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 click here
This section has outgrown it's page and been subdivided. Previous sections are linked below.
April 26th 2002 Ortho
1. OCD in children is usually benign, with only1/100 becoming loose. Can use retrograde drilling to encourage revascularisation. Retrograde uses a gig to locate lesion and a gattling gun arrangement of drills.
2. A discussion of the various techniques for diagnosing AVN of the proximal scaphoid. Far from clear cut. Proximal pole Fx more prone to AVN than waist Fx.
3. Patella dislocation
Fixed - Down's, Infancy
Obligatory - Dislocates with cycle, Dysplasia, less severe
4. Post shoulder dislocation is 2% of all.
Anterior dislocation is associated with anterior labroligamentous periosteal sleeve avulsion, and posterior capsule avulsion.
5. When diagnosing a Buford complex, no tissue should be seen passing posteriorly to the glenoid on the sagittal images, unlike a sublabral foramen.
6. Lipoma next to bone may cause erosion/periosteal reaction, often spiculated. Liposarcoma has thicker septa.
7. ACL tears. Anteromedial rotatory instability does not relate to the movement of the tibia at the time of injury, but rather that the ACL is torn and the medial aspect is injured. If the MCL bows out anteriorly the medial patella femoral ligament is likely torn
April 26th 2002 Rheum
1. Mid body scaphoid erosions on lateral aspect can lead to Fx.
2. Can occasionally have radiolunate ankylosis in RhA
3. Ank spond affects costo transverse joints.
4. Primary synovial osteochondromatosis of the hip can cause femoral neck Fx.
April 19th 2002 Ortho
1.Indirect shoulder MRI arthro. Exercise for 15 mins post injection, pre MRI.
2. ACJ seperation
Grade 1. Stretched AC lig. Force down on acromium. No op.
Grade 2. Torn AC lig, stretched CC lig. No op.
Grade 3. Torn AC and CC ligs. Rx controversial.
Grade 4. AP force. Clavicle posterior. Torn AC and CC ligs. Rx-Op recon.
Grade 5. Bad 3 with wide seperation, torn deltotrapezoid fascia. Rx-Op recon
Grade 6. Inferior seperation of clavicle.
3. ACJ meniscus always degerates with age.
4. Navicular stress fatigue Fxs. Sagittal plane, dorsal surface.
5. Bronchogenic mets can have a shell of ossification.
6. Venous malformation; slow flow, fluid level in sinusoids, can have calcifications
Vascular malformations; 4 types
High flow, Haemangioma in child - resolves, don't treat.
AVM - don't resolve. i.e. Klippel Trenauney Webber, infact grow.
Low flow, Venous malformations - slow flow, phleboliths, fluid/fluid levels
Klippel-Trenaunay syndrome; VV's, ST and bony hypertrophy, cutaneous hemangioma.
Parke-Weber = KTW + AV fistula.
Kasabach-Merritt syndrome; Papillary hemangioma, purpura and bleeding diatheses.
April 12th 2002 Ortho
1. Scalloping of the anterior distal femur is caused by CPPD arthropathy.
2. A persistent median artery may be the cause for a divided median nerve.
3. Signs of chronic active osteomyelitis include: Immature periostitis, abscess, change, sequestrum. The sequestrum indicates active infection since the bodies immune system cannot penetrate the dead bone.
4. Fat necrosis is fat signal surrounded by oedema. This may be caused by pressure necrosis, or by the panniculitides such as Weber Christian, erythema nodusum or pancreatitis.
March 29th 2002 Ortho
1. SAPHO, synovitis, acne, pustulosis, hyperostosis, osteitis. Related to sternocostclavicular hyperostosis SCCH and Chronic recurrent multifocal osteomyelitis CRMO, previously known as plasma cell osteomyelitis. Bony proliferation associated with pustulosis, usually on the hands. Described by Dr. Jurek from Denmark. Pustules do not have to be present. Age differences: chest wall and sternum are common. Young; pagetoid clavicle with lower extremity metaphyseal lesions. Old; chest wall and spine. Like SCCH, with masses on medial clavicle. Middle aged; mixed. Consider if osteitis pubis boney sclerosis only involves one side of the joint, or discogenic sclerosis (Modic 4) only on one side of the disc. In the femur it produces diffuse sclerosis. The cause is likely a reaction to the skin lesions, rather than due to the bacteria themselves. SCCH tends to have more costal cartilage calcification. Condensans osteitis clavicle involves the medial end of the clavicle, and there are no skin lesions.
2.Peroneus longus has two tendon sheaths: The common one shared with peroneus brevis, and a more distal one as it passes beneath the cuboid.
3. For a lesion of the tibial tuberosity consider fungal infection such as cocci or crypto. Alos remember that Pagets can start from such an apophysis.
4. A Brodies abscess can have a penumbra sign on MRI due to the thick rim having low signal on T1.
5. There is possibly a relationship between transient bone marrow oedema and osteonecrosis.
6. The erosions of PVNS and synovial osteochondromatosis at the hip cause an apple core pattern to the neck and involve the acetabular fossae.
7. The calcification of hyperparathyroidism is CPPD, not just simple metastatic calcification. For the same no of patients with both primary and secondary hyperparathyroidism, CPPD and brown tumours are more common in primary.
8. Cookie bite mets are usually from lung adeno.
9. Gout often involves the TMTJs. The signal is heterogenous on both T2 and Gd.
March 22nd 2002 Ortho
1. The lateral cord of the plantar aponeurosis attaches to the lateral aspect of the medial calcaneal process, not the lateral calcaneal process. The abductor digiti minimi attaches to the lateral process. Middle cord fans out to all 5 toes. The lateral cord has medial and lateral bands. The lateral band passes to the base of the 5th MT on its plantar aspect, the medial band passes to the 3rd and 4th MTPJs. Also attaching to the base of the 5th MT is the peroneus brevis on the dorsal aspect with the peroneus tertius.
2. The anterior tib fib ligament is multipenate.
3. Mucoid degeneration of the ACL causes increased girth and signal on all sequences. This may predispose to rupture.
4. Intraosseus lipoma: Miligram 1988 Radiology.
1. Non necrotic fat with trabecular resorption. Pure radiolucent areas
2. Necrotic fat, calcification.
3. (Involuted) cysts, reactive woven bone/ central calcification, necrotic fat, peripheral rim of fat, thick peripheral rim of sclerosis, can be expansile.
LFMFT may be end of spectrum with increased malignant transformation.
5. A desmoplastic fibroma is a trabeculated lytic lesion.
6. Diabetics are prone to muscle infarction. 1/3 bilateral, resolves spontaneously. Can also occur in sickle cell disease, Lupus, poly and dermatomyositis, hyperkalaemia. Usually thighs and calves. Ddx pyomyositis (which have muscle oedema and abscesses). Muscle enzymes may be normal. May be febrile. Occurs in poorly controlled IDDM.
7. With fibrous or cartilainous lunotriquetral coalition there is often a widened joint and there may also be widening of the scapholunate joint.
8. Nurse maids elbow is a pull on the pronated arm of a child such that the radial head slips from under the annular ligament without a tear of the annular ligament. Essence of a radial dislocation is a tear of the annular ligament.
9. There are three talocalcaneal ligaments:
The lon thin cervical
The short fat interosseus
The lateral interosseus
10. Patella: Excessive lateral pressure syndrome ELPS
1. Lateral patellofemoral joint space narrowing.
2. Lateral OA
3. Medial facet osteoporosis
4. Hypoplasia of lateral trochlea
5. Patella tilt, not subluxation
6. Lateral retinacular thinning
7. Lateralisation of trabecular to the lateral facet. They normally run at right angles to the patella equator, but now angle more anterolateral.
Also a condition called excessive lateral tension syndrome ELTS.
March 22nd 2002 Rheumatology
1. If there is decreased joint space of the SIJ but no erosions, consider DISH
2. With ankylosing spondylitis the proliferative new bone at the superolateral aspect of the femoral head is ill defined.
3. With ankylosing spondylitis of the cervical spine there can be a ghost of the facet joint, due to ossification of the capsule prior to interosseus ossification of the articular cartilage.
4. Bone proliferation of the radial and ulna styloids, consider sero negative.
5. Highe signal in rotator interval, consider adhesive capsulitis.
6. The phalangeal heads can be enlarged in gout.
7. Look for a sternal buckle fracture in patients with a dowager hump from osteoporosis.
8. With midcarpal (pericapitate) and CMC joint arthritis consider juvenile idiopathic arthritis or adult onset Stills disease.
9. Osteoporosis of the spine has a pencil thin sharp cortex, but osteomalacia has ill defined margins.
March 21st 2002 Scripps
1. Erosions and sclerosis of the ischial tuberosity are a feature of Ankylosing spondylitis. This becomes purely sclerotic when the disease is quiescent. AS causes axial joint space narrowing of the hip with a femoral cuff of osteophytes. Psoriatic and Reiter's rarely affect the hip. 16 years of age divides AS from JAS.
2. Ollier's is not just enchondromas, and can have juxta cortical lesions. Ollier's and Maffucci's are not hereditary. Vertical columns of cartilage can be seen extending from the physis. It is unclear if this is tumour or growth aberation.
3. Sacral involvement is common in Paget's. Lucent with coarsening.
4. Dentate glenoid or hypoplasia of the glenoid neck is nearly always bilateral. Can be associated with a smaller humeral head and a dipping acromium. The posteroinferior glenoid is replaced by fibrous tissue. can be thought of as DDH of the shoulder.
5. Talocalcaneal coalition or peroneal spasitc flat foot, is probably commoner than calcaneonavicular coalition, but the books may report otherwise due to CN being easier to see on plain films and TC better seen on CT.
Facets and joints:
Posterior subtalar joint = Posterior facet
Anterior subtalar joint = Middle facet + anterior facet
Middle facet is the sustentaculum articulation
Anterior facet is small and on the lateral aspect of the horizontal portion of the calcaneonavicular or spring ligament. It articulates with the head of the talus.
The anterior joint communicates with the talonavicular joint.
6. Meniscal cysts may be intra or peri. Intra may be an expanded horizontal tear.
7. Multiple subcutaneous nodules in the foot could be due to fibromatosis. More common on medial side. Can look aggressive, but no malignant potential. Have increased frequency of desmoids and other fibrous tumours. Ddx gout.
8. Distal biceps tendon rupture may have an associated irregular radial tuberosity due to preexisting tendinopathy/enthesopathy.
March 15th 2002
1. Occasionally the coracoid tip can be positioned more laterally or posteriorly than usual. This may cause subcoracoid impingement upon the subscapularis and lesser tuberosity. Often oedema in lesser tuberosity. Distance between coracoid and humeral head less than 8-11mm, but htis will be affected by humeral rotation and any glenohumeral joint laxity. Subscapularis impingement is well seen with dynamic ultrasound. Other possible measurements include a line extended anterior parallel to glenoid fossa and measure distance that coracoid extends lateral to this. Coracoid raoation may be related to previous trauma.
2. With PVNS the hemosiderin may extend down vascular channels to produce the bony erosions/cysts.
3. Osteochondral defects can be due to acute or chronic trauma, OCD or SONK. Probably all traumatic, repetitive minor or single major. Osteonecrosis likely secondary. Age, sex and location are best distinguishing features. Fluid suggests instability. Drill the stable, remove the unstable.
4. Plantar fasciitis often has associated oedema in the calcaneous. Usually central cord. Medial cord blends with the central. Lateral cord probably from lateral aspect of calcaneus, possibly lateral process. Can have secondary rupture. Rx not surgical for first year of symptoms. If discontinuous at the level of the calcaneocuboid joint, could be due to previous surgical release.
5. Ewings of the pelvis can have lots of sclerosis and a large soft tissue mass.
6. Surgery for clasp knife phenomenon has shown fibrosis around the thecal sac at the S1 level where the L5 spinous process projects on hyperextenson.
7. If see infection of the upper cervical spine consider TB
March 8th 2002
1. Be aware that a recent steroid injection at the lateral epicondyle can mimic lateral epicondylitis on MRI. Called tennis elbow but thought to be due to the back stroke. ? if double handed reduces risk. Radial nerve and posterior interosseus nerve problems can mimic LE. Possibly increased signal also seen in anconeus.
2. A ganglion occurs when fluid leaks into a pseudo capsule from a minor ligament or tendon injury and becomes inspisated. On the dorsum of the hand this often seems to pass between the two band sof the radiolunotriquetral ligament.
3. Rotator cuff tears of the hip will often have atrophy of gluteus minimus or medius and can simulate trochanteric bursitis.
4. Hydroxyappetite within the reflected head of rectus femoris can be associated with cortical erosions. Small os acetabuli which may not look ossified are difficult to differentiate.
5. An ALPSA is a soft tissue Bankart with an intact periosteum. Often this becomes scarred and retracted medially. Since a Bankart may also become scarred down, chronically they may be difficult to seperate. This most important finding in shoulder instability for the surgeon is to know if the failure is on the glenoid or humeral side.
6. Neurogenic tumours (Schwanoma, Neurofibroma and Malignant peripheral nerve sheath tumour) are usually: fusiform, have a nerve entering and exiting, split the fat, have low density on CT and a target on MRI. A schwanoma sits eccentrically on the nerve, a NF has the nerve fibres divided around the tumour. If they become malignant, they may loose the split fat sign.
7. The nidus of an osteoid osteoma may not be visible. Occasionally not painful and not hot on bone scan.
8. A fibrolipomatous hamartoma of the median nerve ca be associated with macrodactyly.
9. Although the Lauge Hansen classification of ankle injuries is useful because it describes the mode of injury, which is useful when it comes to how to reduce the fracture, it should be rembered that it is the reverse of what actually happens. ie LH describes movement of the foot on the leg when in fact the foot is fixed at the time of injury and the leg moves.
10. Only the superficial ligaments attach to the anterior colliculus of the medial malleolus. The deep ligaments attach to the posterior colliculus and inter collicular grove.
11. Bicruciate ligament tears suggest a knee dislocation. An arteriogram is only indicated if the ankle brachial index is less than 0.8
March 1st (St. Davids day, patron saint of beloved Wales) 2002
1. It can be difficult to distinguish a displaced flap tear from a thickened coronary ligament adjacent to the medial aspect of the tibia.
2. Non operative Rx for first time patella dislocation is as good as operative repair.
3. The meniscofemoral ligament of Humphry is not as important as Wrisberg.
4. The anterior transverse meniscal ligament is present in 58% of people. The posterior transverse meniscal ligament is present in 1-4%, as is the medial or lateral oblique meniscal ligament. The oblique ligaments are named for their anterior attachments, and pass back between the ACL and PCL to the posterior opposite meniscus.
5. A disruption of the superior popliteal meniscal ligament may be associated with lateral meniscal tears.
6. Stenner's lesion is when a torn ulna collateral ligament at the thumb MCPJ comes to lie superficial to the adductor aponeurosis, and is an indication for surgical repair.
7. The widening of the femoral neck with multiple hereditary exostosis can be a modeling deformity rather than due to the presence of an exostosis.
8. If you see what looks like Paget's in the under 30s, consider familial essential osteolysis.
9. Bad prognostic indicators in SONK: large size > 9*19mm, persistent low siganl on T2, oedema and insufficiency Fx.
10. Hemophilia affects the ankle and posterior subtalar joint, but spares the mid foot, unlike juvenile idiopathic arthritis (new name for JRA).
11. Gluteus maximus HAD is often symptomatic.