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PRESENTOR MODERATORDR. TAUSIF AHMAD DR. MOHD. FAIZAN

SURGICAL ANATOMY OF KNEE JOINT

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ANATOMY

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BASICS

Largest joint

Complicated joint

Commonly injured joint

Flexion and extension is possible but rotatory movement is also possible

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JOINTHINGE TYPE OF

SYNOVIAL JOINT Condyles of femur

articulates with condyles of tibia

PLANE GLIDING JOINT Patella articulates with

the lower end of femur

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THE DISTAL FEMORAL CONDYLES

Eccentrically curved.

Patellofemoral groove anteriorly.

Intercondylar notch posteriorly.

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THE PROXIMAL TIBIAL PLATEAU

Two flat surfaces

Separated by intercondylar eminence.

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THE PATELLA

Triangular sesamoid bone.Vertical ridge

Smaller medial and Larger lateral articular facet, or surface.

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LIGAMENTS

EXTRACAPSULAR Ligamentum patellae / patellar ligament Lateral / Fibular collateral ligament Medial / Tibial collateral ligament Oblique popliteal ligament

INTRACAPSULAR Cruciate Ligament

Anterior Posterior

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10Ligamentum Patellae / Patellar Ligament

•Continuation of quadriceps femoris tendon.

•Attached above to patella and below tibial tuberosity.

•Function• Directs force of quadriceps

femoris muscles to tibia during extension of knee.• Stabilizes patellofemoral joint.

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Lateral / Fibular collateral ligament

•Cord-like structure

•Attached to lateral femoral epicondyle superiorly

•Attached to lateralsurface of fibular head inferiorly.

•Function• Stabilizes lateral side of knee

joint, where it prevents medial flexion of joint.

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Medial / Tibial collateral ligament

•Broad and flat structure

•Attached to medial femoral epicondyle

•Inserted on medial margin and surface of tibia.

•Function•Stabilizes medial side of knee joint, where it prevents lateral flexion of joint.

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Oblique Popliteal Ligament

•Tendinous expansion from semimembranosus muscle.

•It strengthens the posterior aspect of the capsule

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ANTERIOR CRUCIATE LIGAMENT

Development Starts at 9th intrauterine weeks Completed at 18th week (Girgis et al. 1975 and Arnoczky et al 1983)

Two bundles Anteromedial: larger, tight in flexion Posterolateral: smaller, tight in extension (Xerogeanes et al 1995)

Prevents Anterior Displacement of Tibia Relative to Femur

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part of intercondylar area of tibia

At femur medial surface of lateral femoral condyle

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31 to 35 mm in length 31.3 mm2 in cross section.

Blood supply Middle Geniculate Artery. Inferior medial and lateral geniculate arteries.

Nerve supply: Posterior articular nerve, branch of the tibial nerve.

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POSTERIOR CRUCIATE LIGAMENT

•Attaches to the posterior aspect of the intercondylar area of tibia.

•At femur lateral surface of medial femoral condyle

•Restricts Posterior Displacement of Tibia

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Two major parts Large anterior portion: forms bulk of ligament Smaller posterior portion

Larger and stronger than anterior cruciate ligament.

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Meniscus

Meniscus Medial

Lateral

Roughly triangular in cross section

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MEDIAL MENISCUS

C-shaped structure

Larger in radius than lateral meniscus.

Posterior horn wider than the anterior.

Anterior horn attached to intercondylar eminence anterior to anterior cruciate ligament.

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Posterior horn anchored to intercondylar eminence in front posterior cruciate ligament

Peripheral border attached to medial capsule and through coronary ligament to upper border of tibia.

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LATERAL MENISCUS

Lateral meniscus - more circular

Anterior horn : Attached to tibia medially in front of intercondylar eminence.

Posterior horn: Inserts into the posterior aspect of the intercondylar eminence and in front of the posterior attachment of the medial meniscus.

Lateral meniscus is more mobile than medial meniscus.

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The posterior horn often receives anchorage also to the femur: Meniscofemoral ligaments Ligament of Wrisberg Ligament of Humphry

Support posterior cruciate ligament in minimizing displacement tibia.

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VASCULAR SUPPLY OF MENISCUS

Avascular

Vascular supply: lateral and medial geniculate vessels.

Depth of peripheral vascular penetration 10% to 30% of the width of medial meniscus. 10% to 25% of the width of the lateral meniscus.

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•3 zones:• Red-red• Red-white• White-white

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FUNCTIONS OF MENISCUS

Joint filler

Joint lubrication function Helping to distribute synovial fluid throughout the joint and aiding

the nutrition of the articular cartilage.

Reduces contact stress acting between the bones.

Shock- or energy-absorbing functions.

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Predominantly through descending and genicular branches from • Femoral• PoplitealOther arteries are: • Lateral circumflex femoral arteries in the thigh • Circumflex fibular artery • Recurrent branches from the anterior tibial artery in the leg.

These vessels form an anastomotic network around the joint

VASCULAR SUPPLY OF KNEE

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NERVE SUPPLY

The knee joint is innervated by branches from the obturator, femoral, tibial, and common fibular nerves.

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STABILIZERS OF KNEE JOINT

STATIC Joint capsule Collateral ligaments Medial patellofemoral ligament

DYNAMIC Quadriceps Gastrocnemius Pes anserinus Bicep femoris Tensor fascia lata Popliteus Semimembranosus

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STATIC STABILIZERS

Joint capsule Attached to the margins of

the articular surfaces Surrounds the sides and

posterior aspect of the joint. Absent anteriorly Posteriorly reinforced by

oblique popliteal ligament

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32Collateral ligament

Medial collateral ligament Principle stability to vulgus

stress

Lateral collateral ligament Principle stabilizer to varus

sress

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33Medial Patellofemoral

Ligament, Originates at the

Medial epicondyle MCL;

Inserts on superomedial aspect of patella; 

Resist lateral migration of patella

MPFL is effective between 0 and 30 deg flexion

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DYNAMIC STABILIZERS

Quadriceps 4 muscles form 3 layers

Rectus femoris : anterior Vastus intermedius: deep Vastus lateralis/ medialis:

middle Vastus medialis: two parts

vastus medialis longus vastus medialis obliquus

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35Gastrocnemius

Powerful calf muscle, Spans the posterior aspect of

knee Insert on posterior aspect of

medial and lateral femoral condyles

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36Pes anserinus

Conjoined insertion Sartorius Gracilis, and Semitendinosus.

Primary flexors of the knee Secondary internal rotational

influence on the tibiaHelp protect the knee against

rotary and valgus stress.

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37Biceps femoris

Strong flexor of the knee Produces simultaneous

external rotation of tibia. Provides rotatory stability

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38Iliotibial tract

Inserts Proximally:lateral epicondyle

of the femur Distally:lateral tibial tubercle

(Gerdy tubercle).Moves forward in extension

and backward in flexion but is tense in both positions.

Enhance lateral stability

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3 origins Lateral femoral condyle Posterior horn of the lateral meniscus From the fibula (popliteofibular

ligament)

Oblique Y-shaped ligament, the arcuate.

Prime medial rotator of the tibia Rotary stability to the femur on the

tibia Aids the posterior cruciate

ligament.

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Oblique popliteal ligament; Posterior capsule and posterior

horn of medial meniscus; Anterior or medial tendon of

semimembranosus; Direct head of

semimembranosus; Distal portion of

semimembranosus tendon Flexor of knee and internal rotator

of tibia. Posterior stabilizer of knee.

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Q-ANGLE

Described by BrattströmAngle formed by line of pull of quadriceps mechanism and that of

patellar tendon.Represented by intersection of line drawn from anterior superior iliac

spine to center of patella with second line drawn from center of tibial tuberosity to center of patella.

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Normal value 8 to 10 degree in male 10 to 20 degree in female

Increased in Genu valgum Increased femoral anteversion External tibial torsion Laterally positioned tibial tuberosity Tight lateral retinaculum

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Locking mechanism

3 components Change in shape and

size of femoral surfaces that articulate with the tibia Joint surfaces become

larger and more stable in extension

Medial rotation of the femur on the tibia during extension.

Body's center of gravity Passes anterior to the

knee joint

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Reduces the amount of muscle work needed to maintain the standing position

Popliteus muscle unlocks knee by initiating lateral rotation of femur on tibia

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References

Gray’s anatomy anatomical basis of clinical practice 40th edition

Gray’s anatomy for students 2nd editionSnell’s clinical anatomy by region 9th editionNetter’s atlas of human aanatomy 5th editionCampbell’s operative orthopedics 12th editionSurgical exposures in orthopedics the anatomical

approach by S. Hoppenfeld 4th editionGrant’s atlas of human anatomy

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