MSK Flashcards
DDx for acro-osteolysis (PINCH FO)
- Psoriasis, Pyknodysostosis, PVC exposure
- Injuries: frostbite, thermal injury, post traumatic
- Neuropathic: DM, Lesch-Nyhan syndrome
- CVD: scleroderma
- Hyperparathyroidism
- Familial (e.g. Hejdu-Cheney)
- Other (e.g. PVC exposure, progeria)
DDx posterior element bone tumor (Lytic lesion)
- Osteoblastoma
- Osteoid osteoma
- ABC
- GCT
DDx of chondrocalcinosis (“HOGWASH”)
- Hemochromatosis
- Ochronosis
- Gout
- Wilson’s disease
- Acromegaly
- PSEUDOGOUT (CPPD deposition) MCC
- Hyperparathyroidism
What is an Essex-Lopresti fracture?
Comminuted and displaced fracture of the radial head AND subluxation or dislocation of the DRUJ
Due to longitudinal compression force
What is a Monteggia fracture?
Fracture of the ulna and dislocation of the radial head
What is a Galeazzi fracture?
Fracture of the radius at the junction of the middle and distal thirds
Assoc’d subluxation of the distal ulna
What injuries are associated with a Segond fracture?
(avulsion fracture at the insertion of the lateral capsular ligament)
ACL tear
MCL tear/strain
Medial meniscal tear
What is cotton wool skull associated with?
Paget’s disease
What is salt and pepper skull associated with?
Hyperparathyroidism
What are findings in hyperparathyroidism / renal osteodystrophy?
- subperiosteal bone resorption (esp radial aspects of the proximal and middle phalanges of the 2nd and 3rd fingers)
- subligamentous resorption
- subchondral resorption
- rugger-jersey spine
- Brown tumors
- Salt and pepper skull
- chondroclacinosis
- terminal tuft erosion
- osteopenia
In osteochondroma, what thickness of the cartilage cap is suspicious for malignant degeneration?
1.5 cm
What is the chance of malignant transformation for a solitary osteochondroma? MHE?
1%
3-5%
What conditions are associated with H-shaped vertebrae (Lincoln Log appearance)?
- Sickle cell anemia
- Gaucher disease
- Thalassemia
- Spherocytosis
What is associated with picture frame vertebrae?
Paget disease
What is associated with rugger jersey spine?
Hyperparathyroidism
DDX ivory vertebra
- sclerotic metastasis
- lymphoma
- Paget disease
- chordoma
- mastocytosis
DDx lucent lesion in calcaneous
- intraosseous lipoma
- UBC
- GCT
- pseudolesion
DDx lucent lesion in the proximal femur
- intraosseous lipoma
- fibrous dysplasia
- liposclerosing myxofibrous tumor (LSMFT)
- UBC
What is Mazabraud syndrome?
- polyostotic fibrous dysplasia
- multiple soft tissue myxomas (usually in large muscle groups)
What is McCune Albright Syndrome?
- Fibrous dysplasia
- Cafe au lait spots
- Precocious puberty
DDx fluid fluid levels in tumors
- ABC
- GCT
- Telangiectatic osteosarcoma
- Chondroblastoma
- Fibrous dysplasia
What is Ollier syndrome?
Multiple enchondromas
Does not have increased malignant degeneration
What is Maffucci syndrome?
Multiple enchondromas associated with soft tissue hemangiomas
Increased risk of malignant degeneration
What are 4 discriminators for GCT?
1) Epiphyses must be closed
2) Must abut the articular surface
3) Must be well-defined with a non-sclerotic margin
4) Must be eccentric
Some rules do not apply to flat bones
What findings characterize Scheuermann disease?
3 contiguous disc level having:
1) Mild anterior wedging (>5 degrees)
2) endplate irregularity
3) Schmorl nodes
4) kyphosis
DDx for sacral mass
- chordoma
- metastasis
- plasmacytoma
- lymphoma
- sarcoma
- Teratoma
DDx for lesions of the phalangeal tufts
- epidermoid inclusion cyst
- glomus tumor
- foreign body granuloma
- periosteal chondroma
- septic arthritis / osteomyelitis
- brown tumor
DDx for metaphyseal fraying
- healing rickets
- hypophosphatemia
- renal disease
- metaphyseal chondrodysplasia
What are the boundaries of the quadrilateral space?
- teres minor (superiorly)
- teres major (inferiorly)
- humerus (laterally)
- long head of the triceps (medially)
What muscles are involved in quadrilateral space syndrome?
teres minor
+/- deltoid muscle
(axillary nerve affected)
What is Parsonage-Turner syndrome?
aka “acute brachial neuritis”: Refers to an idiopathic denervation of the shoulder.
- Can involve any of the shoulder muscles.
- 97% cases involve the suprascapular nerve.
DDx madelung deformity
“HITDOC”
- Hurler syndrome
- Infection
- Trauma (Salter 5)
- Dyschondroestosis
- Osteochondroma (MHE)
- Congenital (Turner’s syndrome)
DDx distal clavicular erosion
“SHIRT Pocket”
RA
Hyperparathyroidism
Post traumatic osteolysis
"SHIRT Pocket" Scleroderma HPT Infection (osteomyelitis) RA Trauma Progeria
What are the types of psoriatic arthritis?
- Symmetric
- Asymmetric
- Distal interphalangeal predominant (DIP) psoriatic arthritis
- Spondylitis
- Arthritis mutilans
DDx for Erlenmeyer flask deformity
CHONG
Craniometaphyseal dysplasias (e.g. Pyle disease)
Hemoglobinopathies (sickle cell, thalassemia)
Ostopetrosis
Niemann-Pick disease
Gaucher disease
DDx for osteonecrosis
- Sickle cell disease
- Corticosteroids
- Idiopathic
- Gaucher disease
- Trauma
- Alcoholism
- Collagen vascular diseases
- Renal transplantation
- Pancreatitis
What age groups are affected by transient osteoporosis?
pregnant women (3rd trimester) middle aged men (40-55 yo)
What muscles does the suprascapular nerve supply?
supraspinatus
infraspinatus
DDx of extensive soft tissue calcification “TIC MTV”
Tumoral- neoplasm, tumoral calcinosis Inflammation- CVD, infection (parasites) Congenital- Myositis ossificans progressiva, Ehlers Danlos Metabolic- HPT, CPPD, DM Trauma- dystrophic, burn, MO Vascular
Dermatomyositis Polymyositis Mixed connective tissue disease (calcinosis universalis) Scleroderma Burns Calcific myonecrosis Tumoral calcinosis Hemangiomatosis Parasitic infection
What are the radiographic features of chronic tophaceous gout (7)?
- Tophi
- Normal mineralization
- Joint space preservation
- Punched out juxta-articular erosions with sclerotic borders
- Overhanging edges
- Asymmetric polyarticular distribution
- Distribution in feet, ankles, knees, hands, and elbows (decreasing frequency)
DDx intra-articular mass of the knee
PVNS (Localized)
Synovial hemangioma
Synovial chondromatosis
Synovial sarcoma
DDx for synovial hypertrophy and bone erosions
PVNS Synovial osteochondromatosis Amyloid arthropathy TB Synovial hemangiomatosis
What is Preiser’s disease?
Idiopathic AVN of the scaphoid
What is the normal thickness of the plantar fascia?
Shouldn’t exceed 4 mm
DDx concentric hip narrowing
- RA (seropositive), JIA
- Ankylosing spondylitis (seronegative)
- (CPPD, gout)
- Paget’s
DDx for multiple lucent bone lesions (FEEMHI)
- Fibrous dysplasia (McCune Albright vs. Mazabraud)
- Enchondroma (Ollier vs. Maffuci)
- Eosinophilic granuloma
- Mets/Myeloma
- Hyperparathyroidism (HPT with Brown tumors)
- Infection
DDx epiphyseal lesions
- Chondroblastoma
- Infection
- GCT
- Geode (subchondral cyst)
DDx sacroiliits
Psoriatic arthritis Ankylosing spondylitis IBD associated arthritis Reactive arthritis Septic joint (unilateral)
What is de Quervain’s tenosynovitis?
Tendinitis and tenosynovitis of the APL and EPB (first extensor compartment).
Occurs at or just proximal to the radial styloid process.
What is Chopart’s joint?
Mid-tarsal joints (e.g. calcaneocuboid joint and talonavicular joint)
What are causes for AVN (e.g. of the hip)?
- Trauma
- Corticosteroids
- Sickle cell disease
- Lupus
- Idiopathic
- Caisson disease
- Radiotherapy
- Pancreatitis
What is Kohler disease?
AVN of the navicular, typically in children.
In adults, osteonecrosis of the navicular is called Mueller Weiss syndrome.