Ian Rice MD Meniscus Injuries - PowerPoint Presentation

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Ian Rice MD

Meniscus Injuries

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How far we haven’t come

“…It

is, however, a clinical fact that one of the semilunar cartilage, usually the internal one, does occasionally become loosened from its attachments; and, in consequence, this body is liable to be displaced either forwards or backwards, and so to interfere with the proper movements of the knee-

joint…”

1838 - 1907

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Among most common injuries seen in orthopedic practice

61 cases per 100,000 per

year

Arthroscopic partial

menisectomy one of the most common orthopedic proceduresEpidemiology

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Pathoanatomy

Overview

Crescent shaped and have triangular cross section

Fibers have circumferential orientation

Anterior and posterior root attachments prevent extrusionLateral covers 84% of the condylar surface, 12mm wide, 3-5mm thickMedial covers 64%, 10mm wide, 3-5mm thick

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Vascularity

Genicular

arteries

50% vascularized at birth

10-25% in adultsMakes healing very difficult3 vascular zonesRed-redRed-white

White-white

Pathoanatomy

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Collagen Organization

Circumferential fibers

Radial Fibers

Fine superficial layer around outside

Pathoanatomy

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Load Sharing

Increases contact area between femur and tibia

Decreases contact stress on articular cartilage

Increases congruity

Provides stabilityAids in lubricationMeniscal function

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In extension, 50% of the load is absorbed

At 90



flexion, 90% load-sharingBeyond 90

, forces predominate through posterior hornsBiomechanics

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Meniscal excursion with knee flexion

11.2 mm excursion of lateral meniscus

5.1 mm excursion of medial meniscus

Capsule

Deep MCLCoronary ligament

Meniscal Excursion

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Complete removal of meniscus results in 2-3X increase in contact stress

Removal of inner 1/3 = 10% reduction in contact area and 65% increase in stress

Increase loss of meniscal tissue = increase contact stress

Medial meniscal root tears have pressures similar to complete

meniscectomy

Biomechanics

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History

Twisting injury with change in direction in younger patients

Squatting or falling in older patients

Acute tear usually has insidious swellingJoint line location

Mechanical complaintsEvaluation

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Small effusion

Joint Line Tenderness

McMurray

Apley

ThessalyROM generally normalBucket handle blockTight due to effusion

Physical Exam

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McMurray

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McMurray

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Apley’s

Compression Test

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Thessaly Test

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Plain films to assess for bony injury and OA

MRI is the gold standard of diagnosis

Imaging

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Typically seen in younger patients

High association with ACL tears

90% of LVT in MM and 83% in LM are associated with ACL tears

Longitudinal Vertical Tears

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This is a LVT with central

margination

Most frequent type of displaced tear

Double PCL

Double Anterior HornAbsent Bow

Bucket Handle Tears

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Involves the free edge and propagates peripherally

Usually degenerative

Older patients

Horizontal Tears

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Also involve free edge, but path is perpendicular to long axis

Drastically affect ability to resist hoop stresses

Deeper the tear, the more drastic the biomechanical consequences

Radial Tears

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Radial Tears

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Radial Tear

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AKA vertical flap tear

Starts as a radial tear

Propagates as a longitudinal

Parrot Beak Tears

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Parrot Beak Tear

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Root Tears

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Non-surgical

Stable, longitudinal <10mm with <3-5mm displacement

Degenerative tears with concomitant OA

<3mm radial tears

Stable partial tears

Treatment

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Indications

Radial

Flap

Horizontal

ComplexWhite-white tears

Meniscectomy

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Goal is to debride tear and leave stable rim

Preservation is ideal

80% satisfactory function at 5 yrs

Lateral debridement = faster degeneration

Meniscectomy

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Predictors of Positive Result

< 40yo

Normal alignment

Minimal arthritis at initial scope

Single fragment tearMeniscectomy

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Relative Contraindications

Advanced OA

Complex tears

Poor tissue quality

ACL deficiency

Surgical Repair

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Open Repair

Rarely used

Numerous studies have proven reduced surgical morbidity with arthroscopic repair

Reserved for peripheral tears in the posterior horn

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Inside-out Repair

Suture passed on either side of tear with needle cannula

Suture is brought out of capsule

A small skin incision is made

Suture is tied down to capsulePosterior Horn Repairs

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Sutures passed through the meniscus from the outside

Eliminates need for larger incision

Generally suited for anterior repair

Studies have shown similar results with both techniques

Outside-In Repair

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All-inside repair devices were

developed to

reduce surgical time,

prevent complications resulting from external approaches, and allow

access to tears of the posterior hornFourth-generation repair devices allow placement of sutures in the meniscus

without the aid of an

external incision

or a suture

fixator

system

All Inside

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Self-adjusting, with

the anchor

located behind

the capsule and with a sliding knot that can be tensioned appropriately by

the surgeonMechanical studies show comparable strength to outside-in sutures

All Inside

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Outcomes

Success rates for all techniques reported 70-95%

Second-look scopes show lower success rates of 45-91%

Ligamentous laxity decreases success rate to 30-70%

90% success reported in conjunction with ACL repair

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Failure to heal

Stiffness

Articular surface damage

NV structure damage

Complications

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Transplantation

Indications:

Recurrent pain after partial or total debridement

symptomatic with ADLs

<50yoContraindications: MalalignmentLaxityInflammatory arthritisAdvanced OA

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Outcomes

Widely varying reports of success (Country differences)

Subjective improvement in

tibiofemoral

painNo clear long-term benefit in preventing OA has been establishedGrafts seem to do better when placed with a bone blockPreserving some peripheral rim helps to avoid extrusionVariety of meniscal scaffold options being investigated in animals

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