a tear.

Often it is difficult to diagnose the cause of knee symptoms on history and clinical examination.

Such non specific symptom complex is termed as internal derangement of the knee.

Position: Supine Examiner stands on

the affected side; grasps the foot firmly with one hand and the knee with other hand

The joint is slowly extended slowly keeping the foot in externally rotated and abducted.

As the femur passes over the tear in the meniscus, patient complains of pain.

At the same time click will be felt by the hand at the knee.

On the similar exercise with the foot in internal rotation and knee adducted if elicits click and pain indicates tear in lateral meniscus.

Position: prone With the knee

flexed to 90 degree and the thigh fixed to the examination table clinician applies compression and lateral rotation to the leg from foot.

If the patient experiences pain it indicates M.M. tear.

If patient experiences pain on internal rotation of leg, a tear in lateral meniscus is suspected.

Consists of several repetitions of full squat with the feet and leg alternately rotated as the squat is performed.

Pain in the internally rotated position suggests injury to the lateral meniscus.

Pain in the external rotation suggests injury to the medial meniscus.

Position: Sitting Patient sits with the

leg bent over the table about 90 degree.

To assess the M.M. tear, the foot is externally rotated which produces some discomfort.

Position: Supine The examiner grasps the leg near the

ankle with one hand while flexing the knee to 30 degree with the other hand.

The patient is asked to relax and the knee is forcible and quickly extended in one moment or jerk.

As the patient passes from flexion to recurvatum the patient experiences a sharp pain on the side with the damaged meniscus which may radiate up and down the limb.

Radiological Examination: AP, Lateral and intercondylar notch

view with a tangential view of inferior surface of patella.

It is essential to exclude loose bodies, osteochondritis and other derangements of the knee.

Arthrography of the knee has proved to be a valuable supplement to analysis of knee disorders.

It is an invasive procedure. Air and an opaque contrast material such

as Iothalamate meglumine or diatrizoates sodium and megleomine are injected into the joint under sterile condition.

Multiple roentgenographic views are then made by rotating the joint and bringing all portions of medial and lateral menisci into profile.

Accuracy in diagnosis Medial menisci-95%

Lateral menisci-85%

It is contraindicated in pyoarthrosis, bleeding disorder and allergic to contrast material.

With the improvement in CT scan and MRI arthrography is rarely used.

Is the diagnostic procedure to detect the meniscal injuries.

It has an accuracy of 98% for medial meniscus injury.

It has an accuracy of 90% for lateral meniscus injury.

Ultrasound Scintigraphy CT MRI: Is currently of great value in

the diagnostic evaluation of meniscal tears.

The accuracy of meniscal tears exceeds 90%.They are graded as

Grade I Tear of the meniscus has increased signal in the meniscal substance.

Grade II Involves a more pronounced and frequently linear signal that does not break the surface of the meniscus.

Grade III Signal that traverses through the meniscal surface

Grade IV There is extension of tear through both tibial and femoral surfaces of the meniscus.

Grade I and Grade II changes appear normal on arthroscopic evaluation.

Injury to the alar pad of fat. Rupture of the medial ligament. Rupture of the cruciate ligament. Fracture of the tibial spine. Loose bodies. Osteo arthritis. Recurrent dislocation. Chondromalacia patella.

The damage to the menisci is often but one component of a complex injury to knee. The plan of treatment should be modified to accommodate for associated lesions.

Non Surgical management Surgical Management

Indication: 1. Incomplete meniscal tear or small

(5mm) stable peripheral tear with no pathological condition.

2. Tears associated with ligamentous instabilities can be treated non- surgically if patient defers ligament reconstruction or if reconstruction is contraindicated.

1. Chronic tears with superimposed acute injury.

2. In a locked knee with bucket handle tear of meniscus.

Initial treatment of a meniscal tear follows the basic RICE formula: rest, ice, compression and elevation, combined with nonsteroidal anti-inflammatory medications for pain.

1. An acute episode without locking but with an acute synovitis with effusion requires immediate abstinence from weight bearing, rest with knee flexion, application of ice packs and compression dressing.

2. Traction with 5 to 7 pounds of weight.3. Fluid should be aspirated.

5. A single intra-articular steroid injection should be permissible.

6. Squatting, flexion, external rotation and valgus stress to the knee to be avoided in the first week.

7. Groin to ankle cylindrical cast to be worn for 4 to 6 weeks.

8. Isometric exercise program during the time the leg is in cast.

9. At 4 to 6 weeks cast is removed and rehabilitative program is intensified.

10.If symptoms recur after a period of NST, surgical repair or removal of damaged meniscus may be necessary.

1. Meniscectomy By arthrotomy By arthroscopy2. Meniscal repair By arthrotomy By arthroscopy3. Meniscal transplantation With autografts, allograft, prosthetic

scaffolds.

Treatment of proven meniscal tear is usually either through arthrotomy or arthroscopy.

Arthroscopic techniques are preferred to arthrotomy unless associated injuries, such as ligament disruption or osteochondral fracture, require open techniques.

Types of meniscal excisions: Depending upon the amount of meniscal

tissue to be removed O Connor classified:

i) Partial meniscectomy: Only the loose, unstable fragments are excised; e.g. Displaceable inner fragment in bucket handle tear , the flap in flap tears or flap in oblique tears.

ii) In this stable and balanced peripheral rim is preserved.

ii) Subtotal meniscectomy: This requires excision of portion of peripheral rim of meniscus.

Most of the anterior horn and a portion of middle 3 rd of the meniscus are not resected.

iii) Total meniscectomy: Done when meniscus is detached from its peripheral menisco-synovial attachment and intrameniscal damage and tears are extensive.

1. Using single anteromedial incision: Begin the incision just medial to the

patella, continue it approximately 5 cm distally, parallel to the patella and the patellar tendon and end it at the level of upper tibia. Incise the fascia and capsule 0.5 cm medial to the edge of patella and patella tendon.

Using two incision: HENDERSON An additional posteromedial incision

is used. Permits easier and complete

detachment of posterior horn. Posterior incision is made 5 cm

parallel and slightly posterior to the tibial collateral ligament.

An anterolateral incision is made. Begin the incision at the level of mid

portion of the patella and extend it distally parallel to the patella and patellar tendon to the upper tibial surface.

If the posterior horn is not visible a second incision (HENDERSON) can be used.

A compression bandage is applied to the knee.

Knee is immobilized in extension with posterior plaster splint or with a knee immobilizer for 5-7 days.

Ice is applied over the knee and limb is elevated for 24-48 hours postoperatively.

Quadriceps exercises are started 2 nd day onwards, 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.

The sutures are removed 2 weeks and gentle resistive exercises are begun.

It is carried out as an diagnostic and an therapeutic procedure.

The objective of the treatment is to remove the torn mobile meniscal fragment and contour the peripheral rim leaving a balance , stable rim of meniscal tissue.

Longitudinal displaced complete intra meniscal tears (Bucket handle tear)

Technique: AM and AL portal’s is used to do partial meniscectomy.

It is used in the excision of large complete, intrameniscal tears of posterior horn.

Arthroscope, grasping instruments, cutting instruments are used through the three portals.

Arthroscope placed through the AL portal. Probe the posterior limits of displaced bucket handle through AM portal.

Through AM portal anterior horn attachment of the meniscus is released.

Grasping clamp is placed through the AM portal to grasp the anterior horn and it is removed.

Now probe is used through AM portal to check the stability of the remaining rim and look for any tears.

Motorized shaver are introduced through AM portal to smoothen the remaining rim.

30 degree viewing Arthroscope is inserted through an AL portal.

Probe is placed through the AM portal.

Objective is to perform partial meniscectomy.

Complete the contouring and balancing of the meniscal rim with the motorized shaver.

30 degree oblique viewing Arthroscope is used through AL portal.

Superior and inferior leaves of the tear is removed with the basket forceps.

Peripheral rim is trimmed and contoured.

Three portal technique is adopted, small posteriorly based oblique tears are usually removed by morcellation of flaps with basket forceps or motorized cutter, trimmer instruments.

Large posterior or oblique tears are removed enbloc.

Anterior oblique tears are removed by triangulation.

1. Post operative haemarthrosis.2. Chronic synovitis.3. Synovial fistulae.4. Painful neuromas of the branches of the

infrapatellar portion of saphanous nerve.5. Thrombophlebitis- suggested by

postoperative pain and swelling in the calf and distal extremity with low-grade fever.

6. Postoperative infection-Increasing effusion, pain and fever beginning 2 to 3 days after surgery indicate the onset of pyarthrosis.

7. Reflex sympathetic dystrophy.8. Retained meniscal fragment.9.Late changes: Degenerative changes

within the joint.

Fairbank described three changes i) Narrowing of joint space. ii) Flattening of the peripheral half of

the articular surface of condyle. iii) Development of anteroposterior

ridge that projected distally from the margin of femoral condyle.

Vertically oriented sutures are easy to do by open arthrotomy. It is more secure than more horizontally oriented suturing by arthroscopic techniques.

In repair of posterior horn peripheral tears by open arthrotomy technique, posteromedial or posterolateral capsular reconstruction can be done concurrently.

Since open incision is required to expose the capsule with arthroscopic techniques have no advantage over open technique.

Immobilization required is the same for both open and arthroscopic technique.

Certain tears are easier to suture by arthroscopic technique- posterolateral tears and tears central to menicosynovial junction.

Knee is placed in a hinged brace and immediate range of motion from 0 to 90 degree is permitted.

Touch down weight bearing is permitted immediately, and full weight bearing in 6 weeks after the brace and crutches are discarded.

No sports are allowed for 3 months.

If tear is large crutches are discarded at 8 weeks.

No sports are allowed for 6 months.

Tears that are definitely reparable include ,single vertical tear in the peripheral vascular portion of menisci, red-red zone, red-white zone within 3 mm of the junction.

Inside to outside Outside to inside All inside technique

Diagnostic arthroscopy Repair of M.M. tear place 30 degree

of Arthroscope through AL or central portal

Anterior limit of tear is seen with strong valgus strain with the knee flexed to 10-20 degree.

To approach anterior and middle third of medial meniscus tear straight cannula technique is used from lateral portal crossing under the arthroscope which is central or AM portal.

To approach posterior third of M.M. tear through AM portal with arthroscope located central or AL.

If the peripheral tear extends beyond PM corner of the knee an incision of 5-7 cm is made to preserve the popliteal vessels.

Long needles with swaged 2-0 ethaband are used.

Posterior tear of the lateral meniscus. 30 degree arthroscope view with an

AM portal and the probe in anterolateral portal.

Place the leg in figure of four position and advance 30 viewing arthroscope from AM portal to AL compartment.

Tear is sutured in 90 degree flexion.

The suture is introduced through a spinal needle that is inserted from outside to inside.

Safe technique for posterior horns. Large peripheral tears (bucket handle

tear) a combination of inside to outside and outside to inside methods are used.

Morgan described all inside technique.

Posterior horn peripheral meniscal tears within 3 mm of the menisco-synovial junction.

Advantages It allows the placement of vertical sutures thus securing the circumferentially oriented meniscal collagen fibres.

Smaller incision can be used. Disadvantages Need for special

instrumentation. Difficulty in tying the knot in a

confined space.

It acts as a chemo tactic and mitogenic stimulus for reparative cells and provide scaffolding for reparative process.

Arnocky and Warren reported the injection of exogenous fibrin clot obtained from the patients coagulated blood to improve meniscal healing.

Exogenous fibrin clot is injected with a blunt needle in the stem of the tear.

1-2 ml of clot was sufficient to fill an average defect.

When gaps are large facial sheath was used and fibrin clot is injected under the cover of the sheath.

Repairs of tears less than 2 months show higher healing rates.

Attempts at meniscal replacement with allograft menisci, auto graft fascial material and synthetic menisci scaffold are in various stages of study.

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