POSTER ABSTRACTS - ISAKOS

The passive range of flexion was the same in all
cases, although small differences were found in
the initial attitude of the joint in full extension.
The elongation and orientation of the
reconstructed ACL bundles were similar both in
the horizontal and vertical case and differed in
their position and orientation from the central
fibre of the natural ACL, especially in extension.
The anterior bundles of the reconstructed ACL
resulted isometric during PROM, like the normal
ACL central fibre, while the posterior bundle
decreased its length in flexion by almost 20%.
Also the orientation of the anterior bundles of the
reconstructed ligament with respect to the tibial
plateau was similar to the normal one and
decreased in flexion. The orientation of the
posterior bundle of the reconstructed ACL with
respect to the tibial plateau varied much more
during PROM.
The orientation of both anterior and posterior
bundles of the reconstructed ACL with respect to
the femoral notch were quite similar, and
increased less than normal ACL during PROM.
It is interesting to remark that the attitude of the
knee at 90? was slightly different for normal and
reconstructed knees and therefore the elongation
during IE and drawer test showed a different
trend.
This is confirmed by the results of the kinematic
stress tests. In fact AP and IE laxities varied
according to the ACL state, as the mean among all
repeated tests in the same conditions.
Discussion and Conclusions:
The experimental setup was successful in
providing a comparison among normal knee, ACLdeficient
knee and reconstructed knee from the
kinematic point of view, avoiding the problem of
individual variability and lack of data on 3D
kinematics.
In our experiment the ACL elongation and general
orientation of the ligament was restored by both
techniques [2,3]. However only the vertical tunnel
was able to restore the natural AP and IE stability
of the knee. It performed better than the
horizontal one, which appeared unable to fully
control AP laxity and constrained IE rotation more
than the normal ACL.
Therefore a first analysis of the experimental data
showed that the femoral tunnel orientation had a
significant effect on the final knee behaviour,
probably because it produced a different global
length of the used tendon or, although small,
different positions of the antero-medial or
postero-medial bundle of ACL reconstructions. In
fact all the other features of the reconstructions
were the same in the two examined technique (i.e.
the graft, the tibial tunnel, the position of the
anterior and posterior bundle of the reconstructed
ACL).
It can be noticed that this result appears
surprisingly different from the classic single
bundle technique, were the control of AP laxities
increases when the orientation of the femoral part
becomes more horizontal [4]. This result may be
due to the physical behaviour of the tendon
wrapping around the femoral condyle with
different length and therefore forces in the two
double-bundle techniques and absent in the
single-bundle one.
We plan to perform a more extensive experimental
study of this issue in the near future.
References
[1] Martelli S., New Method for simultaneous
anatomical and functional studies of articular
joints and its application to the human knee,
Comp Methods & Programs in Biomed, 70: 223-
240, 2003 .
[2] Zaffagnini S., Martelli S., Acquaroli F.,
Computer investigation of ACL orientation durino
passive range of motion, Computers in Biology
and Med, 34:2, 2004 (to appear)
[3] Sapeva A.A. et al., Testing for Isometry during
reconstruction of the anterior cruciate ligament,
JBJS 72-A[2]:259-267, 1990
[4] Edwards T. B et al., In vitro comparison of
elongation of the ACL and the single- and dualtunnel
ACL reconstructions, Orthopedics, 22
[6]:577-84 , 1990
E-poster #332
Clinical Outcome and Second-look Findings of
Amateur Athlete with Bi-socket ACL
Reconstruction using Multiple Hamstring
Tendons
Atsushi Inoue, Sapporo, JAPAN, Presenter
Kazuhiko Nakano, Sapporo, JAPAN
Toshiaki Yamamura, Sapporo, JAPAN
Nishioka Daiichi Hospital, Sapporo, JAPAN
Purpose
The purpose of this study is to verify whether
sport activity level of amateur athlete after ACL
reconstruction influences the clinical outcome at
post-operative one year and the graft in secondlook
arthroscopy.
Materials and Methods