Meniscal Tissue Degradation as the first sign of Osteoarthritis'

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Meniscal Tissue Degradation as the first sign of
Osteoarthritis.

• THE PROCESS OF MECHANOTRANSDUCTION IN THE
  MENISCAL TISSUE.

Barbara Zielinska Michigan University of
Technology
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Structure of the Meniscus

• C-shape (wedge-shape in cross-section profile)
  disks of fibro cartilage
• Interposed between the condyles of the femur and
  tibia

• Strong attachments to bone
• Inner 2/3 poor vacularization

Photos from Knee Meniscus- Basic and Clinical
Foundations, 1992, Raven Press NY
HUMAN KNEE cross-section profile
HUMAN KNEE top view
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Motivation

• Studies show that the meniscus is involved in the
  early stages of OA development.
• A better understanding of the loading environment
  and biochemical response of meniscal tissue may
  help us understand the etiology of OA.

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Project definition

• FE model of medial partial meniscectomy
• MEASUREMENT OF THE CHANGES IN THE CONTACT
  PARAMETERS ON THE MENISCUS AFTER DIFFERENT
  PARTIAL MENISCECTOMIES
• Biochemical tests on the post incubated media
• MEASURMENTS OF THE AMOUNT OF VARIOUS
  MOLECULES RELEASED INTO THE MEDIA AFTER DIFFERENT
  LOAD CONDITIONS
• Real time RT-PCR
• MEASURMENT OF THE GENE EXPRESSION IN THE
  MENISCAL TISSUE AFTER DIFFERENT LOAD CONDITIONS

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Clinical Treatment of Meniscal Tears

• Meniscal repair
• Does not heal in avascular zone (Arnoczky, S.P.
  1992 King, D. 1936)
• Allograft
• Poor fixation technique
• Difficulties with finding a donor of correct size
• (Paletta, G.A.,et al., 1997 Peters, G.A. et
  al.,2003 Felixs, N.A. Paulos, L.E., 2003)
• Partial meniscectomy
• Changes in contact area and stress distribution
  contribute to osteoarthritis (OA)
• (Baratz, M.E. et. al., 1986 Fukubayashi, T.
  Kurosawa, H., 1980 Cole, B.J., 2004 Rangger,
  C., et al., 1995 Cox, J.S., et a., 1975
  Wyland, D.J., et a., 2002 Fahmy, N.R.J et al.,
  1983)

DIFFERENT TYPE OF TEARS
Horizontal
Photos from Knee Meniscus- Basic and Clinical
Foundations, 1992, Raven Press NY
Radial
Bucket-handle
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Aims of the study

• Examine changes in contact parameters on superior
  surface of meniscus after medial meniscectomy.
• Examine changes on lateral meniscus after medial
  meniscectomy.

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Finite Element Model
FEMUR CARTILAGE
FEMUR
MEDIAL MENISCUS
TIBIA CARTILAGE
FRONT VIEW
TIBIA
LATERAL MENISCUS
Donahue, T.L., et al., A finite element model of
the human knee joint for the study of
tibio-femoral contact. J Biomech Eng, 2002.
124(3) p. 273-80.
TOP VIEW
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Simulations of Medial Partial Meniscectomies
ANT-CENT
CENT
POST-CENT
POST
5
10
ANT-CENT
POST-CENT
ANT-CENT-POST
30
60
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Intact CaseMEDIAL MENISCUS, SUPERIOR SIDE
POSTERIOR
ANTERIOR
CONTACT PRESSURE (CP)
AXIAL STRAIN (LE3)
MAX L3 9
MAX CP 4.669 MPa MEAN CP 1.570 MPa
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Measurement of GAGs

• Release of GAGs into the media after load from
  tissue explants is a sign of tissue matrix
  destruction.

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Measurement of PGE2

• PGE2, an intracellular signaling molecule, is
  high in patients with OA and is necessary in the
  cell death process.

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Real time RT-PCR

• Measurement of Collagen, COX-2 and MMPs gene
  expression.
• COX-2 is responsible for elevation of the PGE2
  level
• MMPs- enzymes which are capable of collectively
  degrading all kinds of extracellular matrix
  proteins