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
***
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
What type of hip dislocation is most common?
Posterior dislocation, 90%
In a posterior hip dislocation, where does the femoral head lie anatomically?
Femoral head lateral and superior to the acetabulum
What two other injuries may be associated with a posterior hip dislocation?
- Posterior rim of acetabulum is usually fractured
- Sciatic nerve injury (10%)
In an anterior hip dislocation, where does the femoral head lie anatomically?
Femoral head displaced into the obturator, pubic, or iliac region
In an Internal hip dislocation, where does the femoral head lie anatomically?
What fracture is ALWAYS associated with this dislocation?
Femoral head protrudes into pelvic cavity
Always associated with acetabular fracture
What is the name given to Tibia plateau fractures?
Are these due to direct or indirect trauma?
Bumper Fracture - due to direct trauma
What are the 3 locations of a tibia plateau fractures?
How common is each?
- Lateral plateau fracture (80%) is more common because most trauma results from valgus force
- Medial plateau fractures (10%)
- Combined medial and lateral fractures (10%)
What classification system is used for Tibia plateau fractures and explain each?
Schatzker Classification (orthobullets - slide info on image)
I ➞ Lateral split fracture
II ➞ Lateral Split-depressed fracture
III ➞ Lateral Pure depression fracture
IV ➞ Medial plateau fracture
V ➞ Bicondylar fracture
VI ➞ Metaphyseal-diaphyseal disassociation
Why may plain films not be best for tibial plateau fractures?
What is often used instead?
Fractures of tibial plateau may not be obvious; plain films often underestimate the true extent of fractures and therefore a CT is often necessary
What may be visible on a cross-table lateral view of a tibia plateau fracture?
Fat-fluid interface sign OR Fat-blood interface sign (FBI)
Fat (marrow)-fluid (blood) interface sign (hemarthrosis)
What type of tibia plateau fracture is shown below?
Type I
What type of tibia plateau fracture is shown below?
Type II
What type of tibia plateau fracture is shown below?
Type III
What type of tibia plateau fracture is shown below?
Type IV
What type of tibia plateau fracture is shown below?
Type V
What type of tibia plateau fracture is shown below?
Type VI
What is an avulsion fracture?
How does it manifest radiologically?
An avulsion fracture involves the detachment of a bone fragment that results from the pulling away of a ligament from its point of attachment on a bone
This type of injury often manifests radiographically as a tiny osseous fragment located adjacent to the expected attachment site of ligament
What is a Segond Fracture?
What is its mechanism of injury?
A small cortical avulsion fracture of proximal lateral tibial rim just distal to lateral plateau
Mechanism: external rotation + excessive tension on the lateral capsular ligament
A Segond Fracture is associated with what 2 other injuries
- lesion of anterior cruciate ligament (75-100%)
- meniscal tear (67%)
What are the 4 types of Patellar fractures we can have?
Highlight which is the most common
- Vertical fracture
- Transverse (most common)
- Comminuted
- Avulsed
List 3 ways we can differentiate a multipartite patella from a fractured patella?
- Bipartite or multipartite patella is typically located at the superolateral margin of the patella
- Individual bones of a bipartite or multipartite patella do not fit together as do the fragments of a patellar fracture
- The edges of bipartite or multipartite patella are well corticated
Revise ligaments of the ankle
What 3 ligaments support/form the ankle syndesmosis?
Anterior inferior tibiofibular ligament (AITFL)
Posterior inferior tibiofibular ligament (PITFL)
Transverse ligament
What classification system is used for Ankle fractures?
Explain this
Weber A, B, C
A ➞ fibular# below the syndesmosis, which is intact
B ➞ fibular# at the level of syndesmosis (trans-syndesmotic) Usually partial or less commonly total rupture of the syndesmosis
C ➞ fibular# above the syndesmosis. Usually a total rupture of the syndesmosis, and consequently instability of the ankle mortise
What is the importance of X-rays and classification of Ankle fractures?
Management decisions are based on the interpretation of the AP and lateral X-rays
Classification of ankle fractures is important in order to estimate the extent of the ligamentous injury and the stability of the joint
What is the medial and lateral clear space (radiographic measures)?
What value is abnormal and what is its clinical significance?
MCS = space between lateral edge of medial malleolus and medial side of talus. >4mm is abnormal, prediction of deltoid ligament injury
LCL = space between medial border of fibula to lateral border of posterior tibia 1cm above the tibial plafond. Widening >5-6mm is abnormal, indicates syndesmotic rupture
The ankle can be thought of as a ‘ring’, explain this and its relevance to stability of the rupture
If the ring is broken in one place the ring remains stable
When it is broken in two places, the ring is unstable and may dislocate
When both the medial and the lateral malleoli are fractured it is unstable
Describe a type A webber fracture in terms of:
- location
- mechanism
- other associated injuries
- prognosis
Describe a type B webber fracture in terms of:
- location
- mechanism
- other associated injuries
- prognosis
Describe a type C webber fracture in terms of:
- location
- mechanism
- other associated injuries
- prognosis
What fracture is shown below?
Webber C?
What fracture type is shown below?
Webber C?
What fracture is seen below and what is its most common mechanism of injury?
Calcaneal Fracture (60% of all tarsal fractures)
Results from axial load (e.g., fall from height)
List 3 Radiographic features of a calcaneal fracture
- Decreased Boehler’s angle < 20h (normal Boehler’s angle does not exclude fracture)
- 75% are intraarticular (subtalar joint), 10% are bilateral
- May be associated with lumber fractures ???
What is Boehler’s angle?
Angle between upper border of the calcaneal tuberosity and a line between the anterior and posterior articulating facets
- Normal value = 20°-40°
- A value < 20° = calcaneal fracture
BUT a decreased Böhler angle may normal and a normal Boehler’s angle does not exclude a calcaneal fracture
What type of fracture is shown below?
What is this fracture also known as?
Transverse fracture at base of 5th metatarsal distal to metatarsal tuberosity > 1.5 cm from proximal tip
“Dancer’s fracture”
????
What is apophysis of the proximal 5th metatarsal?
Apophysis of 5th MT base appears on plain radiographs at age 12 for boys and 10 for girls.
Fusion of apophysis to the MT base usually occurs within the following 2-4 years
Do NOT confuse fracture with Apophysis (image)
