Trauma Imaging of Lower Limb Flashcards
(57 cards)
What are lower limb fractures associated with?
High morbidity and mortality
Immobility = pneumonia, DVT/PE, dehydration/starvation
What are the limitation of x-rays when imaging fractures?
Can’t visualise through overlapping structures
May not be shown on standard x-ray projection
Fracture is undisplaced
Can’t capture soft tissue structures
Why are CT scans useful for imaging fractures?
Cross sectional = unaffected by overlapping structures and can show fractures irrespective of their plane
Why are MRI scans useful for imaging fractures?
Provides detailed info about bone marrow so can show undisplaced fractures
What techniques can be used to image soft tissue injuries?
US = high resolution images of superficial structures, especially tendons MRI = high resolution images of all structures, even those deep inside body or within joints (areas where US struggles)
What are some features of lower limb fractures?
Often involve axial force with bone impaction = may appear sclerotic
Typical sites of impacted fracture = femoral neck, tibial plateau, calcaneus
What are some features of high energy pelvic ring fractures?
Often young people, associated with RTA or fall from height
Bony ring disruption usually affects more than one site so usually multiple (either bones of symphysis)
How are high energy pelvic ring fractures imaged?
X-ray if pelvis is only site of injury
CT is primary test for polytrauma patients
What are some features of low trauma pelvic fractures?
Affect elderly patients with osteoporosis, typically due to minor fall or may be of insidious onset
Multiple fractures often present = typically sacrum and pubic rami
How are low trauma pelvic fractures typically imaged?
X-rays often normal = CT better than x-ray especially once fractures start to heal
MRI is better than CT so is test of choice
What are some features of pelvic soft tissue injuries?
Sports related
Acute causes = muscle tear or tendon avulsion
Chronic overuse can cause bone/soft tissue pain at site of tendon/ligament attachment
How are pelvic soft tissue injuries imaged?
US = shows acute injuries affecting superficial structures MRI = gold standard, provides more complete assessment of all soft tissues and bones
What are some features of an acute hamstring tendon avulsion?
Commonly sports related, cause of acute pelvic injury
What are some features of a hip dislocation?
Result of RTA or contact sport where hip is flexed
Typically posterior, with acetabular rim fracture
May be complicated by femoral head AVN or early OA
How are hip dislocations imaged?
CT = details anatomy to help with surgical planning
What are the two classifications of proximal femoral fractures?
Intracapsular and extracapsular
What are some features of intracapsular proximal femoral fractures?
Interfere with blood supply to femoral head
Prone to femoral head AVN or non-union
Treated by hemiarthroplasty = young patients or undisplaced fractures may be fixed with reduction and screw fixation
What are some features of femoral shaft fractures?
Usually high energy and obvious on x-rays
Carry risk of blood loss or fat embolus
What kind of injuries are more common in the knee?
Soft tissue injuries
How is imaging used in knee injuries?
Ct used to clarify fracture anatomy
US and MRI used to assess soft tissue
What do small avulsed bone fragments indicate in the knee?
Significant soft tissue injury
What soft tissue structures are shown by the lateral view of the knee?
Patellar and quadriceps tendons
Suprapatellar fat space
What are significant soft tissue injuries in the knee normally accompanied by?
Effusion = fills the suprapatellar space
What is the standard trauma x-ray taken for the knee?
AP (horizontal beam lateral) = can show lipohaemarthrosis which is a sign of an intra-articular fracture
