POSTER ABSTRACTS - ISAKOS

increased until 48W and the MM decreased in
120W (P < 0.01). No significant feature of DT was
observed. IT of LC, MC and LTP, which was the
highest in 3W, significantly decreased in 8W (P <
0.01) and the value was maintained until 120W.
Contrary to them, IT of MTP was the lowest in 3W.
It slightly and insignificantly increased in 8W, then
it was maintained until 48W and significantly
increased in 120W (P < 0.01). Actual thickness of
cartilage observed was agreed with the data of IT.
Discussion: Ultrasonic evaluation revealed
maturation-dependent change of cartilage,
especially in MM and IT. In any sites, stiffness of
cartilage, which was represented as MM, was low
in 3W. Although most of data indicated that
cartilage became stiff in 24W or 48W, there were
some differences after 48W. In LC, MC and MTP,
MM was significantly or insignificantly decreased
in 48W or 120W, i.e. the cartilage became soft, but
in LTP, MM was maintained the value after 24W,
i.e. the cartilage maintained stiff. Data of surface
irregularity, which was represented as DT,
revealed that the surface of cartilage was smooth
regardless of maturation. Results of IT indicated
that thin cartilage of MTP in 3W became thick in
120W, which is late stage of maturation, and that
thick cartilage of LC, MC and LTP became thin in
8W, which is early stage of maturation.
Conclusion: Although the number of animals was
limited, maturation-dependent change in stiffness
and thickness was revealed. The differences in the
maturation-dependent change at the 4 sites may
suggest which site is easy to be affected after the
late stage (120W) of maturation.
E-poster #720
Arthroscopic Analysis of the Lateral Meniscal
Variants
Hee-Soo Kyung, Daegu, KOREA, Presenter
Yong-Gu Kim, MD, Daegu, KOREA
Joo-Chul Ihn, MD, Daegu, KOREA
Seong-Ki Park, MD, Daegu, KOREA
Kyungpook National University Hospital, Daegu,
KOREA
OBJECTIVES: The purpose of this study was
arthroscopic analysis of the lateral meniscal
variants.
METHODS: 164 cases of 158 patients were
analyzed in recent 10 years. This was 13.6% of the
arthroscopic surgery and 28.2% of the arthroscopic
meniscectomy in the same period. Male was 85,
female 79 cases. The mean age was 27.9 years(3-
62). Left side was 69, right side 81 cases. and 14
cases(8.5%) were bilateral. We classified the types
as complete, incomplete, Wrisberg, and ringshaped
type. The tear pattern was simple
transverse tear, complex transverse tear,
longitudinal tear, complex tear, radial tear and
central-wear tear. We also compared MRI and
arthroscopic findings between ring-shaped
meniscus and central-wear type of discoid
meniscus.
RESULTS: There were complete type 131 cases
(79.9%), incomplete type 25 cases(15.2%), ringshaped
meniscus 4 cases(2.4%), and Wrisberg
type 4 cases(2.4%). About tear pattern, transverse
tear was most common 54 cases(32.9%) with
simple transverse tear 33 cases(20.1%) and
complex transverse tear 21 cases(12.8%). And
there were longitudinal 37 cases(22.6%), centralwear
27 cases(16.4%), complex tear 14 cases(8.5%)
and radial tear 12 cases(7.3%). Discoid meniscus
without evidence of any tear were 20 cases
(12.2%). We performed subtotal meniscectomy 77
cases, partial 43 cases, total 24 cases and no
resection 20 cases. Twelve patients(13 knees,
7.9%) had osteochondritis dissecans of lateral
femoral condyle: nine patients(10 knees) of them
had central tear, two patients(2 knees) of them
had simple horizontal tear, and one patient (1
knee) had ring-shaped meniscus. Among 31 knees
with central tear or ring-shaped meniscus, we
reviewed 25 MR images, which were interpreted to
all bucket-handle type tear of normal meniscus by
trauma.
CONCLUSIONS: Careful history about trauma and
careful reading of MRI finding were very important
for diagnosis of the discoid meniscus. It was
essential to distinguish ring-shaped meniscus or
central tear of discoid meniscus from the buckethandle
tear of normal meniscus.
E-poster #721
Radial Displacement of the Torn Medial
Meniscus on MRI
Yoshiki Shiozaki, Sakai, Osaka, JAPAN, Presenter
Shuji Horibe, Sakai, Osaka, JAPAN
Takashi Natsu-ume, Sakai, Osaka, JAPAN
Keisuke Kita, Suita, Osaka, JAPAN
Konsei Shino, Habikino, Osaka, JAPAN
Osaka Rosai Hospital, Sakai, Osaka, JAPAN
INTRODUCTION: Radial displacement of the
medial meniscus is considered loss of the
meniscal function resulting in progression of
varus osteoarthritis. However, either its etiology
or correlation to osteoarthritis is unknown. The