MSK Flashcards
Macrodystrophia lipomatosa
rare form of localised gigantism
painless enlargement of the 2nd or 3rd digit of the hand or foot. It is usually unilateral but may involve adjacent digits in the distribution of the median or plantar nerves
What other injury is associated with perilunate dislocation?
scaphoid fracture
What ages do you see physiologic periostial reaction?
1-6 months
Infant has more than usual physiologic periosteal reaction, diffusely - what is it from?
prostaglandin treatment to keep ductus arteriosis patent
Ddx of periosteal rxn in an infant:
Prostaglandin therapy, Caffey’s disease, congenital syphilis, hypervit. A, multifocal osteomyelitis, lymphoma/leukemia
What’s Caffey’s disease?
infantile cortical hyperostosis a largely self-limiting disorder which affects infants. It causes bone changes, soft-tissue swelling, and irritability
The mandible, ulna and clavicle are most common sites
Radiation therapy, what do you worry about 10-40 years out?
Radiation induced sarcoma
Soft tissue calcification ddx:
Dystrophic (amorphous, may ossify) CPPD (usually in cartilage) *metastatic Ca2+ (elevated Ca2+ levels) Tumoral calcinosis (fluffy, periarticular) metastatic osteosarc primary soft tissue sarcoma Sarcoid
Ddx for dystrophic calcification in soft tissues:
post-traumatic (heterotopic ossification) scleroderma cistercercosis (or other parasite) osteosarc hyper Vit. D dermatomyositis Venous insufficiency
Causes of elevated serum Ca2+
primary hyperparathyroidism, chronic renal disease, milk-alkali, hyper Vit. D, widespread bone destruction
hip pain in a 12 year old
Slipped Capital Femoral Epiphysis
early - widened epiphysis
late - capital slips posterioinferomedially
Flowing syndesmophytes, no sacral involvement =
DISH (Diffuse Idiopathic Skeletal Hyperostosis)
Severe destruction/derangement of a joint - think… What might be the cause in the upper extremity?
Neuropathic joint
upper extremity: syringomyelia
otherwise, usually diabetes
Name findings of renal osteodystrophy
osteomalacia:
2ndary hyperpara: subperiosteal bone resorption, soft tissue calcs, brown tumors (eg ribs, hands), sclerosis (rugger jersey spine, salt and pepper skull)
What is cherubism?
progressive fibrooseous lesions of mandible and maxilla in childhood, some think related to fibrous dysplasia
What syndromes are occasionally seen with polyostotic fibrous dysplasia?
McCune-Albright (also has precocious puberty and cutaneous pigmentation)
Mazabraud (soft tissue myxomas, increased risk of malignant transformation)
What’s the syndrome of polyostotic fibrous dysplasia and soft tissue lesions? What are the lesions? What’s the concern?
Mazabraud. Soft tissue myxomas.
Increased risk of malignant transformation.
Differential for multiple lucent bone lesions:
Fibrous dysplasia LCH Mets, myeloma hyperpara (brown tumors) infection
What’s the order of appearance of ossification centers in the elbow?
Capitellum Radial head Internal (medial) epicondyle Trochlea Olecrenon External (lateral) epicondyle
Infant foot deformity - talus looks vertical
Congenital vertical talus
“opposite” of club foot
causes hindfoot valgus and flatfoot
Ddx for multiple wormian bones
PORKCHOPS: pyknodysostosis *osteogenesis imperfecta rickets kinky hair syndrome *cleidocranial dysostosis hypothyroidism hypophosphatasia otopalatodigital syndrome primary acroosteolysis (Hajdu-Cheney syndrome) pachydermoperiostosis progeria down Syndrome
Partially absent clavicle - what cause?
hyperparathyroidism : subperiosteal bony resorption rheumatoid arthritis : bilateral or unilateral changes with soft tissue swelling, erosion of the outer third of the clavicle scleroderma cleidocranial dysostosis pyknodysostosis (rare) trauma myeloma, mets infection
features of psoriatic arthropathy
bilateral asymmetric, distal joints
erosions, pencil-in-cup, ankylosis, sausage digit
features of achondroplasia
spine: posterior scalloping, narrow interpedicular distance in lower lumbar (stenosis)
Flat, tombstone iliac wings
short, flared bones, esp femur and humerus (rhizomelic)
skull: frontal bossing
trident hands
Gibbus deformity of vertebral body
what’s the significance of “vacuum vertebral body”?
air means it’s a non-neoplastic, non-infectious fracture - nothing there to fill space, so nitrogen gas
Bony features of Marfan syndrome
acetabular protrusion, lumbosacral dural ectasia, pectus excavatum/carinatum
synovial sarcoma features
soft tissue mass near knee or elbow (not in joints, just near them)
can calcify 30%
osteochondral fx of lateral condyle associated with:
ACL tear
features of gout
punched out lytic lesions with overhanging edges, tophi
Erlenmeyer flask deformity:
gaucher, thalassemia, sickle cell, fibrous dysplasia, metaphyseal dysplasia (Pyle’s)
lucent metaphyseal lesion
ABC, UBC, LCH, osteoblastoma, chondromyxoid fibroma, mets, infection, (Giant cell if crosses into epiphysis)
dense metaphyseal band ddx:
Lead poisoning Healing rickets treated leukemia/other systemic illness If multiple: zebra stripe sign of OI Rxd with cyclic bisphosphonates TORCH infxn
lucent metaphyseal band ddx
Rickets
Systemic illness (Leukemia, Neuroblastoma)
TORCH infection
Scurvy
Things to think about with lateral femoral condylar contusion:
ACL disruption
Transient patellar dislocation (look at patella)
Features of reiter’s (reactive) arthritis:
What’s Reiter’s syndrome?
asymmetric in feet (more than hands), erosions, asymmetric SI ankylosis, periostitis - looks like psoriatic but in lower extremity
Syndrome is also urethritis and conjunctivitis
Features of RA (MSK)
soft tissue swelling, osteoporosis juxta-articular,
joint space narrowing (symmetrical or concentric),
marginal erosions, predilection for wrist, MCP, PIP joints. ulnar subluxation
NOT proliferative
Atlanto-axial: subluxation of dens of C2
features of SLE arthritis
subluxations (Jaccoud arthropathy) without erosion
Multiple enchondromas- what is it? What if all on one side? What if soft tissue calcs (and what are these)?
Ollier’s (typically one sided, not inherited)
Soft tissue hemangiomas = Maffucci
(20% malignant transformation to chondrosarc)
Ddx bubbly lucent bone lesions:
FOG MACHINES F : fibrous dysplasia OR fibrous cortical defect (FCD) O : osteoblastoma G : giant cell tumour (GCT) M : metastasis(es) A : aneurysmal bone cyst (ABC) C : chondroblastoma OR chondromyxoid fibroma H : hyperparathyroidism (brown tumour) I : infection (osteomyelitis) N : non-ossifying fibroma (NOS) E : enchondroma OR eosinophilic granuloma (EG) S : simple (unicameral) bone cyst
fracture along medial proximal femur - called what? Indicates what?
Looser’s zone. Symmetric is classic for osteomalacia
Diffuse marrow replacement ddx:
lymphoma/leukemia
diffuse mets
severe anemia (eg Thalassemia)
Ddx epiphyseal lesions
chondroblastoma (and clear cell chondrosarcoma)
geode / intraosseous ganglion
osteosarcoma
LCH (young)
osteoblastoma
(mets, but less)
If growth plates are closed: giant cell tumour (GCT) oraneurysmal bone cyst (ABC - may extend into the epiphysis)
ddx metaphyseal lesions - adult
Mets Osteosarcoma Chondrosarcoma Enchondroma Infection Lipoma Chondromyxoid fibroma (young) ABC - up to 30
What’s the name of an avulsion fracture of the posterolateral tibial plateau? What’s it associated with?
Segond fracture: avulsion fracture of the knee which involves the ileotibial band off the lateral aspect of the proximal tibial plateau, and is very frequently (~75% of cases) associated with ACL tear, and meniscal tear (60%)
What’s the significance of a collar osteophyte around the femoral head?
Ankylosing spondylitis
atrophy of both the supraspinatus and infraspinatus muscles - Ddx?
ganglion expanding into the supraspinous notch brachial neuropathy post trauma Parsonage Turner (acute idiopathic brachial neuritis, can be bilateral)
isolated atrophy of the infraspinatus muscle - where to you look?
spinoglenoid notch (suprascapular nerve)
How do you differentiate JRA from hemophilia on imaging?
MRI: hemosiderin deposition in hemophilia
avulsion of anterior superior iliac spine:
of the inferior iliac spine:
Superior: Sartorius
Inferior: Rectus femoris
What’s the name for inflammation/infection of the fascia? For the muscles?
Necrotizing fasciitis
Pyomyositis (often in diabetics)
Sacral lesion ddx:
chordoma, plasmacytoma, mets, giant cell, teratoma