meniscal injury

Meniscal injury By

Dr.Mohammed Elbasheir Elhussein

Introduction

• The menisci are fibrocartilaginous structures that are semilunar in shape

and wedge-shaped in cross-section.

• Two menisci(medial and lateral) exist between the femoral and tibial

articulation.The femoral articulating meniscal surface is concave,whereas

the tibial articulating surface is convex.These surfaces conform to the

convex and concave opposing chondral surfaces, respectively.

• The conforming articulation provides perfect congruency between

the femoral condyle, meniscus,and tibial plateau, which establishes

the foundation for the biomechanical function of the menisci.

Introduction

Meniscal tears can be either

– Traumatic

or

– degenerative.

Introduction

• Degenerative tears have

been closely associated

with osteoarthritis.

Introduction

• Acute tears are often

related to trauma, most

frequently as a result of

a twisting motion.

• Most common in active

people aged 10–45.

Introduction

• Early diagnosis and

treatment of acute meniscal

tears can significantly

affect the short-term

meniscal viability and

subsequent long-term

articular chondral

protection.

Anatomy

Anatomy

Anatomy

Anatomy

• Blood supply

– medial inferior genicular artery

– lateral inferior genicular artery

AnatomyPopliteal artery

Anatomy

ILG artery

Anatomy

IMG artery

Anatomy

• Innervation

– peripheral two-thirds innervated by Type I and II nerve endings

– posterior horns have highest concentration of mechanoreceptors

Composition

Made of

1. fibroelastic cartilage

2. Collagen

3. Fibers

Stability

• medial meniscus

– posterior horn of medial

meniscus is the

main secondary

stabilizer to anterior

translation

• lateral meniscus

– is less stabilizing and

has 2X the excursion of

the medial meniscus

Function

• Force transmission

1. increasing

congruency

2. shock-absorption

3. transmits 50%

weight-bearing load

in extension, 85% in

flexion

Meniscal Pathology

• Epidemiology

– most common indication for knee surgery

– higher risk in ACL deficient knees

• Location

– medial tears

– lateral tears

• more common in acute ACL tears

Injury & Healing potential

• Tears in peripheral 25% red zone

– can heal via fibrocartilage scar formation

• Tears of central 75%

– have limited or no intrinsic healing ability

Classification

• Descriptive classification

– location • red zone (outer third, vascularized)

• red-white zone (middle third)

• white zone (inner third, avascular)

– size

– pattern 1. vertical/longitudinal

2. bucket handle

3. oblique/flap/parrot beak

4. radial

5. horizontal

6. complex

• The repairability of a meniscus depends on a number of factors these

include:

1. Age/strength

2. Activity level

3. Tear pattern

4. Chronicity of the tear

5. Associated injuries (anterior cruciate ligament injury)

6. Healing potential

Normal meniscus on MRI (left) and during arthroscopy (right)

Torn meniscus on MRI (left) and during arthroscopy (right)

Presentation

Symptoms

1. Pain, often along the joint line of the knee .

2. Swelling (“effusion” in the joint).

3. Inability to fully extend or flex the knee without discomfort .

4. Locking or catching of the knee.

5. Weakness of the leg.

Presentation

Signs • Joint line tenderness

• Effusion

• Positive McMurray's test

Imaging

• X-ray:

– Images (normally during weightbearing)

to rule out other conditions .

Imaging

• MRI

– Indications

• MRI is most sensitive diagnostic test, but also has a high false

positive rate

Treatment

Non-operative

Rest, NSAIDS, rehabilitation

• indications

– indicated as first line of treatment for degenerative tears

Treatment

Operative

– The definitive treatment of meniscal tears involves either repair or

excision of the pathologic tissue.

– Surgery.

Treatment

The indications for arthroscopy include

(1) symptoms of meniscal injury

(2) positive physical findings

(3) failure to respond to nonsurgical

treatment

(4) ruling out other causes of knee pain

Treatment

– Partial meniscectomy

• indications

– tears not amenable to repair (complex, degenerative, radial tear

patterns)

• outcomes

– >80% satisfactory function at minimum follow-up

– 50% radiographic changes (osteophytes, flattening, joint space

narrowing)

Treatment

– Meniscal repair

• indications

– best candidate for repair is a tear with the following

characteristics

» peripheral in the red zone (vascularized region)

» rim width correlates with the ability of a meniscal repair to

heal (lower rim width has better blood supply)

» vertical and longitudinal tear

» 1-4 cm in length

» acute repair combined with ACL reconstruction

Treatment

• outcomes

– 70-95% successful

– highest success when done with concomitant ACL

reconstruction

– poor results with untreated ACL-deficiency (30%)

Treatment

– Total meniscectomy

– of historical interest only

• outcomes

– 20% have significant arthritic lesions and 70% have

radiographic changes three years after surgery

– 100% have arthrosis at 20 years

– severity of degenerative changes is proportional to % of the

meniscus that was removed

Treatment

• Techniques of Partial Meniscectomy– approach

• standard arthroscopic approach

– technique • minimize resection

• do not use thermal (heat probes)

– postoperative • early active range of motion

• prolonged immobilization (10 weeks) is detrimental to healing in a dog model

Typical locations of arthroscopic surgery

incisions in a knee joint following surgery for a

tear in the meniscus

Treatment

• Meniscal repair

– approach

1-inside-out technique

– considered gold standard

– medial approach to capsule

– lateral approach to capsule

2-all-inside technique (suture devices with plastic or bioabsorbable anchors)

– most common

– many complications (device breakage, iatrogenic chondralinjury)

3-outside-in repair

– useful for anterior horn tears

– open repair

– uncommon except in trauma, knee dislocations

Treatment

Treatment

• Side effects of meniscectomy include:

1. The knee loses its ability to transmit and distribute load and absorb

mechanical shock.

2. Persistent and significant swelling and stiffness in the knee.

3. The knee may be not fully mobile, there may be the sensation of

knee locking or buckling in the knee.

4. The full knee may be in full motion after tear of meniscus

Treatment

• Meniscal Transplantation

– technique

• bone to bone healing with plugs at each horn or a bridge between horns

• peripheral vertical mattress sutures

• correct sizing of the allograft is essential (commonly based on radiographs, within 5-10% error tolerated)

Prevention

There are three major ways of

preventing a meniscus tear.

1. wearing the correct footwear.

2. Strengthening and stretching the

major leg muscles.

3. learning proper technique for the

movement.

Proper parallel squat form to improve knee stability

Complications

Saphenous neuropathy (7%)

Arthrofibrosis (6%)

Sterile effusion (2%)

Peroneal neuropathy (1%)

Superficial infection (1%)

Deep infection (1%)