Lower Limb Fractures Flashcards
How to pelvic fractures usually occur?
Usually secondary to massive force, such as a road traffic accident or fall from a height
May be associated with vascular, soft tissue and visceral injuries
When are pelvic fractures considered stable vs unstable?
If the pelvic ring is broken in two places the fracture is likely to be unstable
Isolated ring fractures tend to be stable
How are acetabular fractures classified?
The Judet and Letournel system
Classified as either elementary fractures OR associated fractures (image shows elementary)
What is indicated by the green and blue line?
What is the cinical significance?
iliopectineal line ➞ disruption indicates anterior column fracture
ilioischial line ➞ disruption indicates posterior column fracture
What is the most common Acetabular fracture?
Posterior wall
What radiographic landmark is shown below?
What is the mechanism of injury of an anterior column fracture?
What other injuries are associated with this?
What is the mechanism of injury of a posterior column fracture?
What other injuries are associated with this?
What is a Transverse fracture of the acetabulum?
List 4 muscles commonly involved in avulsion fractures of the lower limb (incl their attachments)
List 3 reasons we are concerned about a femoral head fracture
- Femoral head undergos transmission of most body weight
- Intra-articular bone only has a thin periosteum and no contact with soft tissues. This means the response to injury (callus formation) is weak
- Blood remains inside the joint capsule, increasing intracapsular pressure and further damaging the femoral head; synovial fluid hinders clotting
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List the 3 types of intra vs extra capsular femoral neck fractures
(Hint: based on location)
Intra-capsular fracture
- Subcapital: common
- Transcervical: uncommon
- Basicervical: uncommon
Extracapsular fracture
- Intertrochanteric
- Trochanteric
- Subtrochanteric
An intracapsular fracture is also known as what?
In which age group is this particularly dangerous?
A high fracture of the neck of femur
This is a serious injury in the elderly patient
Why is an intracapsular fracture so dangerous?
Blood supply to NOF is retrograde (distal to proximal) along femoral neck to the femoral head. This is predominantly through the medial circumflex femoral artery
A displaced intra-capsular fracture disrupts the blood supply to the femoral head which can result in AVN
_____ is the most useful test for evaluating bony injury.
However, _____ fractures in the plane of the images can on occasion be missed with this imaging method
CT, axial
(This potential is decreased with the use of images reconstructed in orthogonal planes and newer multi- detector CT scanners)
What is the imaging modality of choice for detection of femoral neck fractures and why?
MRI
It is both sensitive and specific in detection of NOF#, because it shows both the actual fracture line and the resulting bone marrow edema
MRI is the most sensitive modality in detecting bone marrow changes related to AVN, even when radiographic findings are normal
An extra-capsular fracture is also known as what?
How can these be classified?
Low fractures
classified as stable or unstable fractures
Compare union of an intracapsular vs extracapsular NOF fracture with reason
Intracapsular ➞ the proximal fragment often loses part of its blood supply and hence, the union of this fracture is difficult
Extracapsular ➞ blood supply to the proximal fragment is not interfered hence the fractures unite easily
What deformity may be seen with an extracapsular NOF fracture?
How is this deformity defined?
While union is the rule, it is common to see these fractures mal-united with a coxa vara deformity
- Normal neck shaft angle is ~115o
- When angle is reduced to ~90o = Coxa Vara
Compare a stable vs unstable extracapsular fracture
Stable Type: There is a single fracture line and it is a two piece fracture.
Unstable Type: This is a comminuted fracture with multiple fractures at the trochanteric level
Compare the following regarding Intra vs Extracapsular fractures
Femoral shaft fractures are described according to what 3 things?
- Location ➞ proximal, middle, and distal thirds
- Pattern ➞ comminuted, spiral, oblique, or transverse
- Degree of comminution
Femoral fractures often present with multisystem trauma, what 3 things MUST we consider/evaluate with any fracture
- Amount of blood loss (do not underestimate)
- Compartment syndrome, rare but important
- Fat embolism syndrome (FES) and acute respiratory distress syndrome (ARDS)
How long following a fracture does FES usually occur?
Typically 24-72 hours after the traumatic event
What is the classic triad associated with FES?
- Respiratory changes ➞ fat emboli damage small vessel perfusion with resulting damage to the pulmonary vascular bed
- Neurological abnormalities ➞ cerebral embolism
- Petechial rash ➞ embolization of small dermal capillaries