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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%)