MSK viva Flashcards
Enchondroma v chondrosarc
Size Cortical breach Endosteal scalloping > 2/3 cortical thickness Soft tissue beyond bone Permeative appearance Outside hands and feet, sarc more common Bone scan uptake more common if sarc Age Pain
Lipoma v liposarc
Inhomogeneous with significant soft tissue in the fatty mass - may still be benign but can’t differentiate
Poorly defined adjacent structures
Calcification (present in 11% of lipoma but more common in low-grade sarc)
Infiltration or invasion of mediastinum
Thick (>2mm) / nodular septa, enhancement
Growth
Persisent high T2 on FS T2
Fibrous dysplasia
Non-neoplastic congenital Defective osteoblast differentiation Fibrous stroma and immature woven bone Associated with McCune-Albright, Mazabraud, isolated endocrinopathy, mostly hypers Ribs most common monoostotic Polyostotic commonly unimelic Ground glass, well circumscribed, no periosteal reaction. May endosteal scallop. May be completely lytic or sclerotic May be bubbly cystic
Rind sign - lesion surrounded by thick sclerotic bone
Shephards crook - coxa vara of proximal femur, classically in FD but non-specific
Heterogeneous MR, increased bone scan uptake
Rare malignant degeneration
Differential: osteofibrous dysplasia / ossifying fibroma and adamantinoma - tibia
Cemento-ossifying fibroma - jaw
Lunate dislocation, perilunate
.1 - scapholunate dissociation
2 - perilunate dislocation (majority dorsal - volar rare)
3 - mid-carpal dislocation (triquetrum or lunotriquetral also involved)
4 - lunate dislocation
Stress fractures
Fatigue and insufficiency fractures
Neck of 2-4 metatarsals
Anterior tibia
Sclerosis, cortical thickening, periosteal reaction
Increased NM uptake 3 phase, focal, fusiform or oval, non-specific
DD shin splint - posteromedial distal 2/3 of tibia, soleus insertion, normal blood flow and pool, linear delayed uptake
Accessory navicular syndrome
.Type 2 accessory navicular (fibrous union to navicular) is painful
MR oedema in both
Meniscal tear
Horizontal (parallel to tibial plateau), longitudinal, or radial
Bucket handle is a displaced longitduinal tear
High signal, to articular surface, seen on at least 2 slices
If does not extend to articular surface may just be degeneration (adult) or vascularity (child)
Double PCL sign
Tumoral calcinosis
1/3 familial, AD More common in blacks Painless periarticular masses Hip, shoulder, elbow, foot, wrist Amorphous, multilobulated, cloud-like periarticular calcs.
GLAD, SLAP, ALPSA, Perthes - meanings
Glad - glenolabral articular disruption lesion
Slap - superior labral anterior posterior tear
Alpsa - anterior labroligamentous periosteal sleeve avulsion
Perthes - tear to anterior inferior labrum, lifted from glenoid
ABER view makes labral tears more conspicuous on arthrogram (abduction external rotation - hand on head)
Liposclerosing myxofibrous tumour
AKA polymorphic fibro-osseous lesion of bone
Rare, benign
Prediliction for intertrochanteric region
Slightly more common in males, 30-40
Geographic lucent lesion, sclerotic margin, matrix calc, mildly expansile, multilocular, fat density component
T1 iso to muscle, T2 some bits of high (myxoid)
May have malignant degeneration to osteosarc
Differential: fibrous dysplasia (less sclerosis), lipoma, ABC (more expansile)
Achondroplasia
Narrow foramen magnum Frontal bossing Posterior vertebral scalloping Progressive decrease in interpedicular distance Short pedicle canal stenosis (along with decreased pedicle distance and superimposed degeneration) Metaphyseal flaring - trumpet bone Horizontal acetabular roof Small iliac wings Champagne glass pelvic inlet
Jaccoud arthropathy
Non-erosive subluxing arthopathy of MCPJs
SLE
Originally described in rheumatic fever
Sacral pelvis
SPACE MONGREL Sarcoma (osteo, chondro)/SC teratoma Plasmacytoma ABC Chordoma Ependymoma Mets Osteomyelitis Neuroblastoma GCT Rectal Ewings Lymhoma / leukaemia
Or CAN Chordoma, chndrosarcoma ABC, GCT NF And always mets, myeloma.
Ankylosing spondylitis
Associated with upper lobe predominant interstitial lung disease, and cystic spaces
Symmetric, bilateral SI joint involvement
Vertebral body squaring
Bamboo spine, dagger spine
Shiny corners - healing reactive sclerosis of Ramonos lesions
Romanos - erosion of anterior and posterior edges of vertebral endplates
Andersson - non-infectious spondylodiscitis
Enthesophytes
Spinal ligament ossification
Sacroiliitis
Seronegative spondyloarthropatheis
Symmetric - ank spond, IBD
Asymmetric - Reiters, Psoriatic
Osteosarcoma
MR for local staging for limb-sparing surgery - skip lesions
CT chest and bone scan for distant staging
Talk about staging…
And types and how malignant…
Achilles tendinopathy / retrocalcaneal bursitis
Retrocalcaneal bursitis may be seen in infection, inflammation (arthritis), tendon injury or osis
Decreased lucency in Kager triangle
Often associated with Haglund deformity
Lateral condyle fracture and other paeds elbow patterns
Supracondylar 60%
Lateral condyle 10-20%
Medial epicondyle 10%
Lateral condylar fractures mostly non-displaced
Medial - widening of growth plate and soft tissue swelling - comparison with opposite side may be useful
Osteogenesis imperfecta
Genetic disorder of collagen type 1 production
Osteoporosis with fragile bones, blue sclera
Most are AD, but with different types, can be AR or sporadic
Mild (1), perinatal lethal (2), progressive deforming (3)
Basilar invagination, wormian bones, platyspondyly, codfish vertebrae, pectus, acetabular protrusio, coxa vara, gracile bones
Diaphyseal aclasis
AD with incomplete penetrance in females
Complications: vascular and neural impingement, fracture, bursitis, malignancy,
Cartilage cap >1.5cm suspicious, along with growth and pain after skeletal maturity
Can be sessile or pedunculated
Madelung deformity
Premature closure of distal radial physis Bowed radial shaft, palmar and ulnar tilt of carpus, positive ulnar variance Associations: Achondroplasia Trauma Idiopathic Turners Olliers Hurlers MPS Diaphyseal aclasis Nail-patella (AD, absent nails, hypoplastic pateallae, radial heads/capitella, posterior iliac horns (Fongs prongs) Leri-Weill (mesomelic dwarfism, AD)
Patella dislocation, MR
Lateral dislocation
Medial retinacular injury
Medial patellar and lateral femoral condyle bruising
Sliver sign - intraarticular osteochondral fragment in the knee joint on plaing radiograph
Patealla alta predisposes - long tendon
Peripheral nerve sheath tumour
Benign majority
Higher rate of malignancy in association with NF1
Nerve goes in and out of mass
Muscles supplied by nerve may show denervation changes
Split fat sign - fine rind of fat around lesion
Fascicular sign - small ring like structures with peripheral hyperintensity on T2 (fascicles of the nerve)
Target sign (mostly in neurofibroma but also others, High T2 around collagenous stroma)
Imaging unreliable to differentiate malignant and benign - the larger it is the more likely it i malignant, irregular borders and rapid growth
ACL rupture, plain film
Lateral sulcus sign - depression on lateral condyle at notch between tibial and patellar articular surfaces (terminal sulcus) - from hyperextension or impaction (this is where there is bone brusing also on MR. The normal depth is <1.5mm)
Segond
Arcuate (fibula tip)
Anterior tibial translocation / anterior drawer
Klippel Feil
Two or more non-segmented cervical vertebrae
Female predominant
Associated with Sprengel deformity, renal anomalies (VACTERL)
Sprengel deformity
Congenital elevation of scapula
An omovertebral bar is often present (may be fibrous or osseous
UBC
Benign lucent intramedullary metaphyseal
(note ABC and GCT are eccentric - and are both posterior element lesions - can have UBC of posterior elements)
Can rarely be seen in talus, calcaneus, iliac wing
Sclerotic margin
May have fallen fragment sign
