CORE - MSK Flashcards
1
Q
Widened intercondylar notch + epiphyseal overgrowth (knee)
A
hemophilia, JIA
2
Q
Kummel disease
A
gas in a vertebral body compression fracture; represents osteonecrosis
3
Q
Shoulder arthrogram needle location
A
inferior-medial humeral head (at the GH joint)
4
Q
Hip arthrogram needle location
A
lateral femoral head (at head-neck junction)
5
Q
Posterior hip dislocation on AP radiograph
A
femoral head displaced superiorly and slightly lateral (in addition to posteriorly)
6
Q
Anterior hip dislocation on AP radiograph
A
femoral head displaced inferiorly (most commonly); lesser trochanter is also more visible due to external rotation
7
Q
Osteitis condensans ilii
A
benign sclerosis of the ilium adjacent to the SI joints; typically bilateral, triangular shape, joint space is normal
8
Q
Hereditary hyperphosphatasia
A
a.k.a. juvenile Paget’s; AR; affects infants/toddlers; diffuse involvement of all bones
9
Q
Osteopoikolosis
A
AD; periarticular; mild arthralgias, increased keloid formation
10
Q
Spontaneous pneumothorax in an osteosarcoma patient
A
lung metastasis
11
Q
Fracture healing time (general + fastest/slowest)
A
6-8 weeks generally; phalanges heal in 3 weeks (fastest), tibia heals in 10 weeks (slowest)
12
Q
Delayed union (fracture)
A
fracture not healed within twice as long as expected
13
Q
Non-union (fracture)
A
fracture not healed within 6-9 months; not going to heal without intervention
14
Q
Mal-union (fracture)
A
fracture healed in poor anatomic position
15
Q
Risk factors for improper fracture healing
A
Vitamin D deficiency, gastric bypass patients
16
Q
1st and 2nd most common carpal bone fractures
A
scaphoid > triquetral; 70% of scaphoid fractures occur at the waist
17
Q
First sign of AVN in scaphoid fracture
A
sclerosis; proximal scaphoid fractures are most susceptible to AVN (T1 dark)
18
Q
Most important band of scapholunate ligament for carpal stability
A
dorsal band
19
Q
DISI deformity is associated with injury to what ligament
A
scapholunate ligament; lunate rotates dorsally with triquetrium; more common type of -ISI deformity
20
Q
Degenerative changes of radioscaphoid joint
A
consider SLAC or SNAC
21
Q
Causes of scapholunate ligament injury
A
FOOSH, osteoarthritis, CPPD; may progress to SLAC wrist
22
Q
Measurement for scapholunate ligament injury
A
> 3 mm widening (worse with clenched fist view)
23
Q
Perilunate dislocation association(s)
A
60% assoc. with scaphoid fracture; capitate dislocates dorsally
24
Q
Midcarpal dissociation association(s)
A
lunotriquetral ligament injury, triquetral fracture; capitate dislocates dorsally, lunate rotates volar
25
Lunate dislocation association(s)
occurs with dorsal radiolunate ligament injury
26
Space of Poirier
interval between capitate and lunate with poor ligamentous support; assoc. with perilunate dislocation/instability
27
Lesser arc vs. greater arc injuries (wrist)
lesser arcs injuries are purely ligamentous, greater arc injuries are assoc. with fractures
28
VISI deformity is associated with injury to what ligament
lunotriquetral ligament; lunate rotates volarly with scaphoid; Ulnar-sided injury (TL lig.) is VISI ('U' sort of looks like 'V')
29
DISI and VISI scapholunate angles
VISI is <30 degrees, DISI is >60 degrees; normal is 30-60 degrees
30
Bennett vs. Rolando fractures
Rolando is comminuted; both involve base of 1st metatarsal
31
Cause of dorsolateral dislocation in Bennett fracture
pull of abductor pollicus longus (APL) tendon
32
Stener lesion
occurs in Gamekeeper's thumb; adductor pollicus tendon gets caught in torn UCL; treatment is surgical
33
Median nerve distribution
volar aspect of hand from thumb to radial aspect of 4th digit
34
Thickening of median nerve +/- adjacent edema
carpal tunnel syndrome; may present with thenar atrophy
35
Carpal tunnel syndrome associations
dialysis, pregnancy, diabetes, hypothyroidism
36
Guyon's canal syndrome
ulnar nerve entrapment in Guyon's canal (formed by pisiform and hamate)
37
Handle bar palsy
Guyon's canal syndrome; may also be caused by hook of hamate fracture
38
Smith fracture
opposite of Colles; distal radial metaphyseal fracture with volar angulation; both are often assoc. with ulnar styloid fracture
39
Barton fracture
intra-articular fracture of distal radius (radial rim); dorsal or volar dislocation of radio-carpal joint (volar more common)
40
Normal volar tilt of distal radius
11 degrees; must have true lateral view to measure
41
Positive ulnar variance association
ulnar impaction syndrome => TFCC destruction + lunate degeneration (possibly cystic)
42
Tendon associated with TFCC
ECU (compartment 6)
43
Capitellum fracture association
posterior elbow dislocation
44
Essex-Lopresti
radial head fracture + dislocation of DRUJ; considered unstable (rupture of interosseous membrane)
45
Causes of cubital tunnel syndrome
accessory anconeus, overuse, humeral fracture, mass lesion; results in thickening of ulnar nerve
46
Best view to see Hill-Sachs (x-ray)
internal rotation
47
Signs of posterior shoulder dislocation
>6 mm between glenoid and humerus, reverse Hill-Sachs (trough sign), locked in internal rotation
48
Inferior shoulder dislocation associations
rotator cuff tear, greater tuberosity injury; 60% get nerve injury (axillary nerve most commonly)
49
Most common location for fibrous dysplasia
ribs
50
Post-op shoulder: glenoid intact + cuff intact
hemi-arthroplasty or resurfacing
51
Post-op shoulder: glenoid intact + cuff deficient
hemi-arthroplasty or reverse arthroplasty
52
Post-op shoulder: glenoid deficient + cuff intact
total shoulder arthroplasty
53
Post-op shoulder: glenoid deficient + cuff deficient
reverse arthroplasty
54
Most common complication of total shoulder arthroplasty
loosening of glenoid component
55
"Anterior escape"
complication of total shoulder arthroplasty; anterior migration of humeral head after subscapularis failure
56
Complication of reverse should arthroplasty
posterior acromion fracture (from deltoid tugging)
57
Classic stress fracture locations
medial femoral diaphysis, medial femoral neck, posterior-lateral tibial shaft
58
Trauma patient with foot/leg locked in internal rotation
posterior hip dislocation
59
Most common type of hip dislocation
posterior (dashboard injury)
60
Acetabular injury with disruption of iliopectineal line
anterior column fracture
61
Acetabular injury with disruption of ilioischial line
posterior column fracture
62
Complication of intracapsular hip fracture
disruption of blood supply (circumflex femoral a.) => AVN; degree of fracture displacement corresponds to risk of AVN
63
Muscle(s) implicated in iliac crest avulsion injury
abdominal muscles (EO/IO/TA)
64
Snapping hip syndrome algorithm
clinical evaluation to r/o external type => x-ray to r/o intra-articular type (degen. changes, loose bodies) => US to r/o internal type (iliopsoas snapping of iliopectineal eminence) => MR arthrogram to r/o intra-articular type (labral tears)
65
Most common type of snapping hip syndrome
external/lateral (IT band snapping over greater trochanter)
66
Most common location for labral tears (hip)
anterior-superior
67
FAI demographics
cam-type = males, average age is 32 y/o; pincer-type = females, average age is 40 y/o; results in early degen. changes
68
Measurement suggestive of cam-type FAI
alpha angle >55 degrees
69
Crossover sign (acetabulum)
pincer-type FAI
70
Coxa profunda vs. protrusio acetabuli
coxa profunda = acetabulum projects medial to ilioischial line; protrusio acetabuli = acetabulum and femoral head project medial to ilioischial line; there may be an association with either type and pincer-type FAI
71
Causes of sacral insufficiency fracture
osteoporosis, renal failure, RA, pelvic radiation, extended steroid use, mechanical changes after hip arthroplasty
72
Reverse segond fracture associations
PCL and medial meniscus injury; occurs due to external rotation (opposite of a segond fracture)
73
Arcuate sign association
PCL injury
74
Patellar tendon tear associations
SLE, RA, elderly, trauma/sports
75
Bilateral patellar tendon tears
chronic steroid use
76
Most common type of tibial plateau fracture
Schatzker type 2 (split and depressed lateral tibial plateau fracture); in general, lateral > medial
77
Salter-Harris type for a juvenile Tillaux fracture
type 3; medial physis fuses before lateral physis
78
Salter-Harris type for a triplane fracture
type 4
79
Maisonneuve fracture
medial malleolar fracture or disruption of distal tibiofibular syndesmosis, + a proximal fibular fracture; unstable
80
Bilateral calcaneal fractures - NEXT STEP
image spine (r/o compression or burst fractures)
81
Bohler's angle concerning for calcaneal fracture
<20 degrees
82
Jones fracture
fracture at base of the 5th metatarsal
83
Causes of 5th metatarsal avulsion fracture
tug from peroneus brevis or plantar aponeurosis (lateral cord)
84
Mechanism of Lisfranc injury
extreme plantar flexion + axial load; cannot exclude on non-weightbearing films; high risk for non-union and post-traumatic arthritis
85
Fleck sign
small bony fragment in Lisfranc space associated with avulsion of the Lisfranc ligament
86
Tensile stress fracture locations in femur and tibia
lateral femoral neck and anterior tibia, respectively
87
SONK
insufficiency fracture, most commonly of medial femoral condyle; "old lady with no history of trauma"
88
SONK association
meniscal injury
89
March fracture
metatarsal stress fracture; e.g. military recruits
90
Most fractured tarsal bone
calcaneus (75% intra-articular)
91
High risk stress fractures
lateral femoral neck, transverse patella, anterior tibia, 5th metatarsal, talus, tarsal navicular, great toe sesamoid
92
Looser zones
insuffiency fractures (pseudofractures) seen in osteomalacia, rickets, osteogenesis imperfecta; femoral neck and pubic rami (classically)
93
Looser zone findings
lucency with surrounding sclerosis; occur at right angles to cortex; often symmetric
94
Most common complication of osteoporosis
insufficiency fracture (spine > hip > wrist)
95
False positive DEXA
laminectomy
96
False negative DEXA
osteophytes, dermal calcifications, metal, compression fracture, too much femoral shaft included (hip)
97
Sudeck atrophy
a.k.a. RSD or CRPS
98
Unilateral severe osteopenia with preserved joint spaces
reflex sympathetic dystrophy; hand and shoulder most commonly
99
Transient osteoporosis of hip findings
osteopenia on x-ray, edema on MRI, hot on bone scan; 3rd trimester female with hip pain classically; self-limited
100
Regional migratory osteoporosis
migratory osteopenia and joint pain; more common in men; self-limited
101
Osteochondral lesion with surrounding high T2 signal
stage 3, unstable; may lead to secondary OA if untreated
102
Panner vs. Kohler vs. Sever vs. Kienbock
Panner = capitellum; Kohler = navicular; Sever = calcaneus; Kienbock = lunate; osteonecrosis, may cause growth disturbance
103
Contents + disease for wrist compartments 1, 3, and 6
1 = APL, EPB (de Quervain's); 3 = EPL (medial to Lister's tubercle); 6 = ECU (tenosynovitis in early RA)
104
Intersection syndrome compartments
proximal is compartments 1 & 2; distal is compartments 2 & 3; classically in rowers
105
Contents of carpal tunnel
4 flexor digitorum profundus tendons, 4 flexor digitorum superficialis tendons, FPL (lateral), median nerve (lateral)
106
Structures that do not go through carpal tunnel
FCR, FCU, FPB, palmaris longus (if present)
107
Communication between ankle joint space and common peroneal tendon sheath
implies tear of calcaneofibular ligament
108
Tenosynovitis of multiple flexor tendons of the hand/wrist
RA (may also present as ECU tenosynovitis)
109
Superficial nodularity along the palmar aponeurosis (distal palm)
Dupuytren's contracture; 50% bilateral
110
T1 dark + T2 bright mass of distal finger
glomus tumor (painful, at nailbed, enhancing) or epidermal inclusion cyst (painless, h/o trauma)
111
T1 dark + T2 dark mass of finger/hand
GCT of tendon sheath (blooming, may erode bone) or fibroma (no blooming); both enhance
112
T1 dark + T2 bright lesion along dorsal wrist
ganglion cyst (dorsal >> volar)
113
Hildreth sign
pain associated with a glomus tumor disappears with a tourniquet
114
Osborne band
a.k.a. cubital tunnel retinaculum or epicondylo-olecranon ligament
115
T sign (elbow)
partial UCL tear; represents gad medial to sublime tubercle (MR arthrogram); seen in throwers (valgus overload)
116
Most important bundle of UCL (elbow)
anterior bundle
117
Low T1 + high T2 signal in the capitellum
Panner disease or OCD; OCD generally occurs in adolesence and may have loose bodies
118
Most common type of epicondylitis
lateral epicondylitis (tennis elbow)
119
Structures involved in lateral epicondylitis
ECRB +/- LCL complex; NOT an avulsion injury
120
Structures involved in medial epicondylitis
common flexor tendon (CFT); may see ulnar nerve thickening; NOT an avulsion injury
121
Dialysis elbow
olecranon bursitis related to constant pressure from arm positioning
122
Epitrochlear lymphadenopathy
consider cat scratch disease
123
Causes of external impingement resulting in supraspinatus injury
a.k.a. subacromial impingement; hook acromion (type 3), subacromial osteophytes, os acromiale, thickened coraco-acromial ligament
124
Causes of external impingement resulting in subscapularis injury
a.k.a. subcoracoid impingement; between lesser tuberosity and coracoid; less common
125
Causes of internal impingement (shoulder)
multi-directional glenohumeral instability, posterior-superior type, anterior-superior type
126
Posterior-superior type of internal impingement (shoulder)
infraspinatus and posterior supraspinatus tendons pinched between greater tuberosity and labrum; throwers, swimmers, tennis players
127
Anterior-superior type of internal impingement (shoulder)
subscapularis and biceps tendons pinched against anterior-superior labrum
128
Abnormal signal in rotator interval
adhesive capsulitis; may see loss of fat and/or enhancement in rotator interval
129
Thickening of axillary pouch (shoulder)
adhesive capsulitis; >4 mm thickening; also with decreased glenohumeral joint volume
130
Partial tear thickness requiring surgical intervention (shoulder)
>50%; articular surface tears are more common than bursal surface tears
131
Least common rotator cuff muscle to tear
teres minor
132
SLAP tear type with extension into biceps tendon
type 4; treatment requires debridement + biceps tenodesis
133
Most common type of SLAP tear
type 2; SLAP tears are typically related to over head movements and are NOT considered unstable
134
Sublabral foramen
unattached labrum from 1 to 3 o'clock
135
Absent anterior-superior labrum + thickened MGHL
Buford complex
136
Anterior-inferior labral injury with adjacent articular cartilage injury (shoulder)
GLAD lesion; stable
137
GLAD (acronym)
glenoid labral articular disruption; anterior-inferior superficial labral tear with associated cartilage injury
138
Anterior-inferior labral injury with minimal displacement of intact periosteum (shoulder)
Perthes lesion; unstable
139
Anterior-inferior labral injury with medial displacement of intact periosteum (shoulder)
ALPSA lesion; unstable
140
ALPSA (acronym)
anterior labro-ligamentous periosteal sleeve avulsion
141
Anterior-inferior labral injury with disruption of periosteum (shoulder)
Bankart lesion; unstable
142
Posterior glenohumeral instability lesions
reverse Bankart, POLPSA, Bennett lesion, Kim lesion
143
POLPSA (acronym)
posterior labro-capsular periosteal sleeve avulsion; results in a recess that communicates with joint space
144
Bennett lesion (shoulder)
a.k.a. thrower's exostosis; avulsion of posterior band of IGHL => posterior extra-articular ossification; assoc. with posterior labral injury
145
Kim lesion (shoulder)
incompletely avulsed or flattened posterior labrum; labral-cartilage relationship is preserved
146
HAGL (acronym)
humeral avulsion of the inferior glenohumeral ligament; occurs at humeral attachment of IGHL; unstable
147
HAGL associations
often due to anterior shoulder dislocation; assoc. with subscapularis tendon tears
148
Biceps tendon subluxation vs. dislocation
subluxation is seen with transverse ligament injury; dislocation is seen with transverse ligament + biceps pulley injury
149
Biceps tendon dislocation association
subscapularis tendon tears
150
Avulsion-type partial undersurface tear (shoulder)
PASTA lesion (or "rim rent tear")
151
Partial undersurface tear extending into tendon (shoulder)
PAINT lesion
152
Result of lesion at spinoglenoid notch
distal suprascapular nerve impingement => isolated infraspinatus atrophy
153
Result of lesion at suprascapular notch
proximal suprascapular nerve impingement => infraspinatus + supraspinatus atrophy
154
Result of lesion in the quadrilateral space
axillary nerve impingement => teres minor +/- deltoid atrophy
155
Borders of quadrilateral space
humerus (lateral), teres minor (superior), long head triceps (medial), teres major (inferior)
156
Parsonage-Turner
idiopathic brachial plexus neuropathy; consider when multiple nerve distributions involved (e.g. axillary and suprascapular)
157
Function of ACL bundles
anteromedial bundle tightens knee in flexion; posterolateral bundle tightens knee in extension
158
Conjoint tendon (knee)
formed by LCL and biceps femoris
159
Meniscocapsular separation
separation of medial meniscus and MCL
160
Discoid meniscus - medial or lateral most commonly?
lateral; prone to tears; Wrisberg variant is rare and super prone to tears
161
Bucket handle tear - medial or lateral most commonly?
medial; shown as absent bowtie, double PCL, or double delta signs; double PCL = medial meniscus tear
162
Significance of double PCL sign
can only occur with intact ACL
163
Meniscal ossicle association
radial tear of root of medial mesiscus; ossicle = ossification within posterior horn of medial meniscus
164
O'Donoghue's unhappy triad
ACL tear, MCL injury, medial meniscus tear
165
Contusion pattern associated with ACL tear
lateral femoral condyle + posterior lateral tibial plateau
166
Blumensaat angle >15 degrees
probable ACL tear (normal is <15 degrees); apex of angle pointing inferiorly is also a sign of ACL tear
167
Celery stalk appearance of ACL
mucoid degeneration; predisposes to ACL ganglion cysts
168
Fibular head edema
suggest posterolateral corner injury
169
Contents of posterolateral corner
IT band, biceps femorus, LCL, popliteus tendon; missed PLC injury is a source of ACL reconstruction failure
170
Tibial tunnel placed anterior to Blumensaat's line (ACL repair)
risk of roof impingement; positioning of tibial tunnel is primary factor in preventing impingement
171
Primary factor for maintaining isometry (ACL repair)
positioning of femoral tunnel; isometry = constant length and tension
172
Best view for evaluation of anterior-inferior labrum (MRI)
ABER view; ABER = ABduction External Rotation
173
PCL tear - NEXT STEP
check for popliteal flow void (may need CTA run-off)
174
Patellar dislocation associations
MPFL tear; may be assoc. with trochlear dysplasia (too flat)
175
Increased risk of tear with meniscal flounce?
NOT assoc. with an increased incidence of meniscal tears
176
Fabella location
sesamoid located within lateral head of gastrocnemius; seen posterior to lateral femoral condyle
177
Cyamella location
sesamoid located within popliteus tendon; seen lateral to popliteal groove (femur)
178
Most common accessory muscle of ankle
peroneus quartus (lateral ankle); accessory soleus and accessory FDL are both in medial ankle
179
Insertions of biceps and brachialis tendons
radial tuberosity and coronoid process (ulna), respectively
180
Most frequently injured ankle ligament
ATFL
181
Posterior tibial tendon injury progression
PTT injury => spring ligament injury => flat foot => sinus tarsi syndrome => plantar fasciitis
182
Primary stablizer of the longitudinal arch (foot)
posterior tibialis tendon; acute tears occur near insertion on navicular, chronic tears occur posterior to medial malleolus
183
Acute flat foot
consider PTT tear; may also have hindfoot valgus
184
Split peroneus brevis association
lateral ankle ligament injury; seen with inversion injuries
185
Anterolateral impingement syndrome (ankle)
injury to ATFL/tibiofibular ligaments => lateral instability => chronic synovitis => scarred mass in lateral gutter (low T1/T2)
186
Sinus tarsi syndrome associations
PTT injury, rheumatologic disorders
187
Pain and paresthesias in toes or sole of foot
tarsal tunnel syndrome (compression of tibial nerve); causes are idiopathic, ganglion cyst, NF1, post-calcaneal fracture
188
Loss of plantar flexion
consider Achilles tendon injury; may still be able to plantar flex ankle if a plantaris muscle is present
189
Fusiform thickening of Achilles tendon
Achilles xanthoma (often bilateral); assoc. with familial hypercholesterolemia
190
Plantar fascia thickness suggestive of plantar fasciitis
>4 mm (with adjacent T2 signal); symptoms worsened with dorsiflexion of toes; most commonly involves central band
191
7-10 days
time frame when early osteomyelitis may be occult; also time to repeat x-ray if suspicion for occult fracture
192
Sequestrum
necrotic bone surround by granulation tissue; seen in chronic osteomyelitis
193
Involucrum vs. cloaca
involucrum = living bone surrounding necrotic bone; cloaca = opening in involucrum; seen in chronic osteomyelitis
194
Sequestrum DDx
chronic osteomyelitis, osteoid osteoma (mimic), EG, lymphoma, fibrosarcoma
195
Age when infection can spread from metaphysis to epiphysis via blood
<18 months
196
Initial site of infection in discitis-osteomyelitis - peds vs. adults
peds = intervertebral disc with spread to adjacent bone; adults = subchondral bone with subsequent spread to disc
197
Characteristics of spinal TB
spares disc space, Gibbus deformity, psoas abscess, large paraspinal abscess, skip lesions
198
Septic arthritis of sternoclavicular joint
IV drug users
199
Synovial enhancement + joint effusion
non-specific, but suspect septic arthritis (especially if abnormal periarticular marrow signal)
200
Fournier gangrene
necrotizing fasciitis of the scrotum; nec fasc is most often polymicrobial
201
Spina ventosa
tuberculous dactylitis; seen in kids, expansile lesion with adjacent soft tissue swelling, no periosteal reaction
202
Lesion characteristics associated with increased risk of pathologic fracture
lytic lesion, >3 cm in size, involve >50% of cortex; based on x-ray or CT
203
Osteosarcoma subtype with best prognosis
parosteal (followed by periosteal); secondary osteosarcoma has worst prognosis
204
Fluid-fluid level DDx
telangiectatic osteosarcoma, GCT, ABC; synovial sarcoma or lymphatic malformation if soft tissue mass
205
Causes of secondary chrondrosarcoma
Paget disease, osteochondroma, Maffucci > Ollier
206
52 y/o with chondroblastoma
clear cell chondrosarcoma; chondroblastoma is a pediatric lesion
207
Lytic lesion of bony pelvis DDx (peds)
Ewing's, osteosarcoma, LCH, neuroblastoma met, lymphoma/leukemia, osteomyelitis
208
Lytic lesion of bony pelvis DDx (adult)
chondrosarcoma, mets, myeloma, MFH, lymphoma/leukemia, brown tumor, osteomyelitis; chordoma if midline sacrum
209
Aggressive bony neoplasm with skip lesions
Ewing's
210
Most common location for chordoma
sacrum > clivus > C-spine (C2 most commonly)
211
T2 dark or iso soft tissue mass
MFH/PUS (50% T2 dark/iso); may also have an osseous origin (NO periosteal reaction)
212
Pleomorphic undifferentiated sarcoma
a.k.a. MFH; old people; proximal arms/legs, retroperitoneum; radiation and Paget's are risk factors; may arise from bone infarct
213
Soft tissue mass with spontaneous hemorrhage
MFH; MFH is more common than synovial sarcoma
214
Soft tissue mass near a joint in 30 y/o
synovial sarcoma; 20-40 y/o; "triple sign" or multiple fluid-fluid levels
215
Soft tissue mass with calcifications and adjacent bony erosion in 30 y/o
synovial sarcoma; prefers distal lower extremities (foot, ankle, lower leg)
216
Soft tissue mass with high T2 signal and phleboliths
venous malformation (a.k.a. soft tissue hemangioma); T2 dark phleboliths, enhancing, may contain fat; NO flow voids
217
Soft tissue mass with numerous flow voids
arteriovenous malformation (AVM)
218
Intramuscular mass with high T2 signal +/- low signal septations
intramuscular myxoma; mild enhancement, +/- low signal septations, +/- flame-shaped adjacent high T2 signal
219
Fluid-filled soft tissue lesion with thin enhancing septations
lymphatic malformation
220
Infantile hemangioma
usually not present at birth, natural history is growth then involution in childhood; T2 bright, enhancing, may have flow voids; assoc. with PHACES; do NOT contain phleboliths; this is different than a congenital hemangioma (which is fullly developed at birth)
221
Most common liposarcoma in <20 y/o
myxoid; T2 bright, T1 dark, enhancing components
222
Distal femoral metaphyseal defect/irregularity
a.k.a. cortical desmoid
223
Most common carpal coalition
lunotriquetral
224
Madelung deformity associations
prior trauma, Turner syndrome, Hurler's, achondroplasia, multiple hereditary exostoses
225
Iliac horns
seen in nail-patella syndrome or Fong syndrome ("Fong's prongs")
226
Fused cervical vertebral bodies
Klippel-Feil syndrome, JIA; vertebral bodies may be small in either; may see isolated fusion of posterior elements in JIA
227
Osteogenesis imperfecta type most associated with multiple fractures
type 3; type 1 is most common; type 2 is lethal
228
Intramuscular myxoma association
Mazabraud syndrome (polyostotic FD + multiple myxomas); risk of malignant transformation (of FD)
229
Osteosarcoma vs. Ewing's treatment
both get chemo then wide excision, but Ewing's also gets radiation (chemoradiation)
230
Chondrosarcoma treatment
wide excision only
231
Do Not Touch lesions
cortical desmoid, Pitt's pit (synovial herniation pit), myositis ossificans
232
Bone biopsy considerations
avoid gluteal muscles, avoid communicating bursae, avoid quadriceps tendon, avoid posterior 2/3 of shoulder (axillary nerve)
233
Epiphyseal equivalents
calcaneus, carpals, patella, trochanters, most apophyses
234
"Long lesion a long bone"
fibrous dysplasia; no periosteal reaction; polyostotic <10 y/o, monostotic 20-30 y/o (young people)
235
Anterior tibial lesion with anterior tibial bowing
osteofibrous dysplasia; benign, tibia or fibula; cannot reliably be differentiated from adamantinoma
236
Treatment for adamantinoma
en bloc resection (locally aggressive with risk of metastases); NOT benign
237
"Floating tooth"
EG classically, but broad differential including osteomyelitis and mandibular lesions
238
GCT characteristics
closed physis, abuts articular surface, eccentric, sharply marginated border; usually non-sclerotic rim (not always); risk of malignant transformation
239
GCT treatment
wide excision + arthroplasrty; malignant transformation in 5% (often with lung mets)
240
Secondary ABCs may arise from...
GCT (most common), osteoblastoma, chondroblastoma + other osseous lesions less commonly
241
Fibrous cortical defect vs. NOF
FCD <3 cm, NOF >3 cm; both are fibroxanthomas
242
Jaffe-Campanacci syndrome
multiple NOFs, cafe au lait spots, mental retardation, cardiac malformations, hypogonadism
243
Painful scoliosis (night pain)
osteoid osteoma; apex points away from lesion; lots of adjacent edema; most common location is long bones
244
Lucent lesion in posterior elements DDx
osteoblastoma, ABC, TB
245
Epiphyseal lesion with intermediate T2 signal + thin sclerotic rim
chondroblastoma; NOT T2 bright (vs. other chondral lesions), thin sclerotic rim, adjacent marrow/soft tissue edema, +/- periostitis
246
Intertrochanteric lesion DDx
LSMFT, SBC, lipoma, fibrous dysplasia
247
Multiple osseous lytic lesions DDx
fibrous dysplasia, EG, enchondromas, mets, myeloma, hyperparathyroidism (brown tumors)
248
Lytic osseous lesion without associated periostitis DDx
fibrous dysplasia, enchondroma, NOF, SBC (unless fractured), ABC
249
Heterotopic ossification
a.k.a. myositis ossificans; begins as soft tissue mass => peripheral cortical bone at 6 months (ossification, NOT calcification)
250
Lipohemarthrosis - NEXT STEP
suggestive of an intra-articular fracture; need additional imaging
251
Bilateral distal clavicular osteolysis DDx
hyperparathyroidism, RA, scleroderma; may also be post-traumatic (e.g. weightlifting)
252
Accetabular fracture type involving iliac wing
both column type
253
Haglund syndrome
Haglund deformity + insertional tendinopathy + pre-Achilles bursitis; focal pain at posterior calcaneal tuberosity; "pump bump"
254
Arthrofibrosis (knee)
scarring in Hoffa's fat pad following ACL reconstruction; focal form = cyclops lesion
255
RCC and thyroid mets are classically lytic or blastic?
lytic
256
Most sensitive study for myeloma
MRI; skeletal survery > bone scan (often negative); vertebral body destruction with sparing of posterior elements (classically)
257
"Mini-brain" appearance within a vertebral body
plasmacytoma
258
Myeloma with sclerotic mets
POEMS syndrome
259
Shortened 4th and 5th metacarpals DDx
pseudohypoparathyroidism, pseudopseudohypoparathyroidism, Turner's syndrome
260
High PTH, low calcium, high phosphate
pseudohypoparathyroidism; PTH increases serum calcium and decreases serum phosphate
261
Features of osteochondroma concerning for malignant transformation
cap thickness >1.5 cm, assoc. soft tissue mass, pain; increased risk with MHE
262
Pain associated with an enchondroma or osteochondroma
suspicious for malignant transformation
263
Dysplasia epiphysealis hemimelica
a.k.a. Trevor disease; osteochondromas within epiphyses; ankle > knee
264
Compression of which nerve is associated with an avian spur?
median nerve (compressed by ligament of Struthers); avian spur points towards joint
265
Juxta-cortical chondroma
benign lesion, 10-40 y/o; causes saucerization of external cortex with periosteal reaction; fingers, proximal humerus, distal femur
266
Timing of physiologic bowing
18-24 months; smooth, lateral, bilateral; self-limited
267
Anterolateral tibial bowing
NF1; often with tibial or fibular pseudarthroses
268
Forestier disease
a.k.a. DISH; 4 or more contigous levels of involvement, spares disc space, thoracic spine most commonly; assoc. with OPLL
269
Synovial chondromatosis findings (MRI)
high T2, low T1 intra-articular nodules; often with adjacent bony erosion; malignant transformation is rare
270
Lateral tibial bowing with widening and irregularity of growth plates
rickets, or hypophosphatasia (if neonate)
271
Classic location for OA vs. RA in the foot
OA is 1st MTP; RA is 5th metatarsal head (MTP)
272
Patterns of femoral head migration - OA vs. RA
OA is superolateral or medial migration; RA is axial migration
273
"Surgical-like margins"
neuropathic joint; e.g. due to syringomyelia, spinal cord injury
274
5 D's of neuropathic joints
deformity, debris, dislocation, dense subchondral bone, destruction of articular cortex
275
Felty syndrome
RA + splenomegaly + neutropenia
276
Caplan syndrome
RA + pneumoconiosis; supposedly upper lobe predominant, whereas rheumatoid lung is typically lower lobe predominant
277
Fluffy periostitis + erosions
psoriatic arthritis, reactive arthritis; reactive classically stays below waist
278
Psoriatic arthritis distribution
IPs > MCPs; buzzwords = sausage digit, pencil-in-cup, mouse ears
279
Ivory phalanx
psoriatic arthritis; great toe most commonly
280
Ankylosis in finger DDx
psoriatic arthritis or erosive OA
281
First site of involvement in ankylosing spondylitis
typically SI joints; if you're thinking AS in the spine, but hip joints are shown and normal => it's not AS
282
Minor trauma in patient with DISH or AS - NEXT STEP
whole spine CT
283
Complications of hip replacement in an AS patient
significant heterotopic ossification; often receive post-op prophylactic low-dose radiation + NSAIDs
284
Arthritides that spare joint space
gout, amyloid, SLE/Jaccoud's
285
Findings of gout (MRI)
juxta-articular sharply-marginated erosions with associated low T2 soft tissue mass; tophi typically enhance
286
Gout mimickers DDx
amyloidosis, cystic RA, multicentric reticulohistiocystosis, sarcoidosis, hyperlipidemia
287
Isolated patellofemoral, radiocarpal, or talonavicular disease (arthritis)
CPPD; hook-like osteophytes of 2nd/3rd metacarpal heads; most commonly involves knee
288
Large subchondral cyst formation
consider CPPD (over OA)
289
Uniform MCP joint space loss + hooked osteophytes
hemochromatosis; may also cause chondrocalcinosis
290
Tuft resorption (fingers) with rib notching
hyperparathyroidism; also subperiosteal bone resorption along radial aspect of 2nd/3rd fingers
291
Cause of Milwaukee shoulder
HADD; shoulder destruction with intra-articular loose bodies; history of trauma to affected joint
292
Focal lateral paravertebral ossification
psoriatic arthritis
293
Erosion of dens DDx
CPPD, RA, JIA
294
Ulnar subluxation at MCPs
think RA or SLE/Jaccoud arthropathy
295
Ossification of posterior longitudinal ligament (OPLL) associations
DISH, ankylosing spondylitis, ossification of ligamentum flavum; may cause canal stenosis and predispose to cord injury with minor trauma
296
Age requirement for JIA
<16 y/o; carpal erosions, premature fusion of growth plates
297
Amyloid arthropathy association
chronic dialysis; gout mimic; joint space preserved (until late); may see carpal tunnel syndrome
298
Lymphatic malformation
a.k.a. lymphangioma or cystic hygroma; infants usually; head and neck most commonly; multi-loculated mass following fluid signal with thin enhancing septa; fluid-fluid levels are suggestive; may appear iso-to-high T1 if protein or blood
299
Innominate bone
bone formed by fusion of ilium, ischium, and pubis
300
Soft tissue calcifications DDx
scleroderma, poly- or dermatomyositis, SLE, HADD, myositis ossificans, secondary hyperparathyroidism; chronic renal disease may worsen HADD
301
Most common indication for hip arthroplasty revision
loosening; >2 mm at prosthetic-bone interface is suggestive; component migration is diagnostic
302
Hip arthroplasty with adjacent smooth endosteal scalloping
particle disease; inflammatory reaction to particles shed from arthroplasty surface; most common in non-cemented arthroplasties; may be seen around screw holes
303
Eccentric position of femoral head component within acetabular component (hip arthroplasty)
polyethylene wear (occurs in superior-lateral direction; like OA); "creep" is a normal phenomenon that occurs in the axial direction
304
Stress shielding (hip arthroplasty)
bone resorption in non-weight bearing areas; classically along medial or lateral aspect of proximal femur; medial = calcar resorption; assoc. with non-cemented arthroplasties; increases risk of peri-prosthetic fracture
305
Red marrow in humeral and femoral heads in an adult
normal variant
306
Order of red marrow reconversion
proximal metaphysis => distal metaphysis => diaphysis => epiphyses; spine and flat bones precede long bones
307
Marrow darker than adjacent discs and/or muscle on T1
leukemia; vs. red marrow which is iso to discs/muscle on T1
308
Granulocytic sarcoma
a.k.a. chloroma; destructive mass in bone; occurs in leukemia
309
Secondary causes of calcific tendinitis (HADD)
chronic renal failure, hypervitaminosis D, collagen vascular disease, tumoral calcinosis
310
Calcification of longus colli
due to HADD; neck pain with restricted ROM; may see prevertebral edema on MRI
311
Fusiform enlargement and sclerosis of long bones
Engelmann disease; symmetric, bilateral; often in tibia, may involve skull; hot on bone scan
312
MRI findings of PVNS
blooming, joint effusion, +/- erosions; treatment is synovectomy
313
Synovial chondromatosis
typically mono-articular, most commonly affects knee; loose bodies may eventually ossify; treatment is removal +/- synovectomy
314
Widening of hip joint space (adult)
pituitary gigantism; cartilage will eventually outgrow its blood supply => early OA
315
Lipoma arborescens associations
OA, chronic RA, prior trauma; typically unilateral
316
Frond-like suprapatellar mass with knee joint effusion
lipoma arborescens
317
Causes of hip AVN
Perthes, sickle cell disease, Gaucher's, steroids, intracapsular femur fracture
318
Rim sign (hip MRI)
AVN; high T2 signal line between two low signal lines; implies instability (stage 3)
319
Crescent sign (hip x-ray)
thin subchondral lucency in femoral head; indicates imminent collapse (stage 3)
320
Stages of osteonecrosis (hip)
1 = radiographically occult, edema on MRI; 2 = mixed lytic/sclerotic; 3 = articular collapse; 4 = secondary OA
321
"Rodent facies"
thalassemia; other buzzwords include "hair-on-end" skull and "jail bar" ribs; assoc. with extramedullary hematopoiesis
322
Demographics of Paget's disease
4% at 40 y/o, 8% at 80 y/o; M > F; polyostotic > monostotic
323
Progression of Paget's disease (phases)
lytic => mixed (elevated AlkP) => sclerotic (elevated hydroxyproline); prone to fractures in mixed and sclerotic phases
324
Banana fracture
insufficiency fracture of a bowed long bone; seen in Paget's; femur or tibia
325
Saber shin
bowing of tibia; seen in Paget's
326
Most common complication of Paget disease
deafness; other complications are spinal stenosis, CN palsies, fractures, CHF, secondary hyperparathyroidism, and osteosarcoma
327
Most common bone affected in Paget disease
pelvis; "always" involves iliopectineal line; often fibular sparing in diffuse disease
328
MRI characteristics of Paget's (by phase)
lytic/early mixed (active) = iso T1 with speckles, hetero T2; late mixed = high T1/T2; sclerotic = low T1/T2
329
Best sequence to differentiate active Paget's from malignant transformation
T1 pre-contrast; lose speckled appearance in malignant transformation (foci of high T1 signal fatty marrow)
330
Gorham disease
a.k.a. vanishing bone disease; osteolysis + splenic cysts; skull, shoulder, and pelvis most commonly
331
Eccentric geographic metaphyseal lesion with lobular and sclerotic margins
chondromyxoid fibroma; rarely demonstrates chondroid matrix; may be expansile; T2 bright; typically around knee
332
Paraneoplastic syndromes associated with hemangiopericytoma
hypoglycemia, osteomalacia (oncogenic rickets)
333
Erlenmeyer flask deformity (femur)
Gaucher disease, thalassemia, sickle cell
334
Symmetric DIP erosions with preserved bone density
multicentric reticulohystiocytosis; may also have soft tissue nodules
335
Black urine when exposed to air
alkaptonuria; assoc. with ochonosis (disc space narrowing with calcification at every level)
336
Salt-and-pepper skull
hyperparathyroidism
337
Bullet-shaped vertebral body DDx
achondroplasia, mucopolysaccharidoses, congenital hypothyroidism
338
Posterior vertebral body scalloping
achondroplasia, mucopolysaccharidoses
339
Normal acromio-clavicular and coraco-clavicular distances
AC joint <5 mm, CC joint <11-13 mm; CC ligament has trapezoid (lateral) and conoid (medial) ligaments
340
Post-traumatic fluid collection containing echogenic foci
Morel-Lavallee lesion (degloving); echogenic foci = fat globules, fluid-fluid levels = blood; classically over greater trochanter
341
Anisotropy (definition)
tendons not perpendicular to beam on US appear hypoechoic (injured); normally tendons appear hyperechoic
342
Hip position for arthrogram
internally rotated; aim for superior femoral head-neck junction
343
Shoulder position for arthrogram
externally rotated (supinate hand); aim for inferior-medial humeral head (slightly inside the cortex)
344
Heel pad thickness suggestive of acromegaly
>2.3 cm
345
Calcaneal avulsion fracture at insertion of achilles
specific for diabetes
346
Bony findings in myelofibrosis (XR/CT/MR)
diffuse bony sclerosis (XR/CT); VERY low T1 and low T2 fibrosis in marrow space (MR)
347
Post-radiation marrow changes
edema/necrosis in first 3 weeks (T2 bright) => profoundly fatty marrow (high T1/T2); often with a geographic distribution (beam shape)
348
Bony lesions that irritate adjacent bone DDx
irritation = marrow edema (MR) and/or sclerosis (XR/CT); chondroblastoma, osteoid osteoma, EG, infection
349
Absence of distal femur and proximal tibia
hypothyroidism
350
Normal Insall-Salvati ratio
patella tendon length-to-patella length ratio; patella alta = >1.2; patella baja = <0.8
351
Size criteria for osteoblastoma
>1.5 cm
352
Os trigonum
posterior to talus; assoc. with posterior impingement syndrome of ankle (seen in ballet dancers)
353
How many consecutive slices for discoid meniscus?
depends on slice thickness; 12 mm required (e.g. three 4 mm slices)
354
Little league elbow
avulsion of medial epicondyle, +/- UCL sprain/tear; often with osteochondral injury of capittelum
355
Causes of bone infarcts
sickle cell, alcoholics, radiation, Gaucher, corticosteroid excess, trauma
356
Monostotic or polyostotic - Paget's and fibrous dysplasia
Paget's is more commonly polyostotic; fibrous dysplasia is more commonly monostotic
