POSTER ABSTRACTS - ISAKOS

Purpose: For ACL reconstruction using hamstring
grafts, a variety of fixation devices have been
successfully used. However, many of these devices
are expensive and can present artifacts in MRI as
well as complications in revision surgery.
Therefore, a novel Knot/pressfit technique that
eliminates the need for any fixation device has
been developed. The objective of this study was to
evaluate the biomechanical function of the
Knot/pressfit technique by comparing the
kinematics of the reconstructed knee with the
more commonly used EndoButton® CL fixation.
In addition, it is important wether stiffness and
strength of the Knot/pressfit fixation, under
uniaxial tension are equivalent to existing
methods.
Methods: Eight fresh-frozen human cadaver knees
(age: 52 ± 7 y.) were tested using a
robotic/universal force-moment sensor (UFS)
testing system. Two external loading conditions
were tested: (1) a 134N anterior tibial load (ATL)
at 0 , 15 , 30 , and 90 of knee flexion and (2) a
combined rotatory load of 10 N-m of valgus
torque and 5 N-m of internal tibial torque at 15
and 30 of knee flexion. The resulting five degrees
of freedom (DOF) knee kinematics of the intact,
ACL-deficient, EndoButton® CL and Knot/pressfit
reconstructed knee were determined, and their
differences were compared with a two-factor
repeated measures analysis of variance (p=0.05).
Subsequently, all Femur-Graft-Tibia Complexes
(FGTC) with the Knot/pressfit fixation were tested
in uniaxial tension until failure, and the stiffness
and strength of each specimen were obtained
from the resulting load-elongation curve.
Results: In response to the ATL, the anterior tibial
translation (ATT) for the Knot/pressfit
reconstruction was found to be not significantly
different for all four flexion angles tested to those
of the intact ACL as well as to those for the
Endobutton® CL reconstruction (p>0.05). In
response to a combined rotatory load, neither
reconstruction could effectively reduce the
coupled ATT to the level of the intact knee. The
coupled ATT of the Knot/pressfit fixation was
found to be 4.1 ± 2.8mm at 15 of knee flexion and
7.2 ± 2.7mm at 30 of knee flexion, which was not
significantely different from the Endobutton CL
fixation. Further, the stiffness of the FGTC was
found to be 37.8 ± 9.6 N/mm, while the load to
failure was 540 ± 97.7 N. These values are
comparable to those for the BPTB pressfit
technique and femoral fixation using Interference
screws.
Discussion: The Knot/pressfit technique for ACL
reconstruction was found to be able to restore the
knee kinematics. The ATT in response to the two
external loading conditions were similar to those
for the popular EndoButton CL technique. The
limitation was the lack of alternating order for
ACL reconstruction because the femoral tunnel of
the EndoButton technique could be used for the
Knot technique but not vice versa. Based on this
human cadaveric study, the Knot/pressfit fixation
is a reliable alternative for the femoral fixation of
hamstring grafts. In the future, in vivo studies of
the Knot/PressFit fixation including examination
of the tendon to bone healing are suggested.
KNEE - ARTHRITIS
E-poster #501
Gains of Viscco-supplementation Following
Arthroscopic Assisted Surgery in Limited
Gonarthrosis of the Femoro-Tibial Joint
Inderpreet Oberoi, INDIA, Presenter
Northern Railways Central Hospital, New Delhi,
INDIA
Introduction:
Osteoarthritis is a combination of both
mechanical and biochemical derangements.
Biochemically, there is reduction in concentration
and size of Hyaluronic acid in synovial fluid
resulting in its decreased viscosity and elasticity
and thus cartilage wear. The condral flaps and
particulate debris thus produced cause
mechanical derangement by repeatedly damaging
the joint and disease progression. It is thus
imperative to correct both biochemical and
mechanical deragements at an early stage so as to
ensure healthy pain free joint.
Material and Methods:
75 patients aged 48 - 72 years (Average 56.4 years)
with limited Gonarthrosis of femoro- tibial joint,
who had not responded to conservative treatment
were subjected to arthroscopic joint debridment.
The results of the treatment were compared with
those of 60 patients aged 51 - 71 years (Average
52.4 years) with similar problems treated with
arthroscopic joint debridment and 5 weekly intra
articular visco supplementation with 25 mg
sodium Hyaluronate (Hyruan) given thereon.In
selecting the patients, important considerations
were near normal mechanical axis (deviation