Week 7: Fractures
What two ways may an avulsion fracture occur?
- Eccentric contractions in acute setting - Repetitive microtrauma can cause chronic avulsion fracture
What is the MOI of a meniscus tear?
- Occur during shear, rotary, and compression forces that abnormally stress the fibrocartilaginous tissues. - They are a common sports injury, and in the older population owing to degenerative processes.
What are the 4 different types of fractures?
- Open: any time the skin is perforated (AKA compound) - Closed: skin and soft tissues overlying fracture are intact - Complete: all cortical margins are broken. (comminuted = multiple pieces more than 2). - Incomplete: one portion of the cortex is disrupted
What are the risk factors for a non-union? (7)
- Smoking - Older age - Low vitamin D - Diabetes - Poor nutrition - Poor blood supply - Medications: NSAIDs *SOLD PPM
There are 4 steps in the process of bone repair, what are they?
- Step 1: Hematoma and bone death - Step 2: Fibrocartilaginous callus - Step 3: Bony callus - Step 4: Bone remodeling (several months to a year +)
How does a cyst appear on a T1 and T2 MRI? A. high B. intermediate C. dark
- T1 MRI: low signal because of fluid (fat is bright, fluid is dark) - T2 MRI: high signal because of fluid (fat is dark, fluid is bright)
What type of imaging is used for cruciate ligament tears?
- X-rays (radiographs): are required to rule out potential avulsion fractures at the sides of the cruciate attachment. - Sagittal MRI: shows disruption in the linear continuity of the ACL in complete tears. Partial tears show thickening and disruption of some fibers.
How would you distinguish if a fracture is complete or incomplete?
- complete: involves both cortices or one bone now has 2 fragments
Which type of union is most often seen with pathological factors? What are those factors?
- delayed union - Loss of bone structure - Infections - Interrupted immobilization - Disrupted or low vascularity *LIID
What 3 things can occur when normal healing doesn't proceed correctly?
- delayed union: present when a fracture fails to unite in the time frame normally required - non union: occurs when bone fragments have failed to unite and the process of bone healing has stopped - mal union: fracture that has united, but has an angular/rotary/ or other deformity
How is the alignment of a fracture named?
- describe distal fragment to proximal region - medial/lateral, varus/valgus, rotated/shortening/angulation
What are two types of incomplete fractures?
- greenstick fracture: occurs when a bone bends and cracks, instead of breaking completely into separate pieces. - torus (buckle) fracture: occurs when there is a wrinkling of the outer edge of the bone due to compression, usually after a fall.
How would you know if a fracture is intra-articular or extra-articular?
- intra-articular fractures will have a perpendicular fracture going into the joint. Extra-articular fractures will not.
When looking at the femur, what are the directions that the fragments can move?
- lateral - medial - proximal (towards head of femur) - distal (towards condyles)
When looking at describing fractures, how are long bones named?
- long bones are divided into thirds. I.e. proximal, middle, distal third
What is the difference between a periosteal and endosteal (medullary) callus?
- periosteal callus: bony callus around the ends of a fractured bone (surrounds fx) - endosteal callus: in medullary cavity (inside of long bones)
How are fractures described/defined? (5)*
- site and extent: location - special types: bome pathologies - articular regions: extra-articular vs intra-articular - type: complete vs incomplete - alignment: distal to proximal relationship - avulsion: ligaments or tendons cause a fracture
What occurs during step 4, bone remodeling?
- spongy bone is replaced by compact bone - the fracture line disappears but evidence of the break remains
What are the different types of fractures? (4)
- transverse fracture - oblique fracture - butterfly fracture - spiral fracture
What is the MOI for cruciate ligament tears?
- various types of valgus, rotatory, and hyperextension moments with or w/o contact and with the knee in any position from flexed to fully extended.
For a simple hand fracture, what is the general healing type for bone repair?
4-6 weeks
T1 (fat is bright, fluid is dark)
A cyst is circled in the following image, what type of MRI is it?
If a fracture is defined as having the skin and soft tissues overlying the fracture intact, what is that termed? A. closed B. complete C. incomplete D. open
A. closed
Compression or a sharp blow from an angle may cause what type of fracture? A. oblique fracture B. transverse fracture C. spiral fracture D. butterfly fracture
A. oblique fracture
If a fracture is defined as having all the cortical margins broken and there is complete disruption in continuity of bone, what is that termed? A. closed B. complete C. incomplete D. open
B. complete
Tension on a bone produces what type of fracture? A. oblique fracture B. transverse fracture C. spiral fracture D. butterfly fracture
B. transverse fracture
If a fracture is described as having one portion of the cortex disrupted, what is that termed? A. closed B. complete C. incomplete D. open
C. incomplete
If a patient presents with plain radiographs showing bone trabeculae or cortical bone crossing the fracture site, what type of union is present? A. mal union B. non union C. radiographic union D. clinical union
C. radiographic union
Compression and bending may produce which type of fracture? A. oblique fracture B. transverse fracture C. spiral fracture D. butterfly fracture
D. butterfly fracture
If a patient presents with no evidence of motion under stress and potential for little to no pain in a fracture, what type of union is seen? A. mal union B. non union C. radiographic union D. clinical union
D. clinical union
If there is a callus seen on an x-ray uniting the fracture site, but a radiolucent band remains suggesting that repair lacks normal strength, what type of union is that termed? A. mal union B. non union C. radiographic union D. clinical union
D. clinical union
If a fracture is described as the skin being perforated, what is that termed? A. closed B. complete C. incomplete D. open
D. open
Which of the following is closely related to a compound fracture? A. closed B. complete C. incomplete D. open
D. open
A. comminuted B. medial displacement C. proximal
How is the following fracture in the image classified? Select the correct answer from the pair. A. complete or comminuted B. medial or lateral displacement C. proximal or middle 1/3
A. complete B. oblique C. lateral displacement D. middle 1/3 E. shortening
How is the following fracture in the image classified? Select the correct answer from the pair. A. complete or incomplete B. transverse or oblique C. medial or lateral displacement D. proximal or middle 1/3 E. angulation or shortening
extra-articular fracture
Is the image showing an extra-articular or intra-articular fracture?
intra-articular fracture
Is the image showing an extra-articular or intra-articular fracture?
What is the STANDARD for imaging a meniscus tear?
MRI
Why is an MRI the standard for imaging of a meniscus tear?
Tears are seen as a high signal intensity that extends to the surface of the normally low signal intensity meniscus
bony callus
What is seen in the following image?
overriding (shortening) distal radial fracture and ulnar metaphysical fracture
What is seen in the image?
D. clinical union
What is seen in the image? A. mal union B. non union C. radiographic union D. clinical union
X. radiographic union with a bony callus
What is seen in the image? A. mal union B. non union C. radiographic union D. clinical union
PCL avulsion fracture
What is seen in the images?
C. radiographic union
What is seen in the x-ray? A. mal union B. non union C. radiographic union D. clinical union
complex tear of the lateral meniscus
What is seen in this image?
cyst
What is seen in this image?
tear of posterior horn of the medial meniscus
What is seen in this sagittal PD?
oblique fracture with spiral components
What type of fracture is seen in the following image?
extra-articular, displaced
What type of fracture is seen in the following image? *
extra-articular, non displaced
What type of fracture is seen in the following image? *
intra-articular, displaced (perpendicular line is going words joint space)
What type of fracture is seen in the following image? *
intra-articular, non displaced
What type of fracture is seen in the following image? *
complete fracture
What type of fracture is seen in the image, complete or incomplete?
D. butterfly fracture
What type of fracture is seen in the image?
avulsion
What type of fracture is seen in the image?
clinical union
What type of fracture is seen in the image?
comminuted fracture (more than 2 pieces)
What type of fracture is seen in the image?
greenstick fracture
What type of fracture is seen in the image?
incomplete
What type of fracture is seen in the image?
open/compound fracture
What type of fracture is seen in the image?
torus (buckle) incomplete fracture
What type of fracture is seen in the image?
A. oblique fracture
What type of fracture is seen in the image? A. oblique fracture B. transverse fracture C. spiral fracture D. butterfly fracture
angulated forearm fracture
What type of fracture is seen?
B. transverse fracture
What type of fracture is seen? A. oblique fracture B. transverse fracture C. spiral fracture D. butterfly fracture
- complete PCL tear - sagittal T2w
What type of tear is seen in this image? What type of imaging is used?
- complete tear of ACL - sagittal T1w
What type of tear is seen in this image? What type of imaging is used?
- partial ACL tear - axial PD
What type of tear is seen in this image? What type of imaging is used?
clinical union
What type of union is seen in the image?
delayed union
What type of union is seen in the x-ray?
distraction without displacement or angulation
When looking at the femur, if the displaced fragment moves away from the proximal fragment, how is that termed?
complete (100%) lateral displacement with shortening and without angulation
When looking at the femur, if the distal fragment is displaced like so, what is that termed?
complete medial displacement with shortening and lateral angulation
When looking at the femur, if the distal fragment is displaced like so, what is that termed?
lateral angulation without displacement *(because distal fragment is in line with proximal fragment, didn't move prox/dist or med/lat) *Lateral angulation because condyles angled laterally
When looking at the femur, if the distal fragment is displaced like so, what is that termed?
lateral displacement and lateral angulation
When looking at the femur, if the distal fragment is displaced like so, what is that termed?
lateral displacement without angulation
When looking at the femur, if the distal fragment is displaced like so, what is that termed?
mal union
Which type of union is seen in the image?
non union
Which type of union is seen in the image?
What is the definition of a fracture?
a break in the continuity of bone or cartilage
How does step 2 of bone repair, fibrocartilaginous callus appear on an x-ray?
a haze that is not quite as bright as a bony callus
Eccentric contractions in an acute setting cause what type of fractures?
avulsions
What is the final step of bone healing that can take several months to a year + depending on a multitude of factors as well as type of bone involved?
bone remodeling
How would a cyst appear on a bone scan (scintigraphy)?
bright
How does step 3 of bone repair, bony callus, appear on an x-ray?
brighter haze around fracture than a fibrocartilaginous callus
What are features of a cyst?
clear serosanguineous fluid surrounded by thin fibrous lining
How does step 1 of bone repair, hematoma and bone death appear on an x-ray?
dark
Which type of union is present when a fracture fails to unite in the time frame normally required?
delayed union
What type of fracture occurs because of a bone bending and cracking, instead of breaking completely into separate pieces?
greenstick incomplete fracture
How does a cyst appear on a CT?
hypodense *similar to plain x-ray but has advantage of characterizing extent
What type of union involves a fracture that has united, but has an angular/rotary/ or other deformity existing?
mal union
Which type of union occurs when bone fragments have failed to unite and the process of bone healing has stopped?
non union
What is the most common benign bone tumor in people under 20?
non-ossifying fibroma *most may be asymptomatic * often found when imaging other concerns around the knee
For a child or adult who is > 1 year old who sustained acute trauma to the knee with a MOI of a fall or twist injury, with no focal tenderness, no effusion, and is able to walk, what is the BEST type of imaging that should be used?
none are appropriate
What may cause chronic avulsion fractures?
repetitive microtrauma
What is meant by the term overriding?
synonym for shortening (seen with fractures)
What type of fracture occurs when there is a wrinkling of the outer edge of the bone due to compression, usually after a fall?
torus (buckle) incomplete fracture
What property of bone allows for deformation without fracture in many cases?
viscoelastic properties
If a humeral fracture was suspected what imaging modality would be used?
x-ray
For a child or adults who is > 1 year old who sustained an acute trauma to the knee with a MOI of a fall or twisting injury, with 1 or more of the following: focal tenderness, effusion, inability to WB, what is the BEST type of imaging that should be used?
x-ray of the knee (9)
