The Wizard's potion
These are some of Don's interesting comments
from the Friday morning case conferences. Any errors in this section are
solely the poor recording of otherwise accurate comments, due to the pressure
of the quantity of interesting comments. This section is updated weekly.
To see the cases
This section has outgrown it's page and been subdivided.
Previous sections are linked below.
This page last updated on
05/06/2003 09:56:57 PM
Scripps conference 10/10/02: from Christine Lamoureux
- Limbus vertebrae: this may be due to a tunneling Schmorl’s node due to
injury or chronic stress before fusion occurred. Can be a part of
Schuerman’s disease. Be careful—similar tunneling may occur with mets
(prostate), and with the subperiosteal bone resorption associated with
- Arthography for SLAP lesions: normally, some contrast can be found
between the glenoid and the labrum superiorly. If the contrast is symmetric
and smooth in this space, it is more likely a normal finding. If it is
"tented" or not symmetric it is more likely pathologic.
- Bone graft donor sites in the posterior ilium especially in older
females can be associated with insufficiency fractures at the harvest site
and also at the pubic rami. This may be due to the fact that the sacroiliac
ligaments are removed and this can theoretically destabilize the pelvis.
Related note: the "Y"-shaped ligament of Bigelow (iliofemoral ligament) at
the anterior aspect of the hip joint is the strongest ligament in the body.
- Patterns of hip disease in males vs females: the protrusio acetabuli
measurements differ between the sexes. Also, there is a form of idiopathic
protrusio acetabuli in which patients can develop a medial pattern of
- Differential diagnosis of sacroiliac joint disease: includes Ankylosing
spondylitis, Reiters, Psoriatic arthritis, Infection. "Pseudosacroiliitis"
due to Paget’s disease can occur when there is Pagetic involvement of the SI
joints. In this case the SI joints are NOT ankylosed.
- Membranous lipodystrophy: characterized by lucent areas around the knee
or other joints that resemble lipomas; these can be associated with
pathologic fractures. This entity can be associated with a young patient
population affected by a leukoencephalopathy causing dementia-like symptoms.
- Case with sclerosis involving both knees stopping short of the
epiphyses—one possibility is Chester Erdheim/Erdheim Chester disease which a
histiocytic-type infiltration of bone. It is usually asymptomatic unless
there is extraosseous involvement (a nephritis similar to XGP).
- Ankylosing spondylitis and the cervical spine: differential is psoriatic
arthritis especially if there is involvement of the lower cervical spine and
the rest of the spine. AS is more likely if there is involvement of the
upper cervical spine as well. The classic pattern of AS involvement
beginning at the thoracolumbar junction and then extending superiorly and
inferiorly may not always be followed.
- Chondrocalcinosis: in 99 % of cases there is NO underlying disease or
familial character (ie, most cases are idiopathic). IF there is underlying
disease, these include primary hyperparathyroidism (look for resorption of
medial aspect of tibia), hemochromatosis, and more rarely, hypomagnesemia
(dense chondrocalcinosis), hypophosphatasia, Wilson’s disease (bone
fragmentation), gout (probably—affects fibro, not hyaline cartilage,
- Hypoplasia of the glenoid neck (denticulate glenoid): often bilateral,
asymptomatic OR associated with multidirectional instability, NOT usually
associated with dysplasia of the acetabuli.
Friday conference 10/11/02: from Christine Lamoureux
- Tendon pathology: tendinosis/tendonopathy is a preferred term over
tendonitis, as tendonitis infers that there is an inflammatory process going
on when histologically there is not.
- Superficial lesion at the tibial tuberosity which is lucent and
associated with a ring of high signal on T2WI: differential includes
cartilage tumors such as juxtacortical chondroma, epidermoid cyst, fungal (coccy,
crypto), giant cell reparative granuloma, and early Paget’s disease. Biopsy
- Lead in joints: "lead arthrogram"—lead can breakdown and outline the
capsule of a joint. It can be associated with synovitis and a destructive
arthritis. Lead toxicity can also occur when lead is found in joints, in the
spinal canal, or in the soft tissues when fluid cysts form around them.
- SLAP 9 lesion: the thicker the MGHL (middle glenohumeral ligament), the
more stable the glenohumeral joint is in general.
- Brodie’s abscess: number one location is the distal tibia, number one
organism is staph. The "channel" sign is a critical sign of Brodie’s
abscess. Some stop at the growth plate in the young, some penetrate it and
go into the joint, and some go horizontally. This is probably age-related.
Channel usually contains live organisms.
- Soft tissue mass anterior to the ankle joint: differential includes
tenosynovial chondromatosis and tenosynovial villonodular synovitis.
- Using osteopenia is not a reliable differentiator in musculoskeletal
Rheumatology Conference 10/11/02: from Christine Lamoureux
- Lipoma arborescens: associated with seronegative spondyloarthropathies.
Other synovial abnormalities (not necessarily related) include rice bodies
- A sesamoid bone may not have a true periosteum so can it truly have a
periostitis? Sesamoiditis is a described finding associated with the
- Paravertebral ossification is best seen on a frontal radiograph. To help
distinguish degenerative change vs spondylitis look at the SI joints.
- Deformities and erosions in the hand can be due to an overlap of
entities of a collagen-vascular nature.
- Osteonecrosis of the medial tibial plateau in patients with HIV:
etiology is attributed to antiretroviral therapy. There may be an
association with bone marrow lipodystrophy. Differential is neuropathic
and/or congenital insensitivity to pain.
- Bursitis can be septic or traumatic (such as dialysis elbow where the
patient rests the elbow on a table); other etiologies of bursitis include
RA, CPPD, and other crystal deposition diseases.
- "Shiny corners" and squaring of the vertebral body is more common in
ankylosing spondylitis than in psoriatic arthritis or Reiter’s.
HAD (hydroxyapatite deposition) in a joint capsule can be seen in chronic
renal disease and in collagen vascular diseases—if in one joint alone can be
Scripps conference 9/12/02; Friday am
conference 9/13/02 from Christine Lamoureux
- Hereditary Multiple Exostoses (HME) is
common around the knees. If there is another bone involved and the diagnosis
is in question, an AP view of the knees may help with the diagnosis.
- Osteochondritis Dissicans of the knee: this
is the second most common location for this process. Number one is talus.
Other affected sites include the capitellum at the elbow and the patella.
When it involves the knee, it is most commonly at the inner aspect of the
medial femoral condyle, at the non-weightbearing surface. When it involves
the lateral femoral condyle, it can be at the weight bearing surface or
along the anterior aspect of the lateral femoral condyle and can be obscured
by the overlying patella.
Presentation in the pediatric population is
usually managed by a "don’t touch"approach while those presenting in
adulthood often go to surgery. Stability of the osteochondral fragment can
be difficult in that granulation tissue can mimic actual joint fluid present
between the fragment and subjacent bone on MRI. MRI arthrography can be a
useful means to help make the distinction.
- A Salter Harris type 1 fracture of the base
of the nailbed is treated as an open fracture and has traditionally been
thought to be associated with a relatively high risk of infection. (Our
orthopaedic colleagues at conference ststed that they have the patient stop
activity with the involved digit and that it has not been their experience
that there is a high association with infection.)
- Entrapment neuropathy: in the shoulder, if a
ganglion is present in the suprascapular notch, the suprascapular nerve at
this level can be affected, with resultant effects on both supraspinatous
and infraspinatous muscles; if the ganglion is present in the spinoglenoid
notch, infraspinatous muscle alone may be affected. Clinically, entrapment
neuropathy can resemble a rotator cuff tear.
- SLAP lesions: there are at least 9 types.
The important thing is to be descriptive about the lesions in reports.
- Ankylosing spondylitis: facet disease in the
spine can precede syndesmophyte formation. The greater the restriction of
motion of the spine by facet ankylosis, the less formation of
syndesmophytes. When there is a fracture through a region of ankylosis of 2
vertebral bodies, increased motion and sclerosis at this level can mimic
infection. One must be careful diagnosing ankylosis of the posterior
elements of C2 and C3 as there posteror elements can overlap and produce
this effect. The "dagger" sign in ank spon is produced by interspinous
- Pagets disease is LEAST likely to affect the
clavicle, ribs and fibula.
- Calcium Pyrophosphate Deposition Disease
(CPPD): calcification can occur in the knee joint in both hyaline and
fibrocartilage and a distiction can be made radiographically.
- Case of a hand with findings consistent with
OA but with one of the PIP joints differing in that there were cystic
changes. Consistent with inflammatory OA, gout, CPPD, hydroxyapatite
- SCFE with secondary OA vs OA without a
history of SCFE: in both situations large medial osteophytes at the femoral
head/neck can be present. Look closely at the original zone of calcified
cartilage at the medial head—there is often a curvilinear line which
represents where the femoral head leaves off and an osteophyte begins—if you
can’t find it, SCFE probably occurred.
- Os perineum fractures: can be due to an
acute injury or be a stress-related injury. What is the "normal" position of
the os perineum? Usually at the level of the calcaneal/cuboid junction or
just distal to it at the facet of the cuboid. A peroneus longus rupture can
cause its dislocation. Fluid in Henry’s knot can be associated with these
- Unstable meniscal tear: the current
literature describes the definition as greater than 1 cm in length, a
complex lesion involving more than one plane, high signal intensity on fluid
sensitive sequences, and a displaced fragment. A large radial tear is also
considered unstable. Dr Resnick likes to look at the Fat Sat FSE coronals
for edema and radial tears.
- "Button" osteophytes: these are due to a
reduplication of the cartilage surface. They may mimic an intraarticular
- ACL or posterior root of the medial meniscus
can be associated with ganglion cysts of the tibial plateau. A general rule
is if there is an intraosseous cystic lesion, if it is at the weight-bearing
surface it is more likely degenerative in nature, and if it is at a non-weightbearing
surface and covered by cartilage it is more likely a ganglion cyst.
- Spondyloepeiphyseal dysplasia/dysgenesis:
according to Dr Pathria, the elbow is the first site to recognize this
abnormality. It can have an appearance similar to OCD of the capitellum.
- Quadriceps muscle tears: a good plane for
evaluation is saggital to evaluate the number of layers torn (usually 3).
There is debate as to which fibers may be important structurally (oblique?)
- Reiter’s in the hand: may be seen as bony
proliferation in the pisiform and radial styloid—this is a finding specific
for the seronegative spondyloarthropathies. There may or may not be
- Ankylosing spondylitis: hip disease is very
common, and is bilateral and symmetric in 60-70%
- The deep infrapatellar bursae: has an
H-shaped configuration and normally has a small amount of fluid within it.
- Calcific tendonitis: there can be associated
intraosseous penetration with associated marrow edema. This can be a mimicer
of chondroblastoma. A good book on this subject is by Cogman (?spelling)
published in the 1930’s.
October 4th 2002 from Christine Lamoureux
- Meniscocapsular separation: findings on MRI
may include high signal adjacent to the posterior aspect of the meniscus. This
is also more strongly suggested in the presence of adjacent tibial edema. If
there is a low signal plane between the region of abnormally increased signal
and the meniscus, a tear of the meniscus may be a more likely diagnosis.
- High signal in the symphysis pubis on
fluid-sensitive sequences in the athlete may be associated with avulsion
injury and is not necessarily consistent with classic osteitis pubis.
- Disk level calcification in the pediatric
population has been described in an article by Swischuck can be of multiple
etiologies (including infection). While these calcifications may resolve over
time, there can be long-term sequelae such as disk protrusions. These may
often occur at multiple levels in both the cervical and thoracic spine. They
have been associated with hydroxyapatite deposition but can also be associated
with oxalate deposition.
- On the topic of liposarcoma, 15-20 % may
contain fat on CT or MRI (according to Dr Pathria). On MRI fat can be seen
along septae within these lesions (especially in the
intermediately-differentiated lesions—myxoid liposarcomas).
- SLAP lesions: the "double oreo cookie sign":
this is composed of a buckethandle tear of the superior labrum and a sublabral
recess. In general, when evaluating SLAP tears it is best to be descriptive of
the pathology rather than focusing on the specific SLAP designation.
- The biceps tendon often can be seen to narrow
just before it attaches to the labrum and this is a normal finding.
- Tears of the subscapularis: one etiology is an
anterior glenohumeral joint dislocation. This tear involves the lower ½ to 2/3
of the subscapularis MUSCLE. Also, a helpful view in evaluating subscapularis
tears is the saggital view.
- Injury of the quadriceps tendon can be
associated with flipping over of the patella so that it is displaced anterior
to the patellar tendon (Dr Pathria).
September 6th 2002 from Christine Lamoureux
- Gamekeeper’s thumb involves disruption of the
ulnar collateral ligament which can displace superficial to the adductor
aponeurosis, called a Stener lesion. The injury is associated with fracture of
the phalanx about 90 % of the time. It is not easily identified by ultrasound.
- Rheumatoid arthritis/involvement of the distal
ulna: there are several involved compartments, including the radioulnar
compartment and the prestyloid recess.
- Definition of dorsal displacement of the ulna
on MRI: neutral, pronation, and supination views are obtained of both wrists.
There are several "rules" used to diagnose dorsal displacement: Dr Hughes
describes drawing a line along the posterior aspect of the ulnar styloid on a
lateral view. This line may be no more than 5mm posterior to the triquetrum
normally. Dr Resnick is familiar with this rule but questions its scientific
basis. Dr Chung describes a rule determining ulnar dorsal displacement which
includes determining whether the ulna is displaced posterior to Lister’s
- Definition of a rice body vs synovial
proliferation: rice bodies tend to be rounder and darker on MRI, are fibrous
and have pinched off as free fragments.
- Ankle arthography: it is important to
understand the structures normally filled in the ankle when no pathology is
present. For example, there normally isn’t filling around the peroneal
tendons. When there is, think of a calcaneofibular ligament tear. Fluid
collecting anterolaterally with respect to the ankle joint may indicate a tear
of the anterior talofibular (ATAF) ligament.
- The case of the missing patella: this syndrome
has many names, among them osteo-onychodysostosis, or Naill-Patella Syndrome.
Dr Resnick has observed an association of this entity with abnormal
compartmentalization of the femorotibial joint into medial and lateral
compartments on arthrography. The etiology is uncertain but may have to do
with abnormal development of plica.
- A fracture of the medial aspect of the lateral
tibial plateau may be seen with, but is not specific for, ACL tears.
- Atypical infectious process involving long
bones/jaw: Yaws. This is a treponemal infection seen mainly in the South
Pacific. Differential can include SAPHO.
- Cystic degenerative changes associated with an
ACL graft: usually seen in the tibial tunnel and has been seen with associated
ganglion cysts near the tunnel. Dr Chung points out differences in the
terminology commonly used: cystic degeneration within the graft proper vs
cystic degeneration of the actual tunnel.
- Meralgia Paresthetica neurocutaneous syndrome:
entrapment of the lateral femoral cutaneous nerve as it leaves the pelvis. May
be seen in obese patients, or associated with pelvic masses or tight
clothing/belts. A very painful condition.
- ELPS syndrome-thickening of the lateral
retinaculum with traction on the patella. Has been described as a possible
etiology for bipartite patella.