POSTER ABSTRACTS - ISAKOS

using implantable force transducers. The
experiments were carried out with intact
ligaments and then after successively cutting the
PCL and ACL.
Results:
Tibial flexion osteotomy resulted in an anterior
shift of the tibiofemoral contact area and contact
pressure, leading to a decompression of the
posterior half of the plateau (p=0.002). The
increase of the slope resulted in a significant
anterior and superior translation of the proximal
tibia at all angles of knee flexion with a maximum
at 30 degrees (p=0.01). Posterior subluxation of
the tibial head after cutting the PCL was
completely neutralized with a flexion osteotomy
of 5 degrees (p=0.001). Strain in the anteromedial
bundle of the ACL was significantly increased with
a flexion osteotomy of 15 degrees and more
(p=0.01). The increase in tibial slope resulted in a
significant higher quadriceps strength which was
necessary for full knee extension (p=0.02).
Conclusion:
We conclude from these results that changes in
tibial slope have a strong influence on cartilage
pressure and kinematics of the knee.
Therapeutically a flexion osteotomy may be used
for decompression of the degenerated cartilage in
the posterior part of the plateau e.g. after
arthroscopic partial posterior meniscectomy. If a
valgus osteotomy is combined with a flexion
component of the proximal tibia, complex knee
pathologies consisting of posteromedial cartilage
damage, posterior and posterolateral instability
can be addressed in one procedure, which
facilitates a quicker rehabilitation of these
patients.
E-poster w/ Standard #762
An Experimental Study of the Effect of Vascular
versus Minimal Vascular Microenvironment in
Cartilage Healing
Asbjorn Aroen, Oslo, NORWAY, Presenter
Stig Heir, Oslo, NORWAY
Sverre Laken, OSLO, NORWAY
Finn Reinholt, Oslo, NORWAY
Lars Engebretsen, Oslo, NORWAY
University of Oslo, Oslo, NORWAY
Introduction. To investigate the repair potential in
a cartilage defect with or without access to bone
marrow elements at the basis of the defect sealed
by a rim-sutured periosteal flap.
Method. A partial thickness cartilage defect
(diameter 4 mm) was created in both patella of 35
rabbits at the age of 22 weeks. Two weeks later
access to the bone marrow was obtained by
drilling holes (diameter 0.6 mm) at the base of the
defect in one knee, treatment A, (vascular
microenvironment); whereas in the other knee the
base of the defect was left untreated, treatment B
(minimal vascular microenvironment). The defect
was covered with a rim-sutured periosteal flap in
both knees. In additional seven rabbits were
sham-operated at the same time points in one
knee, while the other knee was left untouched as
control. Animals were sacrificed 1, 2 and 36 weeks
after the second surgery and macroscopical
changes, synovial fluid contents, degree of filling,
thickness of cartilage rim and the subchondral
bone were evaluated.
Results. Histomorphometric measurements of
extend of filling (mainly fibrous tissue) of the
defect showed 50 % filling in treatment A
compared with 33 % in treatment B (p = 0.011). A
significant difference in height of the cartilage rim
between the experimental groups and shamcontrol
was measured, (p=0.005). Histological
signs of cartilage degeneration were observed at
the cartilage rim of the original defect and
included loss of chondrocytes and disruption of
the surface continuity in both experimental
groups. In additional treatment A resulted in a
significant increased thickness of the subchondral
bone in the defect in comparison to treatment B
at 2 weeks and at 36 weeks, (p= 0.021).
Interpretation. Both experimental treatments
showed incomplete repair consisting of fibrous
scar tissue and structural changes indicative of a
degenerative process in the defect and the
adjacent cartilage, but the degree of filling was
greater with a vascular than with minimal vascular
microenvironment
E-poster w/ Standard #763
The Operative Results of the Mosaicplasty for
Osteochondral Diseases in the Knee Joints who
were more than 40 years old
Yasuaki Nakagawa, Kyoto, JAPAN, Presenter
Takashi Suzuki, Kyoto, JAPAN
Yukihiro Okamoto, Kyoto University, Kyoto, JAPAN
Hiroshi Kuroki, Kyoto, JAPAN
Masahiko KOBAYASHI, Kyoto, Kyoto, JAPAN
Takashi Nakamura, Kyoto, JAPAN
Orthopaedic Surgery, Kyoto University, Kyoto,
JAPAN
[Purpose] It is said that the operative results of
the mosaicplasty for osteochondral diseases in