POSTER ABSTRACTS - ISAKOS

a role to play in the prevention of ACL injuries by
prophylactically targeting one of the variables
responsible for the increased ACL injury rates in
women.
E-poster #306
PLLA Ligament as a Ligament Augumentation
Device
Masao Ishimura, Ikoma, Nara, JAPAN, Presenter
Naohide Tomita, Kyoto, Kyoto, JAPAN
Takashi Habata, Kashihara, Nara, JAPAN
Yoshinori Takakura, Kashihara, Nara, JAPAN
Nara Mimuro Hospital, Ikoma, Nara, JAPAN
Since 1995, we have reconstructed the cruciate
ligament of knee joint using biodegradable Poly-
L-lactic acid (PLLA) .
The fibers of the PLLA ligament we used are
manufactured by melt-spinning out of high
molecular weight, exactly 233,000 daltons, poly-Llactide
polymer. The shape of the ligament is
plain braid and is the same as that of the Kennedy
Ligament Augmentation Device (Kennedy-LAD),
the material of which is polypropylene. Three
types of width, 5, 7 and 9 mm, were clinically
applied in this series. The initial tensile strength
of the 5 mm width ligament was 800 N, that of the
7 mm ligament was 1300 N, and that of the 9mm
was 1700 N.The degradation of PLLA occurs with
hydrolytic de-esterification into lactic acid and
then lactic acid is metabolized to pyruvate in
living organisms. The rate of degradation depends
on the molecular weight, size, and shape of the
implant.
In vitro hydrolytic degradation test in 37? C Saline
was performed for the polyglycolic acid (PGA)
braids and PLLA braids as a comparative study.
Time dependent decrease rate of tensile strength
in PLLA braid was lower than that in PGA. The
maximum tensile strength of PLLA braid
immersed for 24 weeks was 46 % and for 52 weeks
was 46% of the initial strength, respectively.
Animal studyies with 40 goats were performed. In
half of the 40 goats, each anterior cruciate
ligament was replaced with the composite graft of
an autogenous bone-patellar tendon-bone and a
5mm width PLLA ligament. The PLLA ligament
was used as the core of the tendinous portion of
the autogenous graft. Biomechanical and
histological examination showed excellent results.
Histological examination showed the complete
disappearance of the PLLA ligament from the
knee joint 2 years after operation.
Twenty-nine patients with the anterior and/or
posterior cruciate ligament insufficiency
consented to undergo operation with the PLLA
ligaments. Sixteen patients were male and 13
were female. Their age at operation was 26.4 years
on average ( 15 to 53 years).
Seven patients had combined anterior and
posterior cruciate ligament injury and underwent
combined anterior and posterior cruciate
ligaments reconstruction. In the ACL
reconstruction, a PLLA ligament of 5mm width
was used as the core of the bone-patellar tendonbone.
In the PCL reconstruction, a PLLA ligament
of 5mm width was used as the core of the 2 or 3
times folded semitendinosus and gracilis
tendons. Furthermore, a PLLA ligament of 9mm
width was passed between the folded tendons at
each end.
Eighteen patients had isolated ACL injury and
underwent reconstruction with the 2 or 3 times
folded semitendinosus and gracilis tendons
combined with a PLLA ligament of 7mm width at
each end.
Four patients had isolated PCL injury and
underwent reconstruction by the same way as the
PCL reconstruction in the combined ACL and PCL
insufficient cases.
Within the follow-up periods, ranged from 1 to 9
years (average 54.6 months), one patient with
isolated PCL reconstruction suffered temporary
hydrarthrosis of the operated knee. All of the
other patients had no local inflammatory sign and
had no abnormal data on the blood test.
Eighteen patients with isolated ACL
reconstruction were evaluated using JAPAN
Orthopaedic Association (JOA) scoring system and
International Knee Documentation Committee
(IKDC) evaluation form, KT-1000 arthrometer, and
repeat arthroscopy. The results of JOA score were
improved from 52.5 (36 to 81) to 86.6 (68 to 100)
on average. The FINAL EVALUATION of IKDC
Form was C in 5 cases and D in 13 cases
preoperatively and B in 3 cases, C in 13 cases and
D in 2 cases postoperatively. The results of
Manual Maximum Displacement test by KT1000
was 6.23mm on average (0.5 to 13.0mm)
preoperatively and 1.86mm (-2.0 to 8.5mm)
postoperatively. Repeat arthroscopy showed no
inflammatory sign in every cases and all
reconstructed ACLs were covered with synovial
tissue and the volume and tension of the ACLs
were excellent.