POSTER ABSTRACTS - ISAKOS

E-poster #710
Three Cases of Meniscal Cysts Arising in the
Popliteal Space
Kazushige Nomura, JAPAN, Presenter
Gunma Sports Medicine Research Center,
Maebashi, JAPAN
OBJECTIVE: The purpose of this study is to
describe the MR imaging features of an unusual
type of meniscal cyst arising from tears of the
posterior horn of the medial meniscus and its
treatments.
MATERIALS AND METHODS:Retrospective review
of MR examination of the knee was performed on
3 patients (one man, two women; mean age, 50
years) in whom evidence of a meniscal tear and a
cyst-like structure in the popliteal space was seen.
An oval mass with low signal intensity on T1-
weighted MR images and increased signal
intensity on T2*-weighted MR images in the
popliteal space, simulating a PCL ganglion cyst,
was seen in all 3 patients. A tear of the posterior
segment of the medial meniscus was also seen in
all 3 patients.
Arthroscopy in 3 patients and open cystectomy in
2 patients confirmed the meniscal tear and the
meniscal cyst.
CONCLUSIONS:In our case, only partial
meniscectomy was performed, and to date there
have been no recurrences.
The treatment strategy for meniscal cysts and PCL
ganglion cysts differ.
Accurate preoperative diagnosis of a pericruciate
meniscal cyst is important.
E-poster #711
The Meniscal Ossicle Revisited: Etiology and a
Novel Treatment
David R Diduch, Charlottesville, VA, USA,
Presenter
Ole Raustol, Charlottesville, VA USA
Anikar Chhabra, Charlottesville, VA USA
Kornelis A. Poelstra, Charlottesville, VA USA
University of Virginia, Charlottesville, VA, USA
The etiology, significance, and treatment options
of the meniscal ossicle are unclear. Although only
41 cases are described in the literature, several
theories exist on its origin, including a
phylogenetic theory and a post-traumatic theory.
MRI and arthroscopic findings have suggested a
radial tear or meniscal root avulsion, and a
calcified posterior horn of the medial meniscus.
Removing this ossicle may further destabilize the
posterior root attachment of the medial meniscus
and create laxity in the circumferential collagen
bundles. Since the clinical significance is
uncertain, there is no consensus on treatment
options. We present our evolving experience with
a case series of meniscal ossicles, including a
series of arthroscopic cases and one total knee
arthroplasty case that led us to believe that the
ossicle results from an avulsion of the posterior
root of the medial meniscus. Lastly, in an acute
presentation, we present a novel technique for
repair of a meniscal ossicle in two cases.
A series of arthroscopic cases presented with
MRI’s and clinical findings ranging from possible
loose bodies to radial tears of the posterior
medial meniscus. Intraoperatively, each case
revealed a rounded, calcified posterior horn of the
medial meniscus detached from its root insertion
similar to a radial tear. Using accessory portals
posteromedially and through the notch,
visualization of an apparent avulsion donor site
from the tibia at the normal root attachment was
evident. An open arthroplasty case with removal
of the tibial plateau and menisci en bloc
confirmed the root avulsion theory. The detached
ossicle and tibial donor site were easily visualized
with apparent secondary laxity in the meniscus
circumferential tension.
With this working theory, we acutely encountered
a 15-year old male soccer player following a
twisting, contact injury. His clinical exam, MRI,
and arthroscopy were consistent with a posterior
root avulsion of his medial meniscus.
Visualization of his meniscal ossicle was aided by
passing the arthroscope under the PCL into the
notch. The avulsed posterior root was folded back
on itself, exposing the osseous undersurface, and
the two opposing superior surfaces of the
meniscus were beginning to scar together.
Following preparing the donor bed, a
posteromedial portal was created to perform the
repair. The avulsion could be reduced to the
donor site, resulting in reduction of the entire
meniscus into its original position and tension on
the tibial plateau. The root of the medial
meniscus and the avulsed ossicle were pierced
twice with a Beath needle which was drilled into
the anterolateral edge of the donor site and out
through the anterolateral tibial cortex to create an
outside-inside-outside, mattress suture repair.
The sutures were pulled thought the tibia,
tensioned, and tied over a 10mm bone bridge on