meniscal tissue degradation as the first sign of osteoarthritis. the process of mechanotransduction...
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Meniscal Tissue Degradation as Meniscal Tissue Degradation as the first sign of Osteoarthritis.the first sign of Osteoarthritis.THE PROCESS OF MECHANOTRANSDUCTION IN THE MENISCAL TISSUE.
Barbara ZielinskaMichigan University of Technology
Structure of the MeniscusStructure 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
HUMAN KNEE – top view Pho
tos
from
: Kne
e M
enis
cus-
Bas
ic a
nd C
lini
cal F
ound
atio
ns, 1
992,
Rav
en P
ress
NY
HUMAN KNEE – cross-section profile
MotivationMotivation
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.
Project definitionProject 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
Clinical Treatment of Meniscal Clinical Treatment of Meniscal TearsTears
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
Radial
Bucket-handle
Pho
tos
from
: Kne
e M
enis
cus-
Bas
ic a
nd C
lini
cal F
ound
atio
ns, 1
992,
Rav
en P
ress
NY
Aims of the studyAims of the study
Examine changes in contact parameters on superior surface of meniscus after medial meniscectomy.
Examine changes on lateral meniscus after medial meniscectomy.
Finite Element ModelFinite Element Model
FRONT VIEW
TOP VIEW
FEMUR
FEMUR CARTILAGE
TIBIA CARTILAGE
MEDIAL MENISCUS
LATERAL MENISCUS
TIBIA
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.
Simulations of Medial Partial Simulations of Medial Partial MeniscectomiesMeniscectomies
5 %
10 %
30 %
ANT-CENT CENT POST-CENT POST
ANT-CENT POST-CENT
60 %
ANT-CENT-POST
Intact CaseIntact CaseMEDIAL MENISCUS, SUPERIOR SIDEMEDIAL MENISCUS, SUPERIOR SIDE
MAX L3= 9 %MAX CP = 4.669 [MPa]
MEAN CP = 1.570 [MPa]
CONTACT PRESSURE (CP) AXIAL STRAIN (LE3)
POSTERIOR
ANTERIOR
Measurement of GAGsMeasurement of GAGs
Release of GAGs into the media after load from tissue explants is a sign of tissue matrix destruction.
GAG's Concentratiom vs. Compression
0
10
20
30
40
50
60
70
80
Load applied
Co
nce
ntr
atio
n 20% Load
.05 Mpa
.1MPa
Controls
GAG Concentration
0
10
20
30
40
50
60
70
80
% Compression (Load)
Co
nce
ntr
atio
n 5%
10%
15%
20%
Controls
Measurement of PGEMeasurement of PGE22
PGE2, an intracellular signaling molecule, is high in patients with OA and is necessary in the cell death process.
PGE2 TOP
-100
0
100
200
300
400
500
600
C
5%
10%
15%
20%
PGE2 BOTTOM
-150
-100
-50
0
50
100
150
200
250
300
350
400
C
5%
10%
15%
20%