Core Radiology MSK Flashcards
H shaped vertebra are due to AVN of the endplates which is present in both Gaucher’s and Sickle cell. How can you differentiate?
Gaucher = hepatosplenomegaly
Sickle cell = Autosplenectomy
Gaucher = Erlenmeyer flask deformity (metaphyseal flaring)
Diffuse sclerosis of the bones with rugger jersey spine, what’s the diagnosis?
Osteopetrosis
What’s hereditary hyperphosphasia and how is the radiological features different from Paget’s disease?
Child Paget’s with trabecular and cortical thickening, bowing of the legs and osteopenia
HOWEVER there is epiphyseal sparing
Another name for lincon log vertebra?
H shaped vertebra
Case with marrow expansion, what’s your top differential?
How does marrow expansion look like in the
Hand
Skull
Facial bones
Long bones
Thalassemia
Hand: widening and squaring of the phalanx and metacarpals
Skull: hair on end
Facial bones: Obliteration of the sinuses > rodent face
Long bone: Erlenmeyer flask deformity (metaphyseal flaring)
What does myelofibrosis look like?
Demo: Old patient
Radiograph: diffusely sclerotic bones
Other findings: anemia and splenomegaly
What are the types of stress fractures?
Fatigue and Insufficiency
Insufficiency = bone is insufficient but stress is normal (bone abnormal, stress normal)
Fatigue = bone is fatigued from repetitive stress however bone is normal (bone normal, stress abnormal)
What is a pathological fracture?
Normal stress on bone weakened by underlying lesion/Pagets/Infection
Which sequence is best used to avoid magic angle phenomenon when visualizing the patellar tendon?
T2
What is the MRI presentation of tenosynovitis and what is a common pitfall?
Fluid tracking around the tendon circumferentially
Pitfall; biceps tendon with fluid tracking.
What are the causes of tenosynovitis?
Repetitive motion or surrounding inflammation (infection/inflammatory arthritis)
What is the MRI presentation of tendinosis and what is it’s other name?
Tendinosis = Myxoid degeneration
MRI: Intermediate intrasubstance signal, with normal or enlarged tendon.
NOTE: if fluid signal is seen then it’s NOT tendinosis, it’s a partial tear.
MRI presentation of partial tear vs complete tendon tear?
Both fluid signal
Partial: thinning/thickening of the tendon but incomplete disruption of the fibers.
Complete tear: retraction of the tendon
What is Jones fracture?
Fracture of the metaphyseal-diaphyseal 5th metatarsal.
What’s Friberg infarction and what is the age demographic?
Demo: young women in heels
Avascular necrosis of the second metatarsal
What’s the tendon involved in sesamoid fracture?
Flexor hallucis brevis
What does the Lisfranc ligament connect?
Medial cuniform to the second metatarsal base
Other name of navicular necrosis and what’s the demographic?
Child boy = Kohler
Adult female = Weiss
What’s the lover’s fracture? And what do you recommend if seen?
Calcaneal fracture due to high impact trauma
Associated with lumbar spine fracture, aortic/renal injury so we recommend lumbar and abdominal imaging.
What’s important to comment on after diagnosing a calcaneal fracture?
Subtalar extension because this allows us to use the Essex-Lopresti classification
What’s the most important talus fracture and why?
Talar neck fracture as it predisposes to osteonecrosis
What is this sign and why is it important?
Hawkin sign; subchondral lucent band visualized 6-8 weeks after tarsal bone fracture which indicates blood supply to the dome and no avascular necrosis (good prognosis)
What is this sign and what does it indicate?
C sign
Osseous talocalcaneal coalition
Talar beak sign (in all coalition)
What is this sign and what does it indicate?
Anteater sign
Osseous calcaneonavicular coalition
Talar beak sign (in all coalition)
What are the types of tarsal coalition and where are they located?
What is helpful sign?
Osseous, cartilagenous, ligamentous
Located:
Talocalceneal
Calcaneonavicular
What are the lateral ankle ligaments and which is most commonly injured?
1- Anterior talofibular (most common)
2- Posterior talofibular
3- Calcaneofibular (2nd most common)
Which muscle connects to the base of the 5th metatarsal?
Peroneus brevis
Where does peroneus longus attach?
Curves under the foot and attaches to the medial cuniform
What makes up the medial ankle ligaments?
Deltoid complex and spring ligament complex
What is the deltoid complex compromised of?
1- anterior tibiotalar
2- posterior tibiotalar
3- tibiocalcaneal
4- tibionavicular
Contents of the tarsal tunnel anterior to posterior
Tom, Dick and Harry
Posterior Tibial tendon
Flexor Digitorum longus tendon
Flexor Hallucis longus tendon
Posterior tibial artery and nerve
Danis-Weber classification
(Depends on the level of fibular fracture and resultant syndesmotic injury. )
Weber A; distal fibular fracture with intact syndesmosis
Weber B; more proximal trnassyndesmotic fracture
Weber C; high fibular fracture above the level of the syndesmosis however associated with total syndesmotic rupture and ankle mortise instability.
If you see a medial malleolar fracture or widening of the ankle mortise what’s the next step?
Take a radiograph of the proximal fibula for associated Maisonneuve fracture
What is this fracture called?
Pilon fracture; comminuted vertically oriented fracture of the distal tibia likely due to axial loading.
What is the special name for this fracture and what does it involve?
Triplane fracture:
Vertical epiphyseal fracture
Horizontal physis fracture
Oblique metaphyseal fracture
What’s the special name of this fracture and what does it involve?
Tillaux fracture:
Salter Harris 3 of the lateral tibial epiphysis in adolescents
How do you suspect achilles tendon injury on plain radiograph?
Increase soft tissue in the Kagar fat pad
Notching of the soft tissue
What’s the differential diagnosis of achilles tendon injury on radiograph?
Accessory soleus muscle; soft tissue mass in Kager fat pad
Haglund disease (retrocalcaneal bursitis)
What is recommended in all knee dislocations and why?
What’s the most common knee dislocation
Anterior is most common.
CT angiography is recommended for all knee dislocations because even if the distal pulses are intact there is a high risk of popliteal artery injury.
What is the finding?
dorsal defect of patella usually located in the superiolateral aspect
Which fractures are more stable, medial or lateral?
Lateral tibial plateau fractures are more stable than medial.
Lateral = lemme goooo
If there is injury to the meniscal root what do you look for and what can it mimic?
Look for meniscal extrusion
but don’t confuse it for the meniscofemoral ligament
What is the red zone of the meniscus?
Peripheral third of the meniscus is relatively vascular called the red zone in which injuries may heal spontaneously
How do you differentiate meniscus degeneration from tear?
Degeneration; high signal but not fluid signal and does not extend into the articular surface.
Tear; fluid signal that extends into the articular surface
Where are horizontal tears usually located and how does this make sense?
Posterior horn of the medial meniscus likely due to degenerative changes and less likely due to trauma.
Note: Osteoarthritis is asymmetrical with predominant involvement of the medial compartment
What is a vertical or longitudinal tear?
Tear the follows the curve of the meniscus
What is the most sensitive finding for detecting a bucket handle tear?
Absent bow tie sign
What are the signs seen in bucket handle tear?
Double delta; fragment displaced anteriorly
Double PCL; fragment displaced centrally into the intercondylar notch (most common) this only applies to the medial meniscus
What is this sign?
Double delta sign which indicates anterior displacement of the bucket handle tear fragment.
Radial tear/transverse tear
Extends from the free edge of the meniscus to the periphery occurring through the body
What is the sign of radial tear and what is this tear associated with?
Ghost meniscus occurring through the horn usually adjacent to the intercondylar notch.
Associated with meniscal extrusion
What is a meniscal cyst and why is it important to be mentioned?
Extension of joint fluid through meniscal tear
Importance: Can cause symptoms even after meniscus is resected and sometimes cannot be seen arthroscopically.
Define a discoid meniscus and how is it detected on MR?
Meniscus extending to the central tibial plateau
Exact measurement: meniscus body measurement more than 1.5 cm
MR: Bow tie appearance 3 slices or more (4mm thick)
Which meniscus is commonly involved in discoid meniscus and what is the presenting history?
Lateral meniscus
Hx: Locking/clicking of the knee in an adolescent.
Anterior cruciate ligament attachment and insertion
Arises: femoral intercondylar notch Attaches: anterior tibial plateau lateral to the tibial spine
Which attachment is stronger within the ACL and what is the clinical significance?
Tibial attachment is stronger causing more tears from the femoral end.
ACL tear on MRI
frank discontinuity of ligament fibers or abnormal course and signal
ACL tears are associated with two entities, name them.
Medial meniscal and MCL tears ( O’Donoghue’s triad aka unhappy triad)
Segond fracture; avlusion fracture of the lateral plateau.
What are the secondary findings in ACL tears?
Contusion pattern: lateral femoral condyle and posterolateral tibial plateau
Buckling of the PCL
What is Segond fracture associated with and what’s the next step?
1- ACL tear
2- Iliotibial band syndrome
Next step MRI because of the previous assocations.
The iliotibial band inserts at
Gerdy tubercle of the tibia
Posterior cruciate ligament arises and inserts
Arises: femoral intercondylar notch
Inserts: posterior tibial plateau.
PCL tear appearance on MRI
Increased laxity of the PCL with or without abnormal high signal intensity
Medial collateral ligament arises and attaches to
Why is it not visualized by arthroscopy?
Arises: Posterior aspect of the medical femoral condyle
Attaches: Medial tibial metaphysics
Not visualized by arthroscopy because it’s extrasynovial
Grades of MCL tear
Grade 1; Sprain; high signal of the soft tissue with normal signal ligament
Grade 2; severe sprain/partial tear; high signal/ partial disruption of the MCL fibers.
Grade 3; Complete disruption of the MCL
The lateral collateral ligament is compromised of many structures, 3 of which are visualized by MRI. Name them.
anterior to posterior;
1- Biceps femoris
2- LCL
3- Iliotibial band
The biceps and LCL attach on the lateral fibular head. The iliotibial band attaches to the Gerdys tubercle.
Clinically: anterolateral knee pain in a runner. DDx
IT band syndrome; fluid surrounding the iliotibial band
Lateral meniscus tear
The quadriceps originate from ________ except _________ it originates from _________
Femur
except: rectus femoris
from : AIIS
Define patella alta and patella baja
Alta; abnormally high patella, > 1.2
Baja; abnormally low patella, < 0.8
What is Jumper’s knee?
Patellar tendinosis = Jumper’s knee = thickening of the patellar tendon
History of loss of knee extension, what’s your differential diagnosis and how do you distinguish between the two?
Quadriceps tendon tear = Patella baja
Patellar tendon injury = Patella alta
What are the findings and diagnosis?
Bone marrow contusions; lateral femoral condyle and medial patellar facet with tearing of the medial retinaculum
Diagnosis: Patellar dislocation relocation
Define Osgood-Schlatter disease and the MRI findings.
Osteochondrosis of the tibial tubercle due to repetitive microtrauma in adolescent.
MRI:
1- increase signal of distal patellar tendon
2- marrow edema in the tibial tubercle
3- edema within Hoffa’s pad
What are the types of cartilage injury?
surface irregularity, fissuring, delamination
What’s the distribution of Osteochondrosis Dissecans
1- knee (lateral medial condyle)
2- ankle(posteriomedial or anteriorlateral talar dome)
3- elbow
What’s an unstable fragment in osteochondrosis dissecans and what is the complication?
Unstable fragment, lesion not attached to bone causing secondary osteoarthritis.
MRI finding of unstable osteochonrosis dissecans
Curvilinear high signal intensity on fluid sensitive sequence interposed between the fragment and underlying bone.
If pigmented villonodular synovitis is seen outside the knee joint it is termed
Giant cell tumor of tendon sheath
Whats the most common site for pigmented villonodular synovitis, the radiographic and MRI findings
Knee
Radiograph; knee effusion, soft tissue mass posterior to knee
MRI; hemosidernin deposit; dark signal on T1 and T2, with blooming on gradient echo sequences.
Describe the findings and diagnosis.
Overgrowth of intracapsular synovial fatty tissue, causing lobulated and globular intra-articular fatty masses.
Lipoma arborescens
Where is a Baker cyst located and what is an alternative diagnosis.
Located between the semimembranosus tendon and medial head of the gastrocnemius muscle. (Baker’s M&M)
DDx popliteal aneurysm.
Tennis leg
Tear of the plantaris tendon or medial head of the gastrocnemius
The center of the acetabulum that is not covered by cartilage is called
Pulvinar
Findings and diagnosis
PD; FAT SAT
Structure mostly the plantaris tendon. Note the abnormal signal within the medial head of gastrocnemius
Dx: Ruptured plantaris - tennis leg
Which muscles attach to the greater trochanter?
Gluteus medius, minimus
Obturator internus and externus Piriformis
Which muscle attaches to Lesser trochanter?
Note: Fracture in the lesser trochanter is always pathological until proven otherwise.
Ilipsoas
What is an easy way to establish whether or not there is a fracture to the anterior or posterior column of the acetabulum?
Iliopectinal and ilioischial lines disruption
Which acetabular column is commonly fractured?
Posterior
Name the intracapsular and extracapsular femoral fractures and why is it important
Femoral head and neck fractures = intracapsular, complications include femoral head osteonecrosis
Intertrochanteric and subtrochanteric = extracapsular, direct injury, rarely cause osteonecrosis.
Types of femoral neck fracture
Subcapital (most common)
Transcervical
Basicervical
Technical factors to adjust when patient with metallic prosthesis undergoes MRI
1- Decreasing the field strength
2- Fast spin echo sequences instead of gre
3- Increasing the receiver bandwidth, which will increase the noise, so we need to increase the number of acquisitions.
4- Artifacts can be directed in the superior-inferiro plane so the region
5- Decrease voxel size by decreasing slice thickness and increasing matrix size.
Indications of hip MRI
Occult traumatic fracture since radiographs are insensitive for detection of nondisplaced femoral neck fracture.
Occult stress fracture
Stress fractures; either fatigue or insufficiency fractures
Radiographs insensitive for detection of hip stress fractures, if present looks like a band sclerosis.
Classic location for femoral stress fractures
Inferomedial femoral neck
Less commonly superior femoral head fractures can mimic avascular necrosis, how to differentiate on MRI
AVN smooth and concave to articular surface, insufficiency fracture irregular low intensity fracture line convex to the articular surface.
If there is a stress fracture in an atypical location, what can be a clue during history taking
Bisphosphanate use
Arterial supply to the femoral neck
Medial femoral circumflex artery
Non traumatic causes of AVN
1- Red cell abnormalities
2- Abnormality of marrow packing (Gaucher)
secondary effects of meds (steroids)
alcohol
immunosuppression which tend to be bilateral.
Diving (Cassion’s disease)
Most common site for AVN?
Proximal femur and proximal humerus
Ficat staging for AVN
Stage 1; normal radiograph with signs of AVN on MRI
Stage 2; cystic and sclerotic changes
Stage 3; loss of normal spherical shape due to collapse of the subchondral bone. Subchondral lucent line = cresent sign.
Stage 4; Flattening of the femoral head and secondary osteoarthritis. Tx joint replacement.
What is this sign?
Subchondral lucent line = cresent sign which indicates avascular necrosis. Unlike Hawkin’s sign in the talar dome, it’s a lucent line within the talar dome if present decreases the likelihood of developing AVN.
Describe the findings
and what is it pathognomonic for?
Geographic subchondral lesion outlined by a serpentine low signal rim on T1 and on T2, two intensities are seen
Double line sign
Diagnosis: AVN
Transient bone marrow edema/ transient osteoporosis of the hip
MRI finding and demographic
Note: It’s a diganosis of exclusion
Demo: severe hip pain, young, middle aged adult, men, pregnancy
MRI: T1, diffuse low signal, high signal on T2 with signal extending from the femoral head into the neck.
Hip labral injury
Most common cause
Predisposing factor
Best diagnostic study
Most common location
MCC: chronic repetitive trauma rather than acute
Predisposing factor: Femoracetbaular morphological changes i.e DDH and femoral acetabular impingement
Best diagnostic study: MRI arthrogram
Most common location: anteriosuperior
Femoroacetabular impingement types
How do we make the diagnosis?
Cam
Pincer- type
Mixed
You need clinical symptoms for diagnosis (controversial topic)
Cam impingement
Causes
Demographic
Treatment
Many causes examples
1- Legg-calve-perth
2- DDH, slipped capital femoral epiphysis
Demo; young athletic males
Treatment: osteoplasty
Name the deformity and diagnosis
Pistol grip deformity
Dx: Cam impingement
Chance fracture/ Seat belt fracture definition
Flexion distraction injury, horizonal splitting of the vertebra beginning posteriorly in the spinous process/lamina
What are the measurements for craniocervical dissociation and ligamentous laxity
More than 12 mm BD interval; craniocervical dissociation
More than 2.5 mm AD interval adults and more than 5 in pediatrics ; ligamentous laxity
Define a Jefferson’s fracture
Which view on xray is helpful and what can you appreciate?
symmetrical fractures of the anterior and posterior arches of c1
Due to axial loading to the vertex
Open mouth- odontoid view = lateral masses are displaced laterally.
What are the 3 types of odontoid injury?
How does this fracture come about?
1 = tip of the dens
2= base of the dens (unstable)
3 = base of the dens extending into the vertebral body (stable/unstable)
Flexion injury
Hangman’s fracture definition
What’s characteristic on lateral radiograph?
Hyperextension causing traumatic spondylolysis of C2 = bilateral fractures through the pedicles of C2
Characteristic radiograph finding: disruption of the spinolaminar line.
Burst fracture
Compression fracture w/ retropulsion
Flexion teardrop
Avulsed bony fragment from anterior inferior aspect (anterior longitudinal ligament avulsion) with posterior displacement of the vertebrae into the spinal cord
What’s the most severe cervical spine injury and why
flexion tear drop due to it’s complication;
Anterior cord syndrome = complete paralysis and loss of pain and temp, dorsal column is intact
Extension teardrop fracture
It’s a stable fracture
usually at C2-C3 with an
anterior inferior avulsion fragment
No subluxation
Spinolaminar line not affected.
Clay Shoveler’s fracture
Displaced avulsion fracture of the spinous process
Lower cervical spine
Bilateral interfacetal dislocation (locked facet)
- Hyperflexion injury
- Complete disruption of all spinal ligaments
- Anterior dislocation of the affected vertebrae
Sign: naked facet sign (axial)
Perched facet: less severe variation (subluxation but not displacement)
Is a unilateral facet dislocation stable or unstable?
stable
Grisel syndrome
Non-traumatic rotatory subluxation C1-c2 caused by inflammatory mass i.e pharyngitis or retropharyngeal abscess.
Most common glenohumeral dislocation
Best seen on
Anterior GH dislocation where it’s displaced anterior inferiorly.
Best seen on axillary view
Define Hill sachs and Bankart
Hill sachs = compression fracture of posterolateral aspect of humeral head
Bankart = injury to the anterior-inferior rim of glenoid usually cartilaginous
What are the two signs seen in posterior shoulder dislocation
Light bulb sign = fixed internal rotation
Trough sign = compression fracture of the antero- medial humral head (reverse hill sach)
What happens in inferior shoulder dislocation?
- Rotator cuff injury
- Greater tuberosity fracture
- Injury to the axillary n + a
The subacromial and subdeltoid bursae normally communicate with each other and not the with the glenohumeral joint. IF you inject contrast into the glenohumeral joint and it extends into the subacromial/subdeltoid bursae, what does that indicate?
Complete tear
Type 3 and 4 acromion and clinical significance
Type 3; hooked undersurface
Type 4; convex undersurface
Significance; lead to rotator cuff tears
Os acromial
Persistent accessory ossification center of the acromion in patinets above 25 y
MRI findings with edema in this area suggests that it’s the cause of the patient’s shoulder pain.
Rotator cuff tendon insertion
Greater tuberosity; supraspinatus, infraspinatus, teres minor
Lesser tuberosity; subscapularis
Tendinosis/Tendiopathy
MRI finding and differential diagnosis
(Mxyoid degeneration of tendon)
MRI: diffuse/focal thickening with intermediate signal intensity on T1/T2
DDx: Magic angle artifact, may stimulate tendinosis/ partial tear, look for the T2
What is the footprint of the shoulder?
Site of attachment of tendons at the greater tuberosity
Most commonly injured rotator cuff tendons from most to least
Most commonly injured; supraspinatus, next infrapspinatus, least affected teres minor
Partial thickness tear MRI finding
MRI: abnormal signal intensity of the muscle/tendon but not extending through it’s entire thickness AND fluid signal.
Types of partial tear in the rotator cuff tendons? and what’s the most common type
Division; bursal-surface, articular surface, or intrasubstance
MC type: articular
40 % of supraspinatus tears are associated with
infraspinatus tears
Note: Infraspinatus is rarely torn in isolation
Chronic full-thickness rotator cuff tear due to RA has a classical appearance
Humeral head migrates superiorly and may articulate with acromion
Fatty degeneration of the muscle usually occurs within _____ weeks of injury of the tendon
4 weeks!!!
Adhesive capsulitis/ Frozen shoulder
Thickening and contraction of the glenohumeral joint capsule.
Clinical diagnosis however MRI; thickening of the joint capsule and synovium > 4mm assessed at the level of the axillary pouch.
Where do the glenohumeral ligaments attach?
Superior and middle = lesser tuberosity to the supraglenoid tubercle of the scapula
Inferior = inferior glenoid labrum to the anatomic neck of the humerus
What is the rotator interval is a triangular region
Where is it located and what is it’s purpose?
Purpose: allows rotational motion around the coracoid process
Located between the supraspinatus and subscapularis tendons
What does the rotator interval contain?
- Coracohumeral ligament (CHL)
- Long head of the biceps tendon (LHBT)
- Superior glenohumeral ligament (SGHL)
Where do the glenohumeral ligaments arise from
Labrum
Most important component of the capsulolabral complex for maintaining stability in abduction and external rotation
Inferior glenohumeral ligament (IGHL)
Where does the biceps tendon attach?
Anterosuperior glenoid rim along with the SGHL and MGHL
The biceps tendon sheath connects with ______ and it’s importance is
The sheath communicates with the glenohumeral joint and thus fluid in the tendon sheath may be normal.
The biceps pulley is formed by
- Superior glenohumeral ligament
- Coracohumeral ligament
- Distal fibers of the subscapularis tendon.
Bicep tendon tears are associated with
Supraspinatus tear
oR
Risk of impingement by the supraspinatus
Biceps tendon subluxation vs dislocation
subluxation = still contact with the groove
dislocation = no contact with the groove
Biceps subluxation is associated with ______________
Biceps dislocation is associated with ______________
Subluxation = transverse ligament ear
Dislocation = subscapularis tendon injury
Most shoulder instability lesions occur at this location __________________ and are associated with
Anterior-inferior aspect of the glenohumeral joint and associated with anterior band of the ligament.
Define bankart lesion and it’s differential
Injury to the anteroinferior labrum due to anterior glenohumeral dislocation with stripping of the scapular periosteum
Labrum might migrate superiorly and appear as balled up mass-like object producing glenoid labrum ovoid mass (GLOM sign).
DDx dislocated biceps tendon, air bubble (MR arthrogram was performed)
What is an osseous bankart and it’s complications?
Fracture of the anterior-inferior glenoid rim
Complication; predisposition to recurrent dislocation due to glenoid insufficiency
Define Hill-Sach fracture and how to detect it on MRI
Impaction fracture of the posterolateral humeral head caused by anterior dislocation
5mm slices, normal humeral head should appear round in the 3 consecutive slices
Subtle hill sach; bone marrow edema without of fracture superiorly.
What is anterior labro-ligamentous periosteal sleeve avulsion (ALPSA)
Variant of Bankart
Variant of Bankart
Also representing anterior-inferior labral injury.
How to differentiate? Scapular periosteum is intact
What is Perthes lesion and how is it visualized?
Avulsion of the anterior-inferior labrum
Labrum remains attached to scapular periosteum
Very difficult to visualize
MR arthrography with ABER is often necessary for diagnosis
What makes the borders of the quadrilateral space and what is it’s significance?
posterior aspect of axilla, humerus laterally, long head triceps medullary, teres minro superior, and teres major inferiorly.
Significance: axillary nerve and posterior humeral circumflex artery
What is seen in axillary nerve injury
Axilary nerve supplies both the deltoid and the teres minor, however if there is injury only the teres minor will atrophy
Define a paralabral cyst.
Where is it seen?
What is it’s complication?
Very specific finding for labral tear even when labral signal is not altered. Usually seen in soft tissue adjacent to the labrum but may extend into the bone.
May cause nerve entrapment.
Suprascapular nerve entrapment
Location:
Nerve supply:
Caused by
Location: Suprascapular notch
Proximal Innervation; supra and infraspinatus.
Caused by: paralabral cyst
Elbow dislocation is
1. Associated with
2. Most common type
3. Next step
Ulnar fractures
Most common: Posterior dislocation of the radius and ulna with respect to the humerus
Next step: Obtain full forearm radiographs because the fracture can be distal.
What is the sail sign and what is considered more specific?
Sail sign; elevation of anterior fat pad only and less specific
Elevation of the posterior fat pad is nearly diagnostic
Most common elbow fracture in pediatrics and adults
Pediatrics: Supracondylar fracture
Adults: Radial head fracture
If fat pad sign is seen and no fractures what’s the next step?
Recommend additional views or CT scan
Essex- Lopresti fracture-dislocation
Radial head fracture and tearing of the interosseous membrane with ulnar dislocation at the distal radioulnar joint.
Monteggia fracture -dislocation
Ulnar fracture and radial dislocation at the elbow
Galeazzi fracture-dislocation
Fracture of distal third of radius with ulnar dislocation at the distal radioulnar joint.
Colles fracture
Distal radius frature with dorsal angulation
Usually intra-articular
FOOSH
Hutchinson (Chauffeur’s) fracture
Distal radius fracture of lateral aspect extending into the radial styloid and radiocarpal joint.
Perilunate vs lunate dislocation
Perilunate = capitate dislocation
Lunate = lunate dislocated volarly, but capitate is aligned with the radius
Scapholunate ligament injury
Definition
Cause
Complication
Capitate migrates proximally to fill the gap between scaphoid and lunate
Caused: FOOSH
Complication: scapholunate advanced collapse wrist (this can also be caused due to other things)
What’s the best view for Triquetral fracture
Best seen on lateral radiograph as avulsion fragment dorsal to the triquetrum
Keinbock disease
Avascular necrosis of the lunate
Associated w/ negative ulnar variant
Mallet finger
Distal phalanx, may have avulsion fragment of the distal phalanx, DIP joint flexion.
Boutonniere deformity
Defintion
Association
Medial slip (entrapment of the tendon), fixed flexion of the PIP
Associated w/ RA, may be post traumatic
Gamekeeper’s thumb (skier’s thumb)
Injury to the ulnar collateral ligament at the base of the thumb; proximal phalanx.
Thumb is forced abduction.
May have avulsion fragment of the proximal phalanx.
What is this sign and what does it indicate?
Terry Thomas sign, increased distance of the scapholunate interval indicating scapholunate ligamentous injury
Bennett fracture
Intra-articular fracture of the base of the thumb metacarpal
Rolando fracture
Comminuted bennett fracture
Boxer’s fracture
Metacarpal neck fracture, likely 5th
Volar plate fracture
Avulsion fracture of the volar aspect of the proximal phalanx.
What is the hallmark of arthritis and how is this depicted on radiographs?
Hallmark: Cartilage destruction
Radiographs: Joint space narrowing
What are the types of arthritis?
- Degenerative
- Inflammatory
- Crystal
- Hematological
- Metabolic
Osteoarthritis/osteoarthrosis/degenerative joint disease
KEYWORDS
- Osteophytes
- Subchondral cysts
- Asymmetrical joint space narrowing
- Subchondral sclerosis
Note: No erosions
DDx for extensive subchondral cystic changes seen in osteoarhtirits
Calcium pyrophosphate dihydrate crystal deposition disease.
Osteoarthritis distribution in the following:
Hand
Foot
Knee
Spine
Hip
Sacroiliac joint
Hand: 1st CMC, PIPs, DIPS
Foot; 1st Metatarsal phalangeal
joint, talonavicular joint.
Knee; Asymmetric involvement of the medical tibiofemoral compartment, severe osteoarthritis can involve all the 3 compartments.
Spine; facet joint, atlantoaxial, uncovertebral disc, costovertebral and sacroiliac (synovial joints)
Hip; superolateral migration is classic or inferiomedial
Sacroiliac joint; only the inferior portion of the sacroiliac is synovial.
Vacuum phenomenon is pathognomonic for but don’t confuse with
Vacuum phenomenon = pathognomonic for degenerative but don’t mistake for Kummel disease = gas in the vertebral body due to compress fracture representing osteonecrosis.
Complications of osteoarthritis within the spine.
- Spinal stenosis
- Neural foramina narrowing 3. Degenerative spondylolisthesis
What’s a differential for osteoarthritis in the spine?
Diffuse idiopathic skeletal hyperostosis = DISH
Bridging anterior osteophytes and ossification of the posterior longitudinal ligaments. DISH = CT, not MRI.
Erosive arthritis
Demo
Location
Distribution
Features
Demo: Elderly Females
Location: Only hands
Distribution: Like osteoarhtirits
Features: Like rheumatoid
What is this sign and what does it indicate?
Gull wing sign; erosive arthritis
What is the first location where rheumatoid arthritis hit?
Feet first
What are the features for rheumatoid arthritis?
- Marginal erosions which occur first in the bare area
- Soft tissue swelling
- Symmetric joint space narrowing 4. Periarticular osteopenia
- Joint subluxation/Ankylosing complication
Rheumatoid involvement of the
Hand
Feet
Hip
Knee
Spine
Shoulder
Hand; symmetric, MCPs, PIPs, carpals
Feet: MTPs
Hip; Causes concentric cartilage loss so causes axial migration, if severe it’s called protrusio acetabuli
Knee; All 3 compartments are affected
Spine; involved in more advanced disease, mostly the cervical spine, features; subluxation, osteopenia, erosions of odontoid, end plates, spinous process and facet joints, no bone production
Shoulder; erosions in the lateral head of the humerus, and “penciling” of the distal clavicle causing chronic rotator cuff tears = high riding humerus.
What are the features of rheumatoid arthritis in the knee
Erosions are not prominent, however there is symmetrical joint space narrowing and possibly secondary OA especially if the patient is young.
There are two complications of RA:
Joint subluxation and ankylosing.
Give examples of joint subluxation
1) Boutonniere deformity; PIP flexion, DIP hyperextension
2) Swan neck deformity; PIP hyperextension and DIP flexion
3) Ulnar subluxation at the MCPs
What are the four spondyloarthropathies?
- Ankylosing spondylitis
- Psoriatic arthritis
- Reactive arthritis (Reiter’s) 4. Inflammatory bowel disease associated arthropathy
What is the hallmark for spondyloarthropathies, it’s association and hos it can be differentiated from OA
Association:- HLA B27 positive
Hallmark; - Sacroilitis, first involving the ilias aspects of the joint making it distinctive.
Ankylosing spondylitis
Demo
Features
Location
Demographic; young male associated with lung fibrosis, aortitis
Features; widening, erosions, sclerosis
Location: Stats in the SI joint and moves up the spine
What are the 5 possible appearances of ankylosing spondylitis in the spine
(1) Romanus lesion = erosion of the anterior superior or anterior inferior edges of the vertebral endplates caused by enthesis sclerosis = shiny corner.
(2) Bamboo spine = syndesmoses
(3) Dagger spine = fusion of the spinous process
(4) Squaring
(5) Andersson lesion = pseudoarthrosis in a completely ankylosing spine after fracture
Psoriatic arthritis hallmark
diffuse soft tissue swelling of the digit = sausage digit
Psoriatic arthritis features
- Preserved mineralization
- Various patterns
Psoriatic arthritis
1) SI joint; Bilateral, asymmetric involvement of the SI joint
2) Hand; PREDOMINANT, pencil in cup erosions = DIPS usually
3) Hand rare presentation; Main en lorgnette; opera- glass hand; telescoping of the digits seen in the severe pattern arthritis mutilans
4) Foot; Plantar calcaneal spur with periosteal reaction
5) Spine; coarse bony bridging indistinguishable from reactive arthropathy.
Reactive arthropathy pt history
cervitis, diarrhea, urethritis
Difference between reactive and psoaritic arhtirits
Psoriatic = predominant hand involvement
Reactive = predominate feet involvement
Features of reactive arthropathy
- Soft tissue swelling
- Joint space narrowing
- Aggressive marginal erosions
- Juxta articular osteopenia however bone mineralization is preserved in the later stage.
Psoaritic features in the foot are similar to
rheumatoid arthritis,
however calcaneal spur formation like reactive arthritis
Reactive arthritis involvement
- Foot; calcaneus is common site of involvement; fluffy periosteal reaction, secondary Achilles tendinitis.
- Hands; MTPs, DIPs, PIPs (same distribution of RA)
- Spine; coarse bony bridging indistinguishable from psoraitic arthropathy.
Features of SLE and differential diagnosis
Reducible subluxation of the MCPs and PIPs more apparent with Norgaard (ball catcher) or oblique views.
Ddx RA
Scleroderma
Atrophy of the distal soft tissue
Acroosteolysis; resorption of the distal portion of the distal phalanges is characteristic especially with calcification.
DDx for acrosteolysis
- Collagen vascular disease
- Neuropathy
- Thermal injury
- Hyperparathyroidism
- Polyvinyl chloride exposure
Hydroxyappetite deposition disease other name
Calcific tendinitis
Why is HADD asymmptomatic?
Periarticular tissue (tendons) not directly into the joint thus why it’s commonly asymptomatic
Which tendon is commonly affected in calcific tendinitis?
Supraspinatus tendon is most commonly affected
Milwaukee shoulder
Leads to rapid destruction of the rotator cuff and glenohumeral joint.
When can HADD
mimic a prevertebral abscess?
Prevertebral longus coli muscle = neck pain, odynophagia, fever, prevertebral effusion that may mimic prevertebral abscess
Calcium pyrophosphate dihydrate deposition disease
Demo
Associated with
Demo: Pt’s usually 50 years and older
Associated:
Hemochromatosis
Hyperparathyroidism
Hypophosphatasisa
CPPD (chondrocalcinosis)
Wrist
Knee
Hand
Wrist; chondrocalcinosis affects the triangular fibrocartilage complex with advanced disease causing scapholunate advanced collapse = proximal migration of the capitate between the dissociated schaphoid and lunate. This is not specific, it can be seen in trauma or RA.
Knee; patellofemoral compartment affected first, prominent subchondral cysts.
Hands; hook like/drooping osteophytes from the radial aspect of the metacarpal heads isolated to the 2nd and 3rd metacarpals.
DDx of drooping osteophytes
Hemochromatosis = all metacarpal heads
CPPD (chondrocalcinosis) = raidal aspect of the 2nd and 3rd metacarpals.
Gout
Hx
Hallmark
Hx; renal insufficiency, chemotherapy tx, Lesh Nyhan in young patients
Hallmark;
Sharply marginated erosions with overhanding margins associated with soft tissue gouty tophi preserved joint space and bone mineralization.
Hemochromatosis hand involvement
MCPs, hook like osteophytes, with involvement of ALL the MCPs
Acromegaly joint changes
Excess growth hormone => enlargement of cartilage degenerates.
What is this sign and what is the diagnosis?
Shoulder pad sign; Atrophic muscles, bulky soft tissue nodules due to protein deposition in bones, soft tissue and joints.
AMYLOID deposition
What is this sign and what is the diagnosis?
Shoulder pad sign; Atrophic muscles, bulky soft tissue nodules due to protein deposition in bones, soft tissue and joints.
AMYLOID deposition
Hemochromatosis involvement
Knee; Recurrent hemarthrosis = synovial hypertrophy and hyperemia which causes epiphyseal enlargement and early fusion. Characteristic appearance; widening of the intercondylar notch and squaring of the patella
Elbow; Enlarged radial head and widened trochlear notch
Pseudotumor of hemophilia
Benign lesion caused by recurrent intraosseous or subperiosteal bleeding leading to bony scalloping and pressure erosion
DDx of hemochromatosis on imaging
Juvenile idiopathic arthritis may have similar findings especially in the knee and elbow because it causes hyperemia and same pathophys
Juvenile idiopathic arthritis
Demo
Variant
Demo: Children less than 16
Variant: Still disease is a variant of JIA featuring febrile illness, rash, pericariditis.
Hallmark of Juvenile idiopathic arthritis
abnormal bone length/morphology due to hyperemia.
Involvement in JIA
Knee;
1. widening of the intercondylar notch
2. metaphyseal flaring (Erlenmeyer flask deformity)
3. uniform joint space narrowing ddx hemophilia
4. epiphyseal overgrowth and enlargement; “ballooning”
5. premature fusion of the growth plate which may cause brachydactyly (short digit).
Hand; premature closure of growth plates causing brachydactyly.
Hips;
1. symmetrical cartilage space narrowing
2. protrusion deformity (RA)
3. gracile appearance of the femoral shaft.
Spine; ankylosing (AS) /(also in the wrist)
DDx to JIA in the spine
DDx Klippel-Feil syndrome
Neuropathic arthropathy/ Charcot joint defintion
Destructive arthropathy due to lack of sensation causing fragmentation of bone and cartilage.
Hypertrophic charcot joint features
- destruction
- dislocation/subluxation
- debris
- disorganization
- normal mineralization
Atrophic charcot joint
what should you consider
Shoulder involvement
1. humeral head resorption with sharp surgical-like margin
Syringomyelia shoulder be suspected as the cause and can be confirmed by cervical spine MRI.
Sarcoidosis
Lace-like lytic lesions in the middle/distal phalanges.
Bone manifestations are rare.
Differential for subluxation
Nonreducible think RA
Reducible think SLE
Another point: the presence and absence of erosions
How to assess the bone mineral density and what does it help in?
Cortical thickness of the second metacarpal shaft which should be at least 1/3 of the total width of the metacarpal shaft.
Helps distinguish inflammatory from non-inflammatory arthritis.
Osteophytosis DDx
- OA
- CPPD
- Hemochromotosis
Arthritiswith periosteal reaction
Psoriatic arthritis
Reactive arthritis,
Less likely RA
Bone ankylosing
Wrist and spine=
Juvenile idiopathic arthropathy
Advanced rheumatoid arthritis
Ankylosing of the DIPs is a typical finding in psoriatic arthritis.
Chondrocalcinosis
- CPPD
- Hyperparathyroidism
- Hemochromatosis
Calcification of the tendons
- HADD
- CPPD
Soft tissue calcifications + arthritis
- Gouty tophi
- Scleroderma
- Dermato/polymyositis
- SLE
Cartilage spaces
Preserved
Asymmetric
Symmetric
Increased
Preserved; gout
Asymmetric; osteoarthritis and grout (region of gouty tophi and erosion)
Symmetric; inflammatory arthropathy
Increased cartilage space; acromegaly
Wrist Diffuse
- Inflammatory arthropathy
- Post traumatic OA
Erosion types and pathology
Variable; RA
Pencil in cup; psoriatic
Gullwing; erosive osteoarthritis
Overhanding margin; gout
Soft tissue swelling
- Symmetric swelling; RA
- Asymmetric swelling; OA
Heberden and Bourchard - Swelling of entire digit; in hand think psoriatic arthritis/reactive arthropathy vs foot think reactive arthropathy
- Lymph bumpy; gouty tophi, sarcoidosis, amyloid
Types of periosteal reaction and in ascending order the least to most aggressive
Nonaggressive; solid
Aggressive; lamellated/ onion skin i.e
Very aggressive; sunburst/ hair on end
Very very aggressive; codman triangle
Types of bone matrix
Fluffy cloud like; osteoid
Ring and arc/popcorn like; chondroid
Ground glass; fibrous i.e fibrous dysplasia
Fallen fragment
Fallen fragment is seen in a simple (unicameral bone cyst) with pathological fracture
Tumoral calcinosis
Hx
Painless lumps that may cause compression of the adjacent structures, excudate chalky fluid invloving large joints
No erosions or there is no erosion or osseous destruction.
Aggressive lytic lesion
Above 40
Below 20
above 40 = metastasis or multiple myleoma
under 20 = eosinophilic granuloma, infection, Ewing sarcoma, osteosarcoma
Differentiating Ewing vs osteosarcoma
Ewing below 10
Osteosarcoma above 10 with more soft tissue component
Benign incidental bone forming lesions
- Enostosis (bone island), if multiple with kleoids osteopoikilosis
- Osteopathia striata
- Osteoma; cortex or skull/frontal ethmoid sinus
assocition: Gardner syndrome; multiple intestinal polyps
What are the 3 benign osseous lesions
- Melorheostosis
- Osteoid osteoma
- Osteoblastoma
What is this appearance called and what is associated with?
Candle-wax appearance ; thickened and irregular cortex
Associated with Melorheostosis;
How to differentiate a large bone island from osteoblastic mets/osteosarcoma/osteoid osteoma
Bone san is normal
Melorheostosis on bone scan
Intense uptake
Osteoid osteoma
Presentation
Features
Bone scan
Treatment
Presentation:night pain relieved by aspirin in a young adult.
Diaphysis of long bones, leg bones commonly affected
Features: Osteoid surrounded by reactive sclerosis
Bone scan; double density sign
Treatment; radiofrequency ablation
Why is osteoid osteoma difficult to see on MRI?
Edema obscures the lesion
Osteoblastoma
Hx
Mimics
Location
Complication
Hx: young adults with pain not relieved with pain killers
DDx: Same as osteoid osteoma but > 2cm
Location; spine mostly but can occur in the leg bones too!
Complication: Secondary aneurysmal bone cyst especially in the spinal location
Secondary Osteosarcoma
Pagets
Previous radiation therapy
How to differentiate telangiectatic osteosarcoma from aneurysmal bone cyst
MRI nodular component
Primary Osteosarcoma
Presentation
Features
Most common types
Complications
Presentation; young adult, knee pain, lesion within the metaphysis
Featuers; osteoid, aggressive periosteal reaction(codman/sunburst), soft tissue mass
Conventional intramedullary (75%)
Complication: Lung mets with calcificaiton
Benign cartilage forming lesions
- Osteochondromatosis/synovial chondromatosis
- Enchondroma
- Osteochrondroma
- Chondroblastoma
- Chondromyxoid fibroma
Enchondroma
Hx:
Features:
DDx;
Complication;
Multiple;
Hx: patients are old
Features: long bones, medullary, metaphysis with ring arc calcification
DDx; bone infarction, and chondrosarcoma, MRI is required to differentiate between infarction and enchondroma, enchondroma = high on T2
Complication; fracture, malignant transformation
Multiple; ollier and maffuci (+pheliboliths), these syndromes make the risk for malignant transformation much higher.
What’s special about enchondroma in the hand?
Lytic with no matrix
Osteochondroma
Presentation
Features
Complication
Multiple
Presentation; palpable mass, stops growing at skeletal maturity
Features; Pedunculating bony growth continuity of the cortex grows from the metaphysis and away from the epiphysis
Complication; malignant transformation to chondrosarcoma which can be determined if the patient is complaining of pain, MRI; cartilage thickness >2cm
suggests malignant transformation
Multiple osteochondroma = multiple hereditary exostoses
Chondroblastoma
Features
What’s special about it’s condroid matrix?
How is it seen on MRI
Treatment
Features: Located eccentrically, epiphysis, skeletally immature patient, knee/humerus
(Calcified chondroid matrix might not be seen on radiograph however identified on CT)
MRI: Unqiue chondroid lesion; low/intermediate on T2 because most chondroid are T2 hyperintense
Tx; curettage, cryosurgery, radiofrequency ablation
Chondromyxoid fibroma
Location
Features
Chondroid matrix
Eccentric tibia/femoral metaphysis knee
Featurs: sclerosis margin
Rarely demonstrates chondroid matrix
Secondary Chondrosarcoma
- Enchondroma (more common maffuci/ollier)
- Pagets
- Osteochondroma (more common osteochondromatosis)
Features of chondrosarcoma
Medullary
Expansile
Ring and arc chondroid matrix
Thickening and endosteal scalloping
Soft tissue mass
Nonossifying fibroma/fibrous cortical defect/fibroxanthoma
Demo
Location+ features
Name discrepancy
Where does it come from
Young pt
Location + features:
Eccentric, no sclerosis, medullary, diaphysis/metaphysis
Nonossifying fibroma if the lesion is more than 2 cm/symptomatic
Arise from the periosteum
Fibrous dysplasia
WHAT’S SPECIAL ABOUT IT BEING POLYOSTOTIC
Features
Demo: Congenital, non-neoplasic condition of children and young adults
Types: When polyostotic it tends to be unilateral
Features: medullary, diaphysis, central and meta-diaphyseal causing bowing deformity (extreme varus is called shepherd’s crook)
Fibrous dysplasia
Rib/ long bones
Skull base + DDx
Pelvis
Appearance
Associated syndromes (2)
Complications
In the ribs/long bones; indistinct/ground glass
Pelvis; cystic
Skull base; expansile and highly unusal on MRI DDx Pagets but age can help differentiate
McCune-albirght syndrome;
1. polyostotic fibrous dysplasia
2. Precious puberty
3. Café au lait spots
Mazabraud Syndrome;
Fibrous dysplasia with intramuscular myxoma
Complication; fracture
Hemangioma;
when can it cause neruological compromise?
Can be associated with a soft tissue mass causing neurologic compromise.
Look for phleboliths/ soft tissue calcification if it’s not in the bone and it’s within the soft tissue
Angiosarcoma commonly presents with
Lung metastasis
(Pleural disease)
What are the hematopoietic bone lesions
- Giant cell tumor (osteoclastoma)
- Esoinophilic granuloma (Langerhans cell histiocytosis)
- Ewing sarcoma
- Multiple myeloma
- Lymphoma
Giant cell tumor (osteoclastoma)
Demo
Features
Tx
Demo: Skeletally mature patient between 20-40
Features: Epiphyseal lesion, eccentric, end of long bones, arises from metaphysis but crosses the physis and into the epiphysis.
Tx; curettage or mid resection
Langerhan cell histiocytosis
Demo
Skull
Mandible
Spine
Long Bones
Demo: Children (5-10)
Skull; lytic lesion with a “beveled edge” aka hole within hole appearance
Maxilla/Mandible; floating tooth
Spine; vertebra plana (flattening)
Long bones; destructive radiolucent lesion with aggressive lamellated periosteal reaction which may look like lymphoma or ewing sarcoma
Ewing sarcoma
Presentation
Features
Presentation; children/ young adults, male predominance, pain, fever thus DDx include osteomyelitis which is hard to differentiate from Ewing
Features:
permeative bone destruction
aggressive periosteal reaction (lamellated)
soft tissue mass (but less than osteosarcoma)
Ddx for Ewing sarcoma
LCH
Metastatic neuroblastoma
Osteomyelitis
Lamignant Hematopotien
Most common primary bone tumor in patients over 40
AND
why does it not involve the spine pedicles
Multiple myeloma
Comes from the bone marrow thus doesn’t involve the spine parts without marrow like pedicles
Features and DDx of Multiple myeloma
Features: Multiple lytic lesions with the most severe; diffuse myelomatosis with endosteal scalloping
DDX; metastasis help differentiate by bone scan which is negative for multiple myeloma
Lymphoma
Demo
Features
Sign
Demo: adults over 40
Features: Aggressive lytic lesion with associated soft tissue mass
Sign: Ivory vertebra
Lipoma (Benign)
Location
Features
MRI features
Location: Calcaneus/subtrochanteric
Features: central/ring-like calcification is present
Note: Most lipomas contain some non-adipose tissue which does not suggest malignancy
What features can suggest liposarcoma
Large size >10 cm
Thick septations
Nodular soft tissue
Chordoma
Arises from
Location
Features
Malignant lesion from notochord remnant arising from the midline of the axial skeleton
Location: spheno-occipital region, body of C2 or sacrococcygeal location
Features: Highly destructive, irregular scalloped borders, might have calcifications due to necrosis
Lesions of unknown cellular origin
- Simple bone cyst/unicameral bone cyst
- Aneurysmal bone cyst
- Adamantinoma
Simple bone cyst
Demo:
Features:
Complication;
MRI:
Treatment;
Demo: Local disruption of bone growth in children and young adults
Features: The lesion is hollow/ fluid filled, medullary lesion, proximal diaphysis of humerus/femur, no periosteal reaction which differentiates it from an aneurysmal bone cyst as long as there is no fracture.
Complication; highly associated with pathological fracture, fallen fragment sign which is pathognomonic
MRI: fluid-fluid levels
Treatment; intralesional injection with methylprednisolone which promotes bone growth
DDx for MRI features of fluid-fluid levels
DDx
1. Simple bone cyst
2. Aneurysmal bone cyst
3. Giant cell tumor
4. Telangiectatic osteosarcoma
Aneurysmal bone cyst
Demo:
Location
Features:
MRI
Demo: Adolescents and children
Features: Expansile, multicystic lesion
Location: Medulla or cortex unlike simple bone cyst
MRI; fluid fluid levels
Important consideration in aneurysmal bone cyst
Blood filled sinusoids and solid fibrous elements secondary to a pre-existing tumor; thus if you have a high suspicion and the pathology report is ABC then you’re not going to be happy about it.
Adamintinoma
Low grade tumor occurring in the anterior tibia, arising from the cortex
Features: Soap bubble appearance
DDx fibrous dysplasia
Osseous metastasis (3 locations where to raise the suspicion)
Pedicle or posterior vertebral body suggests metastasis
Fracture of the lesser trochanter raise concern for pathologic fracture.
Solitary sternal lesion in a patient with breast cancer is highly predictive of mets
Benign tumor mimics
- Myositis ossificans/ heterotopic bone formation
- Brown tumor
- Osteomyelitis
Myositis ossificans/ heterotopic bone formation
Demo: Underlying history of trauma, even though sometimes trauma may not be remembered or minor.
Features: Peripheral osteoid mass abutting the anterior humeral cortex, usually elbow and thigh because they’re more prone to trauma. Appearance evolves over period of weeks to months
DDx parosteal osteosarcoma how to differentiate; parosteal osteosarcoma more heavily calcified centrally, while myositis ossificans is more calcified peripherally. (Zoning)
Brown tumor
Features: Lytic lesion with a patient with hyperparathyroidism, doesn’t have any specific imaging features but may be difficult to differentiate from giant cell tumor both radiologically and pathologically.
Brown tumor
Fingers
Spine
Fingers: Osteopenia, subperiosteal bone resorption especially 2nd and 3rd middle phalanges and acromial ends of the clavicles.
Spine: If secondary to renal failure, renal osteodystrophy; rugger jersey spine.
Osteitis
Periostitis
Sequestrum
Involcrum
Cloaca
Sinus tract
Brodie abscess
Osteitis =inflammation of the cortex
Periostitis = inflammation of the periosteum
Sequestrum = necrotic bone separated from viable bone by granulation tissue, it needs surgery because it’s a nidus for recurrent infection
Involucrum = living bone surrounding necrotic bone
Cloaca = opening in the involcrum
Sinus tract = opening from the infection to the skin surface
Brodie abscess = subcutaneous osteomyelitis; central lucency and peripheral sclerosis ddx osteoid osteoma.
Osteomyelitis location in children and why?
Metaphsis because of sluggish flow.
Difference between hematogenous and direct inoculation osteomyelitis
Hematogenous = inside out
and vise versa because of the bridging vessels through the physis.
Location of osteomyelitis in infants up to 12 months
Metaphysis, epiphysis and joint
Periostitis is more prominent in children why?
In adults, the periosteum is more adherently attached to the cortex.
Hematogenous osteomyelitis in adults is common in what location
Spine
Chronic drainage sinus predisposes to
squamous cell carcinoma
Osteomyelitis differential in peds
Ewing sarcoma
Neuropathic joint vs diabetic foot osteomyelitis
Neuropathic foot :
1. Midfoot
2. Polyarticular involvement
3. Absence of soft tissue infection
4. Absence of sinus tract
5. Bony cortex intact
vs diabetic foot which is almost always associated with cutaneous ulcer and sinus tract to the bone with the cortex involved often disrupted
When is biopsy warranted in osteomyelitis?
When it’s due to contiguous spread
Usually polymicrobial unlike hematogenous spread with biopsy warranted to ensure proper treatment.
Bow to differentiate chronic from acute chronic osteomyelitis?
active/non-active osteomyelitis but serial radiographs can show development of periosteal reaction
Most common cause of hematogenous spread
Sickle cell
Puncture wound through sneaker
Tuberculosis
Most common cause of hematogenous spread; Staph
Sickle cell; Salmonella
Puncture wound through sneaker; Pseudomonas
Tuberculosis; Spine
How to differentiate osteomyelitis from cellulitis on Tc99m MDP
Positive in all 3 phases
Cellulitis is positive on flow and blow pool and negative in delayed
When is WBC scan correlation with Tc99m MDP study for osteomyelitis not ideal
When the suspected osteomyelitis is within the spine. This is because the WBCs dont get t o the spine to begin with.
Best MRI sequence for osteomyelitis
whats the role of contrast administration
Most important: T1
Gadolinium
1. fluid collections
2. nonenhancing necrotic bone (sequestrum)
Spetic arhtirtis
Septic arthritis: gold standard
Imaging and clinical hallmark
Cause in children;
Complication
IV drug abuser osteomyelitis
Septic arthritis: gold standard is joint aspiration
Imaging and clinical hallmark; joint effusion
Children; think hip by contiguous extension from the proximal femoral metaphyseal osteomyelitis. (((Proximal femoral metaphysis is within the hip joint capsule)))
Complication; if not treated it leads to ankylosing.
Osteomyelitis of the sacroiliac and acromioclavicular joints = think IV drug abuser
Osteoporosis
T score and Z score
T score <-2.5
Z score = age matched women not for osteoporosis
What is Wembergers sign and Pelkin line and pelkin fracture
Osteomalacia
Specific sign
Common sites
Complication
Looser zone (pseudofracture/milkman line) is highly specific, it’s a stress fracture that’s filled with unmineralized osteoid thus appearing as a lucency through the cortex.
Common sites;
1. medial proximal femurs
2. distal scapula
3. pubic bones
Complication; insufficiency fracture.
Findings in acromegaly
Head;
1. enlargement of the frontal sinus
2. thickening of the cranial bones
3. enlarged jaw
Hands;
1. beak-like osteophytes of the metacarpal heads
2. spade-like overgrowths of the distal phalanges
3. Initially joint spaces are widening but may become narrowed later in the disease due to secondary osteoarthritis.
Feet; increased heel pad thickness greater than 24mm
Hallmark of hyperparthyroidism
- Diffuse bony demineralization
- Subperiosteal and subligamentous bone resorption
Findings of hyperparathyrodisim in
Skull
Hands
Clavicle
Knee
Teeth
Anywehre
Everywhere
Complications
Skull; salt and pepper appearance due to trabecular resorption
Hands; subperiosteal resorption of the radial aspect of 2nd and 3rd middle phalanx
Clavicle; subperiosteal resorption of the distal end of the clavicle
Knee; subperiosteal bone resorption medial proximal tibial metaphysis
Teeth; loss of lamina surrounding the tooth socket
Anywhere; brown tumors
Everywhere; osteopenia
Complications: insufficiency fracture and increased propensity for ligaments/tendon rupture.
Renal osteodystorphy
Findings of two other systemic diseases, what are they
Two findings
Two things; abnormal vitamin D (osteomalacia) and secondary hyperparathyroidism from prolonged renal failure.
- Rugger jersey spine; sclerosis of the vertebral body endplates
- Soft-tissue/vascular calcifications are often present
Hypothyrodism findings (usually children)
- Bullet shaped vertebral bodies
- Wormian bones in skull.
- Slipped capital femoral epiphysis
Hypoparathyroidism
Metastatic deposition of calcium i.e
1. subcutaneous tissues
2. basal ganglia
Pseudohypoparathyroidism and pseudo pseudo hypoparathyroidism
what is this
Clinical features
Classic findings
Psuedohypo = parathyroid hormone receptor problem
Pseudo pseudo hypo = PTH normal, PTH receptor normal but the phenotype is indistinguishable form pseudo
Clinically; obese, round facies, short, brachydactyly
Classic findings; short metacarpal either 4th or 5th digit.
Skeletal feature of hyperthyroidism
Accelerated bone maturation
Pagets disease
Demo
Skull
Vertebra
Pelvic
Long bones
Complications
Demo: Older adults, rare in patients under 40
Skull;
phase 1; sharply marginated geographic lytic region called osteoporosis circumscripta
phase 2; cotton wool skull
Vertebral bodies;
1. picture frame vertebral body/ivory vertebrae
Pelvis;
1. asymmetric coarsened trabecular thickening
2. thickening of the iliopectineal and ilioischal lines
3. possible acetabular protrusion.
Long bones
phase 1; proximal articular end into the diaphysis with sharply marginated border; blade of grass/flame shaped margin
progression through phases; causes bowing, coxa vara deformity
Complications;
1. pathological fracture
2. malignant degeneration (osteosarcoma)
3. secondary giant cell tumor
4. secondary osteoarthritis
Hereditary hypophosphatasia (Juvenile pagets), what makees it diffrent then adult pagest?
Epiphyseal sparing
Osteopetrosis
what is this
what does it cause
what appearance does it give in the spine
Deficiency of enzyme carbonic anhydrase = inability of osteoclasts to resorb bone
Diffuse marked sclerosis of skeleton leading to brittle bone with multiple fractures
Vertebral bodies = sandwich/rugger jersey appearance.
Osteopetrosis
what is this
what does it cause
what appearance does it give in the spine
Deficiency of enzyme carbonic anhydrase = inability of osteoclasts to resorb bone
Diffuse marked sclerosis of skeleton leading to brittle bone with multiple fractures
Vertebral bodies = sandwich/rugger jersey appearance.
