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
Multiple osteomas of the skull and long bones =
Gardner syndrome (FAP, osteomas, desmoid tumors, duodenal tumors) -look for colonic polyps
What’s the shiny corner sign? What does it signify? What should you look for?
Early ankylosing spondylitis - look for sacroiliitis
What are numerous lesions sticking out of the bone (continuous with the bone marrow)?
Hereditary multiple exostoses/osteochondromatosis (osteochondromas, not to be confused with enchondromas)
There is a 5-25% risk of malignant transformation
lace-like lesion in hand or foot =
sarcoid
fatty replacement of a large (unilateral) group of muscles =
polio (could be some other neuromuscular do)
rheumatoid arthritis in the c-spine:
odontoid erosion atlantoaxial subluxation basilar invagination disc narrowing without osteophytes endplate irregularity and/or sclerosis subluxation at multiple levels
What should you think of when presented with unilateral sacroiliitis
Infection or neoplasm
What’s the likely etiology of a patellar lesion in the superolateral aspect?
normal variant - dorsal defect, bipartite
If you’re thinking of joint sepsis but the aspirate is negative, what could it still be?
TB
lambdoid suture defect ddx
NF1 (leptomeningeal cyst, epidermoid cyst)
radial fracture with ulnar dislocation =
galeazzi fracture
proximal ulnar fracture with radial head dislocation =
Monteggia fracture
What’s the Mickey Mouse sign? What disease?
Uptake in the pedicles and spinous process on a bone scan, indicates Paget’s disease
What’s SAPHO syndrome?
S : synovitis A : acne P : pustulosis H : hyperostosis O : osteitis sternoclavicular joint, long bones, spine some lump this with CRMO
HAGL lesion =
Humeral Avulsion of the Glenohumeral Ligament (if bony, then BHAGL)
axillary nerve damage affects what muscles?
Teres minor and part of deltoid
Ddx metaphyseal lesion in child
NOF Simple Bone Cyst CMF Osteosarcoma Enchondroma infections LCH
Ddx smooth periosteal reaction
hypertrophic osteoarthropathy (pulmonary lesion)
vascular insufficiency : expecially venous stasis (Periosteal reaction due to venous stasis is typically solid and undulating, and initially separated from the cortex)
thyroid acropachy (feathery)
pachydermoperiostitis
fluorosis
Ddx diffusely dense / sclerotic bones
Mets, myelofibrosis, mastocytosis, osteopetrosis, sickle cell, pyknodysostosis, renal osteodystrophy, fluorosis
What’s the calcification pattern in myositis ossificans?
Should you biopsy it?
Peripheral calcification in a large muscle with eventual laminar bone
Don’t biopsy - can be confused with osteosarcoma
Ddx acro-osteolysis:
*scleroderma
*pyknodysostosis (dense bones)
primary acroosteolysis - Hajdu-Cheney syndrome
psoriatic arthritis
*hyperparathyroidism
polyvinyl chloride exposure (bands)
thermal injury (frost bite, burns)
juvenile chronic arthritis (JCA/JIA)
dermatomyositis
vascular occlusion
Raynaud disease
tuft/distal phalanx lysis of a single digit
- epidermal inclusion cyst
* glomus tumour of digit
What’s Klippel-Trenaunay-Weber?
syndrome combination of capillary malformations, soft-tissue or bone hypertrophy, and varicose veins or venous malformations. Triad of:
port wine nevi
bony or soft tissue hypertrophy (localised gigantism)
venous malformations
What’s the ddx of bones with linear / streaky densities?
osteopathia striata congenital infection (rubella, syphilis, CMV) aka celery stalk
What’s Madelung deformity? What causes it?
Abnormality of the ulnar side of the radial growth plate, leads to deformity of the wrist.
Can be congenital (but not manifest until mid childhood), or caused by trauma to growth plate. 50-66% bilateral.
Many associations, including Turner syndrome and Ollier’s disease
rice grain calcifications in the soft tissues are most characteristic of
cistercercosis
What’s the difference between primary and secondary synovial chondromatosis?
Primary is self-limited neoplastic proliferation of synovial nodules, sometimes calcify and if they do, are uniform in size
Secondary associated with trauma and osteoarthropathy - some abnormality of the joint - and tends to cause non-uniform loose bodies
Anterior tibial bowing - thick cortex:
…thin cortex:
Thick (saber shin): congenital syphillis, rickets, yaws (Treponema pallidum)
Thin: NF1 (also get pseudoarthrosis)
what’s the most severe c-spine fracture and its mechanism?
Flexion teardrop - high force, often results in quadripelegia (e.g. diving into shallow water)
Patient has bilateral calcalneal fractures - what do you do?
Image the spine for fractures!
Lesser trochanter fracture - what do you do next?
Get an MRI - almost certainly pathologic
Ddx for macrodactyly
Macrodystrophia lipomatosa NF1 Proteus syndrome Klippel-Trenaunay-Webber Hemihypertrophy - Beckwith-Weidemann
what inserts at the ischial tuberosity?
At the greater trochanter?
At the lesser trochanter?
Ischial tuberosity: hamstrings
Greater trochanter: Gluteus medius
Lesser trochanter: ileopsoas (always pathologic to have avulsion here)
Ddx anterior tibial lucent lesion
Fibrous dysplasia, adamantinoma, ABC
Flared metaphyses:
Rickets, anaemia(s), fibrous dysplasia, storage diseases, chronic lead poisoning
bone dysplasias
Ddx vertebra plana in child:
LCH, mets, gaucher, lymphoma, leukemia, (TB, trauma, OI)
Ddx vertebra plana in adult:
Trauma/osteopenia, mets, myeloma, lymphoma/leukemia, osteomyelitis/TB
(LCH if young)
Bone lesions with fluid-fluid levels:
ABC (primary or 2/2 GCT, NOF, chondroblastoma, fibroxanthoma)
Telangiectatic osteosarcoma
Causes of AVN of the hip
Sickle cell, steroids, trauma
Child: Legg-Calve-Perthes, mucopolysacharidosis
tendon-related tumors
Giant cell tumor of the tendon sheath (histo is same as PVNS) synovial cell sarcoma (may appear benign) ganglion cyst (cystic) hemangioma of tendon sheath (flow voids)
What are the most common foot coalitions?
talocalcaneal (C-sign): middle facet
calcaneonavicular (anteater sign)
Dx for muscle edema in a diabetic
Diabetic myonecrosis
Do not touch - poor vascular supply, will cause an abscess
At the knee, there is a deep lateral femoral notch on lateral view - what is it? What else are you worried about?
Deep lateral femoral sulcus sign of an impacted osteochondral fracture
Look for the associated ACL tear
What’s torn if the long head of biceps tendon is out of the groove?
Subscapularis is torn
What’s a medial femoral condylar defect in an older patient probably from/called?
SONK - spontaneous osteonecrosis of the knee (now called subchondral insufficiency fracture)
associated with meniscal tear
Looks like osteochondritis dessicans, but happens in older patients (~over 55)
What’s the significance of subchondral lucency of the talar dome after a fracture?
Hawkins sign - it’s good and indicates healing a few weeks out. Its absence (relative density) means AVN and non-healing.
What conditions predispose toward Achilles tendon tear?
Steroid injection, DM, inflammatory (RA, SLE), gout
Marked subperiosteal lifting in child or infant
Scurvy - subperiosteal hemorrhage
Causes of acetabular protrusion
Paget's disease Marfan syndrome, Turner's arthropathy: psoriatic arthropathy, RA, ankylosing spondylitis, JIA osteomalacia / rickets OI
Ddx widened pubic symphysis
Trauma, cleidocranial dysostosis, bladder extrophy, prune belly, OI, hypothyroidism
Features of thanatophoric dwarfism
(rhizomelic) and lethal! short, telephone handle femurs small, rectangular iliac wings platyspondyly cloverleaf skull, large head/frontal bossing,
Features of Jeune syndrome
aka asphyxiating thoracic dysplasia - a lethal dwarfism
Long, narrow chest
rhizomelic shortening of limbs
cystic renal disease
Pt cannot lower/abduct arm - what’s happened?
Luxatio erecta - inferior shoulder dislocation (least common type)
High risk of vascular, nerve, tendon and ligament injuries
What’s an avulsion fx of proximal fibula called? What attaches here? Any associated injuries?
Arcuate sign - insertion of the arcuate ligament complex (LCL, arcuate, often biceps femoris, others)
PCL tear very commonly associated
Ddx syndactyly
Apert (can't get my fingers/toes apert! - ask to see head for coronal synostosis = harlequin eyes) Trisomies amniotic bands VACTERL (many others)
osteochondroma of the epiphysis =
Trevor disease (trevor is lever in the end of the bone)
cyclops lesion of knee = ?
caused by?
arthrofibrosis
prior ACL repair
Surface osteosarcomas - describe types
Parosteal (far-osteal) osteosarcoma is trying to get FAR away - small connection to bone
Periosteal osteosarcoma tends to wrap around the bone
Congenital elevation of the scapula - discuss
Sprengel deformity
Often has omovertebral bar (fibrous/cartilaginous/osseus) to cervical spine
Associated with Klippel-Feil (cervical vertebral body fusion)
Name the avulsion fractures around the knee:
Segond (posteriolateral tibia)
arcuate ligament (top of fibula)
reverse segond (medial tibia)
ACL and PCL avulsions
Iliotibial band avulsion (anterolateral tibia)
biceps femoris avulsion (lateral fibular head)
Ddx ivory vertebral body - adult
Infection, blastic mets (prostate, breast), lymphoma, Paget’s
Injuries of concern following anterior shoulder dislocation
Hill-Sachs (ant humerus)
Bankart, bony bankart
ALPSA (anterior labroligamentous periosteal sleeve avulsion) where periosteum is stripped from glenoid
What is SLAC wrist? Causes?
Scapholunate advanced collapse:
Trauma (scapholunate dissociation)
CPPD
Shepherd’s crook deformity classically assoc.:
Fibrous dysplasia
Describe locations and consequences of suprascapular nerve injury:
Suprascapular notch: supra and infraspinatous muscles affected Spinoglenoid notch (just lateral to spine) - infraspinatous only
Degloving injury aka
Morel-Lavallee - subq hematoma
Tumor in intertrochanteric region of femur - be sure to include:
Liposclerosing myxofibrous tumor - benign lytic lesion with sclerotic margin, may be mildly expansile
Fibrous dysplasia is in Ddx
MSK manifestations of NF1
tibial bowing and/or pseudoarthrosis Sphenoid wing dysplasia scoliosis and vertebral body scalloping lamboid suture defect plexiform neurofibromas in the soft tissues skin nodules
Hand and foot findings in sickle cell
Hand-foot syndrome / dactylitis caused by blockage of small vessels Expanded bones periosteal rxn bone infarcts/growth disturbances
Ossific fragment at the medial aspect of medial femoral condyle
Pellegrini Stieda: from old injury of MCL (at medial femoral condyle) which may be from avulsion injury which later calcifies
What’s little leager’s elbow?
separation and fragmentation of the medial epicondylar apophysis in the elbow
What’s Milwaukee shoulder?
Due to hydroxyappetite deposition (often Hx of trauma)
resembles a neuropathic joint, with advanced articular surface destruction with intraarticular loose bodies, subchondral sclerosis, soft tissue swelling and rotator cuff disruption
Hand (or other) film: severe erosive changes, soft tissue lesions, esp in DIP joints, looks like Gout and/or arthritis mutilans
Multicentric histiocytosis (may mention cutaneous lesions as well). Rare disease.
Symmetric sacroiliits:
Asymmetric sacroiliitis:
Symmetric: ankylosing spondylitis, IBD, Whipple
Asymmetric: psoriasis, Reiter’s (reactive), gout, RA, osteoarthritis
What’s associated with osteitis pubis?
psoriatic arthritis
infection
hyperparathyroidism
also trauma, pregnancy/childbirth
chance fracture =
spine fracture that extend all the way through the spinal column (spinous process, pedicles, and vertebral body)
usually lap seat belt injury
Ddx short 4th metacarpal
idiopathic post-traumatic post-infective (e.g. osteomyelitis, yaws, tuberculosis dactylitis) Turner syndrome pseudohypoparathyroidism pseudopseudohypoparathyroidism basal cell naevus syndrome - Gorlin syndrome sickle cell (infarction) hereditary multiple exostosis homocystinuria
Ddx chondrocalcinosis
the “C”s
Calcium (hyperparathyroidism including renal osteodystrophy)
Crystals (CPPD, gout, pseudogout)
Cartilage damaging things: hemochromatosis, aging/OA, ochronosis (blue - alkaptonuria)
