MSK Radiology - Crack the Core 1 (reverse order)

DISI stands for? Seen in?

Dorsal Intercalated Segment Instability; see in scaphoid Fx, distal radius Fx (compensatory), radius malunion (adaptive)

#1 carpal Fx?

Scaphoid, most common at waist (70%), risk of AVN to prox fragment. F/B Proximal, Distal, tubercle Fx

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Describe SNAC wrist (scaphoid non-union advanced collapse)

Proximal scaphoid fragment attached to lunate, distal scaphoid fragment into flexion (volar), f/b radioscaphoid arthritis, capitate migration & DISI

Tx of SLAC wrist?

Wrist fusion – more strength, less ROM
Proximal Row Carpectomy: More ROM, less strength

What are the 4 major types of carpal dislocation?

Perilunate, Lunate, Midcarpal, Scapholunate Dissociation (not shown – 3+ mm interval, Terry Thomas)

Which one has the acute (<30) scapholunate angle: DISI or VISI?

VISI (V looks acute), this can be confusing though because carpolunate angle is increased (> 30)

2 eponyms for base of 1st metacarpal Fx? Difference?

Bennett and Rolando Fx. Bennet oblique, Rolando comminuted (T or Y shaped)

In a Bennett Fx, what causes the dorsolateral dislocation?

Abductor pollicis longus

What injury does this illustration show? What ligament is damaged?

Gamekeeper or Skier’s thumb; ulnocollateral ligament injured

In a Gamekeeper’s thumb, what lesion is a/w getting caught with the torn edges of the UCL?

Stener Lesion; the image shows the adductor tendon caught b/w the torn UCL and its insertion site. The displaced ligament won’t heal correctly, needs surgery

Contents of carpal tunnel?

Flexor digitorum superficialis & profundus (x4 each), median n., flexor pollicis longus (major flexors of the digits). Flexor carpi radialis next to it.

Carpal tunnel syndrome is usually from repetitive trauma, but its association with _____ is commonly tested.

Dialysis. Also gigantism/acromegaly, DM

Guyon’s canal syndrome affects what nerve? This nerve is also commonly affected by what fracture (around this area)?

Ulnar nerve (ulnar canal) – can lead to “handle bar palsy.” Fracture of the hook of the hamate can also cause similar Sx

#1 elbow Fx in adults vs. peds?

Adults: radial head
Peds: supracondylar

What are the three eponyms for elbow/forearm Fx (mnemonic)? Describe them.

MUGLER:
Monteggia: ulnar Fx & radial head d/l
Galeazzi: radial shaft Fx, ant ulna d/l at DRUJ,
Essex-Lopresti: radial head Fx, ant d/l ulna at DRUJ (E at hEad)

_____ Tunnel Syndrome occurs at the elbow. Common cause? (pathophys)

Cubital Tunnel Syndrome. Caused by repetitive valgus stress typically or any compressing pathology (tumor, hematoma).

The ulnar nerve passes beneath the cubital tunnel retinaculum at the _________

epicondylo-olecranon ligament or Osborne band

Cubital tunnel syndrome can be caused by this accessory muscle (thus this Dx)

Anconeus –> anconeus epitrochlearis

Ages of ossification centers in pediatric elbow

See picture for CRITOE: 1,3,5,7,9,11

Most common type of shoulder dislocation – what %?

90% anterior inferior. 10% posterior et al
(opposite of hip)

Deformities a/w anteroinferior shoulder dislocation?

Hill Sachs is on Humerus;
Bankart @ glenoid…is on the other Bone?

This Fx also occurs in 10-15% of anterior dislocations in pts over 40

Greater tuberosity avulsion Fx

Common causes of posterior dislocation?

electrocution, seizure

3 signs of posterior dislocation?

Rim sign (wide GH jt), Trough sign (rev. Hill Sachs – impaction @ ant humerus), arm locked in int rotation (note you can see the lesser tuberosity on left image)

third type of dislocation ( other than anterior and posterior)? Eponym?

inferior dislocation, a.k.a. luxatio erecta humeri: arm sticks straight over head

Common injury a/w inferior dislocation?

Axillary nerve injury (60%)

What likely caused this fx?

Bisphosphonates – lateral femoral neck a/w tension (elderly on bisphosphonates); medial is a/w compression (stress fx in runner)

2 major lines to look at in pelvis for anterior & posterior column Fx’s? Which one is a/w anterior vs. posterior?

Iliopectineal: anterior (red)
Ilioischial: posterior (you sit on your ischium – green)

What happens to the hip if you fracture both columns?

completely detached from axial skeleton

What vessels may be injured w/ superior pubic ramus injury?

Obturator & Inf. Epigastric may ride on sup. pubic ramus; particularly w/ lateral approach to hip repair; a/w “corona mortis”

In a hip Fx, the degree of _____ is associated with the risk of (femoral head) AVN?

Degree of Fx displacement

What attaches at these sites (and thus gets avulsed)

Iliac crest: abd muscles
ASIS: Sartorius
AIIS: rectus fomoris
Gr Troch: gluts
Less Troch: ilipsoas
Isch Tub: hamstrings
Pub Symph: ADductors

3 types of snapping hip syndrome? Muscles a/w?

External #1: IT band over greater troch
Internal: Ilipsoas over iliopectineal eminence or femoral head
Intra-articular: labral tears or joint bodies

Which types of femoroacetabular impingement are a/w which gender?

CAM: young men, pistol grip deformity (“femoral head kinda looks like a penis”)
PINCER: middle aged women, cross over sign

What is the crossover sign?

anterior & posterior rims of acetabulum form figure 8 as they cross over in pincer deformity; very unreliable sign (position dependent)

Most common cause of sacral insufficiency fractures?

Osteoporosis; also renal failure, RA, pelvic radiation, mechanical changes after hip arthroplasty, steroids

5 main things (pathologies) to know for the sacrum?

insufficiency fractures, Degenerative changes, U/L SI infection, chordoma, sacral agenesis

Name 1-3 (Fx type and associated injury)

1: Segond, a/w ACL (75%), int rotation
2: Arcuate, a/w PCL (and medial meniscus), ext rot
3: Reverse Segond, a/w PCL (90%)

What’s this sign called and what does it indicate?

Deep intercondylar notch sign (2/2 impaction of lateral femoral condyle), a/w ACL tear

Classic assocation with patellar tendon tear (patella alta)?

SLE, also elderly, trauma, athletes, RA

Bilateral patellar rupture is a/w what primarily?

Chronic steroid use

Tibial plateau Fx – which plateau is more commonly injured? Classification system?

Lateral >> medial. Schatzker classification (2 most common – split & depressed lateral plateau), has limits (e.g. isolated medial plateau, Fx in coronal plane)

General term for this type of Fx? Features seen here? Mechanism of injury?

Pilon Fx (tibial plafond = “ceiling”), due to axial loading. See central impaction (dye punch) @ curved arrow), disrupted syndesmosis, a/w fibular Fx (not seen), talar Fx (double arrow)

#1 most common long bone Fx?

Tibial shaft Fx

What type of Fx is this (classification and eponym)

Tillaux Fx, which is a type of Salter Harris 3

What is this type of Fx? Salter Harris?

Triplane Fx, Salter Harris 4 (but I think different varieties can be different)

Describe different Salter Harris types?

1 through physis, 2 metaphyseal through physis, 3 epiphyseal through physis, 4 through both and physis, 5 is crush injury (3 is like an E for epiphysis)

A Maisonneuve Fx involves the medial tibial malleolus and what else?

Technically the tibiofibular syndesmosis, can be fibular Fx. The Fx does not extend into the hindfoot.

How to calculate Bohler’s angle? What is concerning range?

Line b/w ant. & post. borders of calcaneus on lateral view. If < 20 degrees, concerning for Fx (depressed type I think)

Perilunate dislocation – what injury is associated?

Scaphoid Fx (60%)

Midcarpal Dislocation – what injury/injuries associated?

Triquetrolunate interosseous ligament disruption, Triquetral Fx

Lunate Dislocation – what injury associated?

Dorsal radiolunate ligament injury

4 types of shoulder prostheses and what are the 2 main factors determining which type is used?

TSA, Reverse TSA, Hemi-arthroplasty, Resurfacing.
2 factors: state of rotator cuff and glenoid

When is a reverse shoulder arthroplasty needed? Relies heavily on what muscle?

If the rotator cuff is deficient. If the glenoid is intact, may consider hemiarthroplasty. Reverse SA depends heavily on deltoid.

Options for shoulder arthroplasty if cuff is intact?

Glenoid ok, can use hemi or resurfacing. If not, then need TSA

Most common complication following TSA?

Loosening of the glenoid component (glenosphere & metaglene – like the tripod the glenosphere sits on)

$Posterior acromion fracture 2/2 excessive deltoid tugging.$

Most common complication following reverse shoulder arthroplasty?

Posterior acromion fracture 2/2 excessive deltoid tugging.

If you see bilateral calcaneal Fxs, best next step?

Assess spine for compression/burst Fx (axial loading)

Lateral calcaneal Fx can entrap _______.

Peroneal tendons

3 types of (named) base of the 5th metatarsal Fxs?

Tuberosity Avulsion, Jones, Stress (midshaft). Stress is hard to heal.

Base of 5th: tuberosity avulsion Fx is thought to be 2/2 tug by the __________.

lateral cord of the plantar aponeurosis and/or peroneus brevis (controversial)

What is this sign called and what does it indicate?

Fleck sign, indicating Lisfranc injury (avulsion of the LF ligament @ base of 2nd)

3 (main) types of Lisfranc Fx/dislocation?

Homolateral, Isolated, Divergent

With regard to fractures of the femur and tibia, which side is harder to heal, medial or lateral?

Lateral – a/w tensile forces, constantly being pulled apart, harder to heal.

The most common site of stress Fx in young atheletes?

Tibial stress Fx, most on the compressive (posteromedial) side, at proximal or distal 1/3.

What is the entity seen here at the medial femoral condyle?

Subchondral Insufficiency Fx of the Knee, formerly SONK. Often in little old ladies (osteoporosis), medial side (wt bearing), a/w meniscal injuries. Not actually osteonecrosis.

Stress Fx seen here? Risk of what complication?

Navicular stress Fx, seen in runners, a/w risk for AVN

What is a march fracture?

Metatarsal stress Fx, often in military recruits; look for any periosteal rxn (often radio-occult). Metatarsal Fxs (in general) 5 > 3 > 2 > 1 > 4.

Most common fractured tarsal bone? Usually (intra/extra)-articular? Helpful feature?

Calcaneus. 75% intra-articular. Fx line perpendicular to trabecular lines, can be subtle.

Lower extremity stress Fx’s: name some high risk (hard to heal) vs. low risk (conservative mgmt often succeeds)

High risk (think tension): lateral femoral neck, transverse patellar fx (pulled apart), anterior midshaft tibia (tensile), 5th metatarsal (pulled by tendon?), Talus, Tarsal Navicular (AVN risk), Sesamoid great toe.
Low risk: medial femoral neck, longitudinal patella, posteromedial tibia (compressive), 2nd & 3rd metatarsal, calcaneus

Osteomalacia is usually related to issues with ______. Imaging findings?

Vitamin D: renal causes, liver causes, other causes.
Ill-defined trabeculae, ill-defined corticomedullary jxn, bowing, Looser’s zones (see next Q for image)

So what are Looser’s zones?

Insufficiency Fx technically; wide lucent bands perpendicular to cortex, think osteomalacia or rickets >> OI.

Causes of osteoporosis other than age?

Medications: steroids, heparin, dilantin
Endocrine: Cushings (steroids), hyperthyroid
Anorexia
Osteogenesis Imperfecta

Definition of osteoporosis is related to what score? what’s the other score of interest?

T-score < -2.5 (osteopenia b/w -1 and -2.5) Z-score relative to age-matched control (za zame age)

Examples of conditions which can “trick” the DEXA scan into false positives or false negatives?

Based on density, so….
False positive: absent normal structures, e.g. s/p laminectomy
False negative: osteophytes, dermal calc, metal, compression Fx in area measured, including too much femur when doing a hip

#1 radiographic feature of multiple myeloma?

DIFFUSE osteopenia, more common than punched out lesions

Regional osteopenia, most commonly at hand and shoulder, with preserved joint spaces?

Complex Regional Pain Syndrome, aka Reflex Sympathetic Dystrophy

Bone scan of RSD/CRPS?

Hot on all 3 phases, intra-articular uptake of tracer seen in pts w/ RSD 2/2 increased vascularity of synovial membrane.

Why might the humerus (all fragments) be inferiorly subluxed after a humeral head fracture – consider acute vs. chronic with respect to fracture.

Acute: most likely an effusion.
Chronic: Consider axillary nerve injury, muscular injury (deltoid), possibly (zebra) if Fx was 2/2 fall which was 2/2 stroke.

4 Flexors which do not go through the carpal tunnel?

Flexor hallicus brevis, flexor carpi radialis, flexor carpi ulnaris,

What pts typically get this entity (and what is it)?

Kohler disease (osteochondrosis of tarsal navicular); male pts 4-6 y/o. Not surgical Tx.

$Freiberg Infraction (osteochondrosis of 2nd metatarsal head); adolescent girls - can lead to 2' OA, variable Tx$

What pts typically get this entity (and what is it)?

Freiberg Infraction (osteochondrosis of 2nd metatarsal head); adolescent girls – can lead to 2′ OA, variable Tx

What pts typically get this entity (and what is it)?

Severs disease (osteochondrosis of calcaneal apophysis), common in boys 8-15 y/o

What does the straight arrow point to? What is in compartment 1, clinical significance? What is curving around in 3?

Straight arrow: Lister’s tubercle (of radius)
Compartment 1: APL & EPB; affected by deQuervain’s tenosynovitis
EPL in 3 curves around Lister’s tubercle

Communication of the pisiform recess & radiocarpal joint impies ______.

Normal anatomy; this means you can enter either space for arthrogram and pisiform recess fluid is normal if there is a radiocarpal effusion.

Communication of the glenohumeral jt and subacromial bursa implies ______

Full thickness rotator cuff tear

Communication of the ankle jt and common (lateral) peroneal tendon sheath implies ______

Tear of the calcaneofibular ligament

Communication of the Achilles tendon and posterior subtalar joint implies ______

***pathology; Achilles tendon does not have a true tendon sheath. (have to investigate more)

Name the structures

1: TFC
2: Dorsal RU ligament
3: Volar RU ligament
4. Ulnotriquetral ligament
5: Ulnocarpal ligament
6: Lunotriquetral ligament

2 types of TFC injury

Acute (traumatic)
Chronic (mostly ulnar abutment syndrome)
Pic shows contrast going from radiocarpal jt through tear (black arrow) into RU jt.

What are the 2 components of ulnar abutment syndrome?

positive ulnar variance w/ cystic change @ the lunate

How common is degeneration of the TFC?

Common; appx 50% @ 60 y/o

What is the finding at the arrow? What is the other associated finding seen here? Who gets this (demographic)

Kienbocks (AVN of lunate); associated w/ NEGATIVE ULNAR VARIANCE. Pts in 20s-40s get Kienbocks

What is the condition seen here? Who gets it?

DeQuervain’s Tenosynovitis (new mom holding baby), @ 1st dorsal (extensor) compartment (EPL & APL)

The presence of a _______ is a prognostic factor in Dequervain’s tenosynovitis (anatomic factor)

Intracompartmental Septum

Who tends to get a syndrome involving where these tendons intersect?

Rowers tend to get intersection syndrome ( extensor carpi radialis brevis & longus tenosynovitis); note that pain is typically more medial/ulnar than Dequervain’s

Tenosynovitis of nontuberculous Mycobacterial infection tends to affect what most?

Hand & wrist; diffuse exuberant tenosynovitis (fluid around tendon), sparing muscle

Tenosynovitis of multiple flexor tendons or extensor carpi ulnaris suggests this entity

RA – may occur before bone findings!

Tenosynovitis isolated to the 6th compartment indicates…

RA (extensor carpi ulnaris)

Infectious tenosynovitis of flexor tendon – urgency?

Emergency (surgical); can get increased pressure & necrosis of tendon, poor outcome

What is this and who gets it?

Duputren’s contracture; white person from northern Europe w/ alcoholic liver dz is classic (nodular mass @ palmar aspect of aponeurosis, usually ring or pinky finger

Big 3 finger tumors. T1 findings for these?

Glomus, Giant cell tumor of tendon sheath (tendon PVNS), Fibroma. All 3 are dark on T1

Of the big 3 finger tumors, this one enhances avidly and is T2 bright

glomus tumor; giant cell tumor of tendon sheath has variable enhancement

Of the big 3 tumors, which blooms/does not bloom on GRE? Other helpful feature for GCTTS?

Blooms: Giant cell tumor of tendon
Does not bloom: fibroma
Morphology may be most helpful for GCTT though as in pic (lobulated, septa if not obvious)

What do the 3 arrows point to?

Yellow: Median N.
Blue: Radial N. (divides into sup & deep)
Red: Ulnar N.

Sign seen here? Indicates what?

T sign, indicates partial UCL tear (contrast material extending medial to tubercle)

Osteochondritis Dissecans tends to affect the _____ of the elbow, while Panner disease tends to affect the _____ (anatomy). Loose bodies in each? Other feature/s helpful to distinguish?

They BOTH affect the capitellum (OCD favors the capitellum).
Age: Panners 5-10, OCD teenager
Loose bodies in OCD, not Panner.
MRI: both dark T1, bright T2

Which is more common – medial or lateral epicondylitis?

Lateral Epicondylitis (“Tennis players” although 95% pts are not tennis players)

Name stuff

1: Common extensor (lat epi)
2: LCL/LUCL
3: Annular ligament (wraps around radial head)
4: Biceps tendon (radial tub)
5: common flexor tnd
6: UCL (med epi, down sublime tubercle which is medial coronoid)
7: Brachialis tendon (@ coronoid)

Name 1-3, which are torn? Which is most important?

Ulnar Collateral Lig (MCL)
1: Anterior band (most important)
2: Posterior band
3: transverse band (intact)

What is the entity seen here? What is actually injured in these cases (can be 2 structures)

Extensor tendon injury: extensor carpi radialis brevis and/or LCL complex tear (varus stress)

Lateral epicondylitis – not really “itis” but rather what pathological process

Angiofibroblastic hyperplasia, repetitive microtears & fibrous repair, granulation tissue & neovasc, calcification, necrosis

If that’s a lymph node, what dz does this pt have?

Epitrochlear LAD seen in cat scratch dz; also hypodense or hypoechoic splenic lesions btw

Dialysis pts can get constant pressure on elbow, leading to this condition:

Dialysis elbow, result of olecranon bursitis

Two types of impingement – which is impinged by surrounding structures? What types?

External Impingement:
1. Hooked acromion (type III Bigliani) more w/ external (pic)
2. Subacromial osteophyte or coracoacromial ligament thickening
3. Subcoracoid impingement

Which types of external impingement are seen here?

On right, the supraspinatus tendon is seen as it travels under the coracoacromial ligament.
On the left, the greater tuberosity is in contact with the acromion

Which tendon is involved in subcoracoid impingement? Hint: attaches to lesser tuberosity

Subscapularis

Pts with general joint laxity, may get this condition in both shoulders

Multidirectional Glenohumeral Instability

Which type of impingement damages the infraspinatus?

Posterior superior internal impingement (esp in athletes who make overhead movements: greater tuberosity & poserior inferior labrum do the pinching)

A surgeon cares about a rotator cuff tear > ___%

50%

What does a massive rotator cuff tear actually mean?

2/4 rotator cuff muscles torn

How do you know if there is a full thickness rotator cuff tear?

Gad in the bursa on T1; high T2w signal at the expected tendon location

Enchondroma classically has nice arcs and whorls of chondroid matrix, this is true everywhere except ____ where it has this appearance.

Fingers & toes – cystic (most common cystic lesion @ hands & feet – high yield!); no periostitis (benign cartilage cyst basically)

Does fibrous dysplasia have periostitis?

NO – essentially it’s just a focus of scar tissue

2 hereditary conditions a/w polyostotic fibrous dysplasia? Differentiating factors?

McCune Albright: a/w young girl, cafe au lait spots, precocious puberty/other endocrine conditions
Mazabraud Syndrome: Middle aged woman #1, a/w soft tissue myxomas, increased risk of malignant transformation

#1 differentiating factor of enchondroma vs. low grade chondrosarcoma?

PAIN

2 syndromes a/w enchondromas?

Ollier’s: *O*nly enchondromas
Maffuci’s: *M*ore than enchondromas, also hemagiomas (phleboliths), *M*alignant potential (20% progress to chondrosarcoma, other CA – GI, ovary)

Fibrous dysplasia @ the proximal femur produces this abnormality

Shepherd’s crook deformity

Mixed lytic & sclerotic lesion that resembles fibrous dysplasia in the tibia with malignant potential, rare

Adamantinoma

This lesion is included in essentially every differential for pts < 30 y/o with a bone lesion.

Eosinophilic Granuloma, can be solitary or multiple, lytic or blastic, with or w/o sclerotic border, w/ or w/o periostial rxn. Can even have osseous sequestrum.

Given that nearly anything can be EG, what 3 classic appearances are often presented?

Vertebra plana in a kid
Skull with lucent beveled edge in a kid
Floating tooth with lytic lesion @ alveolar ridge

DDx for osseous sequestrum

Osteomyelitis, Lymphoma, Fibrosarcoma, EG, Osteoid osteoma can sometimes mimic appearance

“4 horsemen” (most common lesions) of the epiphysis/apophysis

AIG Company: ABC, Infection, Giant cell tumor, Chondroblastoma (clear cell)

Name some epiphyseal equivalents

Big ones: carpals, patella, calcaneus, greater & lesser trochanter, tuberosities…

5% of giant cell tumors will have _____ mets

Pulmonary

GC tumors: most commonly found at ______, age ____, associated with this other lesion.

Most common @ knee, abutting articular surface; 20-30 y/o with CLOSED PHYSIS, a/w ABC (can turn into them). Fluid levels on MR (like ABCs, or also telangiectatic osteosarc)

Waste basket term if you don’t want to remember size criteria for non-ossifying fibroma?

Fibroxanthoma

Weird zebra syndrome with non-ossifying fibromas (fibroxanthomas)?

Jaffe Campanacci Syndrome: multiple NOFs, cafe au lait spots, mental retardation, hopogonadism, cardiac malformations

This lesion: pain at night, relieved by aspirin. MR appearance?

Osteoid osteoma. MR: large amount of edema compared to lesion size

Osteoid osteoma: 2 (general) preferred locations

1. meta/diaphysis of long bones
2. posterior elements of the spin

Osteoid osteoma in the spine is a/w this other finding

Painful scoliosis which points away from the lesion. Can Tx with RFA (if not too close to nerves)

3 other associations of osteoid osteoma (can see on imaging)

Increased length & girth of long bones
Synovitis (if intra-articular, leads to early OA)
Arthritis: from synovitis or 2/2 altered jt mechanics

Essentially an osteoid osteoma > 2 cm

Osteoblastoma; pts < 30, often in long pones & posterior elements

3 classic blastic mets

Prostate, carcinoid, medulloblastoma

2 classic lytic mets (i.e. not myeloma)

Renal, Thyroid

Classic finding of multiple myeloma in the spine?

Complete vertebral body destruction with sparing of the posterior elements.

Order of sensitivity for myeloma: bone scan, MR, myeloma survey (XR)

MR > myeloma survey > bone scan

Mechanism of myeloma leading to lytic lesions? This produces this finding btw, which is more common than a focal lytic lesion…

Plasma cell proliferation increases surrounding osteolytic activity; diffuse osteopenia more common than focal lytic lesions

Benign lesions with NO pain or periostitis

Never Ever Feel Something:
NOF, EG, Fibrous Dysplasia, Solitary Bone Cyst

Multiple benign lesions differential

Find More Empty Eggs (lytic stuff) Here
Fibrous Dysplasia, Mets/Myeloma, EG, Enchondroma, HyperPTH

Which lesion points away from the joint: osteochondroma or supracondylar (avian) spur

Osteochondroma points Oway from the joint (or something)

Looks like an NOF in the anterior tibia w/ anterior bowing…

Osteofibrous Dysplasia (cannot differentiate from adamintinoma on imaging) – seen only @ tibia or fibula of young child (usually < 10 y/o)

(8) DDx for tibial bowing

NF1, foot deformities, physiological, hypophosphatasia, rickets, Blount dz, OI, Dwarvism…

What’s this aunt Minnie (hint)

Mouse ear deformity: psoriatic arthritis (along w/ periosteal bone formation, pencil in cup, IP joint preference, sausage digit, ivory phalanx, acral osteolysis…)

MSK Radiology - Crack the Core 1 (reverse order)

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