Di Imaging II - Exam 2 (Extremity Trauma)

Types of fractures

transverse, oblique, spiral, comminuted, greenstick, avulsion

Incomplete fractures

greenstick and torus

Forces involved in production of fx

angulation (transverse fx)

compression/impaction (oblique fx)

rotation (spiral fx)

shear

tension (transverse fx)

Transverse fx typically result from

direct blows or tensile forces

• pathologic bone conditions

Oblique fx typically result from

angulation and compression

Spiral fx typically result from

torque and axial compression

• ends are pointed like a pen

Distal fragment compared to proximal fragment

ALWAYS

What type of fx is this

spiral fx of distal tibia w/posterior displacement

What type of fx is this

spiral fx with overriding deformity, posterior and lateral displacement and rotational misalignment

Alignment

describes the ANGULATION of the distal fragment at the fx site

Apposition

describes the CLOSENESS of the bony contact at fx site

What type of fx is this

transverse fx of distal radius, good apposition (heal easier)

Epiphyseal (weakest part of bone) injuries are MC btw the ages of

10-16yo and elderly

Three phases of healing

inflammatory/circulatory phase

reparative/metabolic phase

remolding phase

The first radiographic visualization of a Callus formation is

14 days

Clinical union

callus is sufficiently developed to allow weight bearing

What is the MC complication of a fx

non-union

Salter-Harris Fx (involving active physis/growth plate) types

1 = complete shear injury of physis

2 = fx through physis and metaphysis

3 = fx through physis and epiphysis

4 = fx through physis, metaphysis, epiphysis

5 = compression fx of physis

What is the MC Salter fx

type 2

What is the LC Salter fx

type 5

What should you do to confirm if someone has a Salter fx

x-ray the other extremity to compare

Salter 1

wide growth plate and soft tissue swelling

Salter 2

metaphyseal fragment = Thurston Holland sign

Salter 3 and 4 are

intraarticular

What is the dx

osteopetrosis and Salter type 2

Normal AC width

<5mm

Normal distance btw coracoid and clavicle

11-13mm

Grade 1 AC sprain

slight widening btw acromion and clavicle w/o elevation

acromioclavicular ligament stretched/partially torn

Grade 2 AC sprain

acromioclavicular ligament completely torn

coracoclavicular ligaments intact

Grade 3 AC sprain

acromioclavicular ligament and coracoclavicular ligament completely torn

• >50% displacement

• 100% elevation

What is the MC fx to occur during birth

clavicle fx (MC middle 1/3)

Complication of clavicle fx

post traumatic osteolysis (resorption of clavicle)

Transverse mid-clavicle fx can get an

overhanging/bayonet deformity

Three subcategories of anterior shoulder dislocations

subcoracoid, subglenoid, intrathoracic

What is the MC anterior shoulder dislocation

subcoracoid anterior shoulder dislocation

Bankart lesion

fx through ANTEROINFERIOR labrum involving inferior bony glenoid

Hill Sachs defect

impaction fx of humeral head and glenoid fossa

notch like defect of SUPEROLATERAL aspect of humeral head

What does a hill sachs suggest is in a pt’s history

previous anterior shoulder dislocation

What is the dx

anterior subcoracoid shoulder dislocation w/flap fracture

Posterior shoulder dislocation

Rim sign = widening of joint space >6mm

Trough line sign = impaction fx of anterior medial humeral head on posterior glenoid rim

Tennis racqet appearance of humeral head or lightbulb sign

Rotator cuff injury

supraspinatus (MC)

infraspinatus

teres minor

subscapularis

What is the gold standard for dx of RC injury

MRI - tears are usually hyperintense in the tendon on T1 weighted

RC tears are typically located in the

critical zone (decreased vascular supply)

What is the MC fx of elbow in children

supracondylar fx

What is the MC fx of elbow in adults

radial head/neck

Hints to know if elbow has a fx - Fat pads

elevated supinator fat pad

Sail sign = elevated anterior fat pad

can see posterior fat pad

Hints to know if elbow has a fx - Radio-capitellar line (adults)

drawn down middle of radius and should intersect middle 1/3 capitulum

• looks for radius dislocations

Hints to know if elbow has a fx - Anterior humeral line

drawn down anterior cortex of humerus and should intersect middle 1/3 capitulum

• looks for supracondylar fx (via FOOSH/hyperextension)

Which of the two lines drawn to find a fx is very important in kids

anterior humeral line

If there is a positive fat pad sign in children, there is a 90% chance there will be an associated

intraarticular fx

Radial head/neck fractures (chisel fx) are MC in

adults

Ossification centers of the elbow (CRITOE + 1, 3, 5, 7, 9, 11)

capitellum

radial head

internal epicondyle

trochlea

olecranon

external epicondyle

What is the dx

avulsion fx of internal epicondyle

What is the dx

lateral epicondyle avulsion fx

What is the 3rd MC site of dislocation in adults

elbow

What is the MC site of dislocation in children

elbow

What is the MC dislocation of the elbow

posterior/posterior lateral

When an injury to the forearm occurs, the MC fx occurs in

both ulna and radius

A Nightstick fx is a fx of what bone

ulna

A Galeazzi fx is defined as

distal radius fx + slight dislocation of distal radio-ulnar articulation

A Monteggia fx is defined as

ulna fx + anterior dislocation of radius at proximal radio-ulnar articulation

Greenstick fx

incomplete fx

force is greater than torus fx

tendency for re-angulation following initial reduction

What is the MC forearm fx in children 6-10yo (typically in radius)

torus/buckle fx

Normal volar/palmer tilt of radius

10-15 deg anterior

Colles fx

radius fx w/posterior displacement of distal fragment

dinner fork deformity

Colles and Barton’s fx are caused by

FOOSH - typically elderly

Smith’s fx

radius fx w/anterior (volar/palmer) displacement of distal fragment

Smith’s fx are caused by

fall onto the back of the hand

Barton’s fx

posterior rim of radius fx w/carpal dislocation

Hutchinson’s fx/Cheufer’s fx

radial styloid fx

What is the MC carpal fractured

scaphoid (triquetrum 2nd, hamate 3rd)

Scaphoid fractures typically heal without periosteal callus, which means

non-union, slow healing, often gets AVN

Where is the MC site for an occult fx (can’t see it)

scaphoid

Complications with a scaphoid fx

AVN - especially in proximal pole

MUST SAY WHERE FX IS IN SCAPHOID

distal pole

waist (MC)

proximal pole

Steps if suspect a scaphoid fx

take ulnar flexion x-ray

immobilize wrist

repeat x-ray 7-10 days post injury

What carpal fx has a “pooping duck sign” on the lateral wrist x-ray

triquetral