A 27-year-old male visited our hospital because of severe pain in
the popliteal area that occurred when the knee was flexed actively
beyond 100o during squatting or flexed passively beyond 120o in
the crossed leg position. He had struck the lateral side of his left
knee against the fence alongside a ski slope while snowboarding 8
weeks earlier, and the symptoms aggravated despite conservative
management. He had no history of trauma prior to that event.
On physical examination, the anterior drawer test was grade 1
(4 mm) and the Lachman test result was a firm end point. The
pivot shift, posterior drawer and valgus stress tests were negative.
The patient complained of tenderness around the medial femoral
Plain radiographs of the knee were normal. However, magnetic
resonance imaging (MRI) of the left knee showed a bone marrow
contusion on the lateral tibial plateau, sprains of the anterior
cruciate ligament (ACL) and medial collateral ligament (MCL).
In addition, MRI demonstrated a rounded and well-demarcated
soft mass anterior to the PCL, and the ligament was slightly
deformed due to the mass. The cystic lesion was seen originating
from the deep recess between the posterior root of the MM and
the PCL that bulged into the posteromedial joint space with a
signal change in the posterior root of MM and the PCL adjacent
Symptomatic Posterior Cruciate Ganglion Cyst Causing
Impingement between Posterior Root of the Medial
Meniscus and Anterior to the Posterior Cruciate
Yong Bum Joo, MD and Young Mo Kim, MD, PhD
Department of Orthopedic Surgery, Chungnam National University Hospital, Chungnam National University College of Medicine, Daejeon, Korea
This is an Open Access article distributed under the terms of the Creative Commons
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Copyright © 2012. THE KOREAN KNEE SOCIETY
Knee Surg Relat Res 2012;24(1):52-55
pISSN 2234-0726 · eISSN 2234-2451
Knee Surgery & Related Research
There are several reports of symptomatic ganglion cysts near the posterior cruciate ligament (PCL), but no reports of a symptomatic ganglion
originating from the anterior aspect of the PCL in the deep recess between the posterior root of the medial meniscus and the PCL, bulging into
the posteromedial joint space. In this report, we present the clinical features of a patient with a symptomatic ganglion cyst treated successfully by
Key words: Knee, Posterior cruciate ligament, Posterior root of medial meniscus, Ganglion cyst, Arthroscopic excision.
Received July 3, 2011; Revised (1st) August 2, 2011;
(2nd) September 7, 2011; Accepted September 15, 2011.
Correspondence to: Young Mo Kim, MD, PhD.
Department of Orthopaedic Surgery, Chungnam National University
College of Medicine, 282 Munhwa-ro, Jung-gu, Daejeon 301-721, Korea.
Tel: +82-42-220-7352, Fax: +82-42-252-7098
There are many reports of ganglion cysts observed in various
joints. Cystic masses of the knee are relatively common1), but
intra-articular ganglion cysts related to the posterior cruciate
ligament (PCL) of the knee are rare2,3). In particular, a cyst in the
anterior aspect of the PCL is rarer than in the posterior aspect4).
We report a case of a symptomatic ganglion cyst that originated
from the anterior aspect of the PCL in the deep recess between
the posterior root of the medial meniscus (MM) and the PCL.
Knee Surg Relat Res, Vol. 24, No. 1, Mar. 2012 53
to the cyst (Fig. 1).
Arthroscopy revealed a cystic lesion, about 7 mm in diameter,
originating from the anterior aspect of the PCL between the
posterior root of the (MM) and the PCL (Fig. 2A). During knee
flexion, the cystic lesion enlarged as it was compressed between
the posterior root of the MM and the PCL, and it impinged on
the articular cartilage of the posterior MFC, the posterior root of
the MM, and the PCL (Fig. 2B). In addition, a dimple was found
on the articular cartilage of the posterior MFC adjacent to the
cystic lesion (Fig. 2C). When the cyst was punctured, a jelly-like
viscous fluid was extruded, and some degenerative soft tissue
attached to the PCL was identified. We removed the cystic lesion
completely along with some fibers from the PCL adjacent to the
cystic lesion where the signal change was seen on MRI (Fig. 2D)
and the specimen was sent to the pathology department. We
did not find any significant instability related to the ACL, PCL,
or MCL, and no other intra-articular pathology. The histologic
examination of the cystic tissue showed proliferation of synovial
cells with mild chronic inflammation and cystic space lined
by fibrous connective tissue with focal myxoid degeneration,
confirming the diagnosis of ganglion.
The symptoms improved immediately after the operation. At
12 months postoperatively, the patient was able to perform all
activities of daily living, including squatting and sitting in the
crossed leg position, and had full range of motion (ROM). No
instability of the knee joint was detected. The Visual Analogue
Scale had decreased from 9 preoperatively to 1.
Although ganglion cysts in various joints have been reported
frequently, intra-articular ganglion cysts arising from the PCL
are uncommon2,3). Brown and Dandy5) reported that only 6 of
35 ganglion cysts of the cruciate ligaments arose from the PCL
in 6,500 arthroscopic examinations of knees over a period of
13 years. In addition, the cyst in the anterior aspect of the PCL
is rarer than that in the posterior aspect4). In particular, we did
not find any reports of a symptomatic ganglion originating
from the anterior aspect of the PCL in the deep recess between
the posterior root of the MM and the PCL that bulges into the
Fig. 1. (A) Axial fat-suppressed T2-weight-
ed MR image and (B) sagittal turbo spin
echo T2-weighted MR image showing an
intervening lobulated cystic lesion (asterisk)
located in the deep recess between the
posterior root of the medial meniscus (black
arrow) and the posterior cruciate ligament
(PCL) (white arrows). (C) Consecutive
coronal fat-suppressed T2-weighted MR
images and (D) proton density MR image
showing a lobulated cystic lesion with
internal septation (small arrow) abutting
the posterior medial femoral condyle. The
cystic lesion abutted the anteromedial
aspect of the PCL, which showed some
fraying and increased signal intensity (white
54 Joo and Kim. Symptomatic Posterior Cruciate Ganglion Cyst Causing Impingement
posteromedial joint space.
Ganglion cysts arising from the PCL are increasingly recognized
due to the sensitivity of MRI for visualizing intra-articular
abnormalities. The finding of an ovoid fluid filled cystic lesion,
which is frequently multilocular, in the intercondylar notch MRI
has been described as characteristic3). It has been suggested that
these lesions should be treated by arthroscopic excision5). In our
case, MRI showed the fluid filled and lobulated cystic lesion.
The clinical manifestations of a cyst are largely dependent on
the pathologic process involved, along with its location, size,
mass effect, and relationship to surrounding structures1). One
of the typical clinical manifestations seen with a ganglion cyst
of the cruciate ligament is a diminished ROM2,6). Tachibana
et al.6) described the symptoms present with an intra-articular
ganglion arising from the posterior joint capsule of the knee
joint. They suggested that the development of knee pain during
flexion and the inability to fully flex the knee could be explained
by compression of the mass between the PCL and the posterior
joint capsule. In our case, we believe that the pain arose from
both compression of the ganglion cyst in the deep recess between
the posterior root of the MM and the PCL during knee flexion,
and the impingement of the ganglion cyst on the posterior MFC
articular cartilage, the posterior root of the MM, and the PCL
The histogenesis and pathogenesis of ganglia are unclear, and
many theories have been proposed2). Trauma has been advocated
as playing a role in the pathogenesis of ganglion formation2). A
blow to the lateral aspect of the leg mostly causes injuries to the
medial side of the knee including the MCL, and may deliver
a twisting force that can damage the ACL and possibly even
the PCL7). We postulated that the ganglion cyst that arose in
our patient may be of traumatic origin based on the similarity
between the MRI findings and the mechanism of injury.
Treatment options vary according to the symptoms and the
suspected diagnosis in any given case1). The complete resection
of the mass is often technically demanding or impossible8). We
removed the ganglion cyst and some fibers of the PCL adjacent
to the cystic lesion where a signal change was seen on MRI.
Subsequently, the patient’s symptoms disappeared.
1. Beall DP, Ly JQ, Wolff JD, Sweet CF, Kirby AB, Murphy
MP, Webb H, Fish JR. Cystic masses of the knee: magnetic
Fig. 2. Arthroscopic finding of the post-
eromedial compartment of the knee joint.
(A) The ganglion cyst originated from the
anterior aspect of the posterior cruciate
ligament (PCL) in the deep recess between
the posterior root of medial meniscus (MM)
and the PCL. (B) During knee flexion, the
cystic lesion was enlarged and impinged on
the articular cartilage of posterior medial
femoral condyle (MFC), the posterior root
of the MM, and the PCL. (C) A dimple
was found on the articular cartilage of
the posterior portion of the MFC (arrow)
where it was in contact with the cystic
lesion at high flexion. (D) The cystic lesion
and some fibers of the PCL adjacent to the
cystic lesion were removed.
Knee Surg Relat Res, Vol. 24, No. 1, Mar. 2012 55
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and significance of cysts found at MR imaging behind the
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Bui-Mansfield LT, Youngberg RA. Intraarticular ganglia
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5. Brown MF, Dandy DJ. Intra-articular ganglia in the knee.
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