06 Chouteau Bio Mechanics Od the MPFL Copy

8/3/2019 06 Chouteau Bio Mechanics Od the MPFL Copy

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MPFL: Biom ec hanic s

Dr Julien Chouteau PHU MD PHD , Pr Bernard Moyen

Department of Orthopaedics, Trauma and Sport Medicine, Lyon-Sud Hospital, Pierre-Bénite,

France

Efort Instructional Course, Lyon March 2011



MPFL

Medial

PatelloFemoral Ligament



Superficial Layer:

Medial Retinaculum

LAYERS

ON THE MEDIAL ASPECT

OF THE KNEE



Second (intermediate) layer:(same as MCL)

Medial

PatelloFemoral ligament

(MPFL)

LAYERS


OF THE KNEE



Deepest Layer:

Medial PatelloMeniscal

ligament (MPML)

LAYERS


OF THE KNEE

MPMLLenght 39.4 ± 3.2mm

Width 9.6 ± 1.2mm



LAYERS


OF THE KNEE

Deepest Layer :

MedialPatelloTibial ligament

(MPTL)

MPTLLenght 54.6 ± 8.4mm

Width 21.8 ± 4.4mm

MPFL & MPTL Found in 47%



MPFL ANATOMY

Philippot, Chouteau and al 2009, 23 cadaveric knees

MPFL Always Observed

Lenght : 57.7 ± 5.8mm

Width

• at the femoral insertion: 12.2 ± 2.6mm

• at the patellar insertion: 24.4 ± 4.8mm



Jonction between vastus medialis

obliquus (VMO) and MPFL

Always founded

Genuine reflection zone with intertwined

MPFL and VMO fibers Length 25.7 ± 6mm

MPFL ANATOMY



• 40% of the knee

•

Strong relationshipbetween the MPFL and

the superficial bundle of

the MCL• Ligamentous Arch

Relationship

MPFL / MCL



Relationship

MPFL / MCL

Ligamentous arch( Smirk et al, Colan et al)



Femoral Insertion

HAUT

MEDIAL Tubercle of the

great adductor

Femoral MPFL

Insertion

Medial

Epicondyle

11.2 mm

10.7 mm



Philippot, Chouteau and al (Kssta 2009)

Orthonormal frame centered

on the femoral insertion of the MPFL

F point

• Behind and Proximal to the Medial Epicondyle Point

10.7 ± 3.3mm

• In Front and Distal to the AT point 11.2+5.9mm

Femoral Insertion



Patellar Insertion

Upper half on the medial

edge of the patella

Also inserted on the patellar

end of the quadriceps tendon

Quadriceps tendon and VMO

( Colan et al, Smirk et al, Tuxoe et al).



BIOMECHANICS

Strength of the MPFL

• 10 cadaveric specimens (mean age 70 y)

• Mean failure load 208N



BIOMECHANICSFunction of the MPFL

MPFL load during Flexion

Elias (Am J Sport Med 2006)

Maximum 20N at 30° flexion

Near 0N at 90° flexion



Control of the patellar lateral

displacement (%)

Conlan (JBJS Am 1993) 53%

Desio (Am J Sport Med 1998) 60% (41-80)

Hautamaa (CORR 1998) 50%

BIOMECHANICS

Function of the MPFL



From Amis, The Knee 2003

“Graph of patellar lateral displacing force at 10

mm displacement,for the intact knee with 175

N quadriceps tension, and after transection of

the MPFL.The drop between the two curves

shows that the contribution of the MPFL wasgreatest in the extended knee.”

*significant difference.

BIOMECHANICS




• Specific protocol to evaluate the

function of the MPFL

BIOMECHANICS




Philippot, Chouteau and al

KSSTA 2010

All three bone segments

marked so that relative

movements of the three segments

could be monitored with respect

to each other and in the six

degrees of freedom

BIOMECHANICS




Kinematics on the Healthy knee

and after MPFL section

BIOMECHANICS




Healthy Knee

• Patellar tilt Almost zero through

the first 45° of knee flexion

From 45°, the patella underwent external tiltingwhich became accentuated towards 90° flexion,

reaching a maximum of -3.7 ± 8.9mm with respect to

the reference position

BIOMECHANICS





Healthy Knee

• Patellar Shift

• The patella progressively

shifted externally

to reach, at 90° flexion, a maximum shift of 3.18 ±

9.67 mm with respect to the reference position




•Healthy Knee

• Patellar Rotation

Through the first 30° of knee flexion, the patella

showed medial rotation, reaching a maximum

amplitude of 0.8 ± 4.6 at 15° of flexion

then a switch to lateral rotation, reaching a maximum

of 1.45 ± 6.5 at 90° flexion




Patellar Shift

After section of fibers VMO/MPFL

• No statistically significant modification

After section of the MPFL• Statistically significant Increase in lateral patellar shift

(maximal in extension and decreasing with flexion)




Patellar Shift After section of the MPFL

72% increase at full extension, 52% at 90° flexion




Lateral Patellar Tilt After section of the MPFL

Statistically significant increase

Maximal in extension




Lateral Patellar Tilt Control After section of

the MPFL

MPFL 76% at full extension and 28% at 90° flexion



Patellar Rotation control Lateral rotation after MPFL section from

extension to 35° flexion




Patellar Rotation control after

MPFL section

62% at full extension, 0% from 35°




CONCLUSION

MPFL Consistently found in all dissections in the

second thickness of the knee’s medial plane

Main Medial Stabilizer of the Patella

from Full Extension to 30° Flexion



THANK YOUDr Julien Chouteau PHU MD PHD , Pr Bernard Moyen

Department of Orthopaedics, Trauma and Sport Medicine, Lyon-Sud Hospital, Pierre-Bénite,

France

Julien chouteau@chu-lyon fr

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06 Chouteau Bio Mechanics Od the MPFL Copy