Radiology Fractures

Types of bone

cortical- outside of the bone, very solid- brighter on x-ray

trabecular- inside of bone- contains marrow- light gray on x-ray

Simple Fracture

Bone is broken into 2 fragments- proximal and distal

Comminuted fracture- segmental

2 Fragments & in between is a segmental fragment

Comminuted fracture - butterfly

2 fragments resulting in a "V" shaped wedge fragment of bone in between

Comminuted fracture- severe

A crush injury

This results in multiple bone pieces- basically a segmental, buttefrly fracture and simple fracture all in one

Fracture orientation

Transverse- horizontally- avulsion fracture

Longitudinal- vertical- compression fracture

Oblique- diagonally- most common

Spiral- twisting around bone- butterfly fragment & oblique fracture together, need multiple views to see it- TODDLER'S FX

Displacement

The location of the bones relative to each other in a fracture

Always describe the DISTAL fragment relative to PROXIMAL fragment, and use a relative distance estimate as well (1/2 shaft width etc)

*****Always check all views

Compound Fracture

Where fractured bone is sticking out of skin

Very common in Tibia

Bone exposed to non-sterile air

Bone infected- osteomyelitis

Requires- surgical wash out and IV antibiotics

Clavicle displacement

Exception to the rule

Describe the proximal fracture relative to the distal

Neck muscles pull proximal fragment up

Spine displacement- Spondylolisthesis

Exception the rule

Upper vertebral body relative to lower vertebral body

Impaction

Fragments are driven into each other

Foreshortens the affected bone

Override

Where fragments overlap each other

Foreshortens the affected bone

Distraction

Bone fragments pull apart

Can happen when reducing fractures under traction

Ex. Patella

Not usually due to trauma (usually override/ impaction)

Diastasis

Widening of a joint space

Common trauma- Pubic symphsis

Pseudo-gout= CPPD, scaphoid and lunate bones- SLAC wrist

Angulation

Fragments of bone are angled toward each other on one side and away from each other on other

Need to specify what is relative to what

Valgus and Varus angulation

Valgus- deviation medially

Varus- deviation laterally

Hallux valgus

deviation of 1st toe joint- medially

bunion

Joints- articular surfaces

spherical articular surface- head of bone

Knuckle shaped surfaces- condyles

Tendon insertions- ex greater/ lesser tubercule/tuberosity

Intra-articular fracture

Involves articular cartilage

Extends to joints

Risk of secondary OA

Reduction must be anatomic

Extra- articular fracture

Does not involve the joint

Reduction can be relatively anatomic

bones will remodel and heal themselves

Parts of a immature bone

Diaphysis- shaft of the bone

Physis- un-united growth plate

Metaphysis- below the growth plate- bone angles out

Epiphysis- above the growth plate- end of bone

Salter- Harris fractures

All involve the physis

Cannot be skeletally mature- growth plates fused

Risk of premature growth plate fusion and leg length discrepancy

Always compare to opposite side

Salter- Harris fractures I-V

I- Physis only- very subtle

II- Physis and metaphsysis- doesn't extend into joint, most common

III-Physis and epiphysis- does extend into joint, potentially very serious, use CT to assess alignment

IV- Physis, metaphysis, & epiphysis- Obviously crosses joint, evaluation by CT, Distal Tibia- called "Triplane fracture"

V- Physis, metaphysis, & epiphysis- Crushes joint, very high rate of premature growth plate fusion

Bowing (plastic) fracture

Adult bones- brittle, tend to break

Child bones- soft, tend to bend, typically will remodel in time

Greenstick fracture

Incomplete fracture

Fracture only crosses the coritcal bone

More common in children

Torus (buckle) fracture

Commonly seen when an axial load is put on bone

Metaphysis/diaphysis protusion of the cortical bone- outward cortical buckling

Ex. Fall on outstretched hand- common in children- radius

Occult fractures

Not detected on radiographs

Ex:

Places with overlapping structures- cervical spine Do CT

Fractures to non- displaced to see- Femoral neck, Scaphoid- Do MRI

Fractures with no cortical disruption- Stress fractures- Do MRI

Stress fractures

Fatigue

or

Insufficiency

Insufficiency fractures

Normal forces on abnormal bones- Osteroporosis, osteomalacia

Commonly seen- femoral neck, spine, sacrum

Fatigue

Abnormal forces but on normal bone- Athletes, increase activities, change habits

Common in LE- navicular, 2nd metatarsal, femur, tibia

Patient must be compiant for fracture to heal

Tibial fatigue fracture

Commonly seen in athletes

X-ray - usually see nothing

Can see periosteal reaction, trabecular stenosis over time, cortical lunacy- "dreaded black line"- will not heal without surgery

Fatigue factor management

NO MRI

Diagnose by history and exam

Get radiographs- may confirm, may see other problems, making sure it is not a complete fracture

Treat- stop/change activities, hard soled shoes

Stress fractures

Use MRI

See marrow edema, periosteal reactions

When to do them

Fatigue fractures in patients that refuse to stop

Insufficiency fractures in osteoporotic pts

MRI staging Tibial fracture

4 stages

1. Periosteal reaction only - shin splints

2. Marrow edema- most sensitive- T2 with fat suppression

3. Marrow edema- most specific- T1

4.Line through cortex

Fractures not to miss

Femoral neck

Scaphoid fracture

Femoral neck fracture

Common in osteoporotic patients

Detect non-displaced (percutaneous pinning) vs displaced (hip replacement)

Scaphoid fracture

High rate of non-union, avascular necrosis

Diagnosis is made primarily by exam

Snuffbox Tenderness = Presumed Scaphoid