Knee pathophysiology: fracture and degenerative changes Flashcards
(63 cards)
how do we screen for fractures at the knee?
ottawa knee rules (Sn 98.5%, Sp 48.6%)
Pittsburgh decision rules (Sn 99%, Sp 61%)
what is the criteria for the ottawa knee rules?
> 55 years old
tenderness at the head of fibula
isolated tenderness of patella
inability to flex knee to 90º
inability to walk for weight bearing steps immediately after injury and in the emergency room
what is the Pittsburgh decision rules?
if the MOI was blunt trauma or fall and one of the following:
age <12 y/o or >50 y/o
inability to walk four weight bearing steps in the ER
what are the types of fracture in the knee?
distal femoral shaft
tibial plateau
patella
what is the MOI for a distal femoral shaft fracture?
MVA or fall from great heights
low level force or minor fall
what are the classifications for a distal femoral shaft fracture?
non displaced
impacted
displaced
comminuted
condylar
intercondylar
what is the incidence rate for distal femoral shaft farctures?
97% fractures > 60 years (females 71.6 years > males 44.1 years)
61% fall from standing height
what is a distal femoral shaft fracture?
disruption of the distal femoral shaft; often displaced fracture and/or comminuted (spiral, transverse, oblique)
may lead to massive internal hemorrhage -> shock
what is the clinical picture for a distal femoral fracture?
grossly swollen, deformity apparent, often unstable
what is the non-operative management for distal femoral fractures?
fewer risks than surgical management however length of time for healing/recovery is much greater
continuous skeletal traction followed by 3-6 weeks of casting
what is the operative management for distal femoral fractures?
internal fixation- use of large intramedullary nail to stabilize fracture site
may utilize an open (ORIF)
what are some complications of distal femoral fractures?
mal-union (rotated or shortened limb)
joint and or soft tissue adhesions
post traumatic DJD
what percent of overall fractures do proximal tibia fractures contribute to?
1%
what is the MOI for proximal tibia fractures?
impact with automobile fenders (25%)
axial loading as a result from a fall
individuals with osteoporosis (8% of all fractures in older individuals)
what is the clinical picture for proximal tibia fractures?
knee effusion, pain, joint stiffness
what are some complications of proximal tibia fractures?
intra-articular and peri-articular adhesions and DJD
where do proximal tibia fractures typically occur in adults?
at medial and lateral tibial plateau in individuals 40-60 years
what is the MOI for adult proximal tibia fractures?
valgus or varus force with axial compression
car pedestrian accident bumper -> knee
elderly with osteoporosis after twisting
where do proximal tibia fractures typically occur in chidlren?
in epiphyseal growth plate and metaphyseal region (3-6 years)
what is the MOI for children proximal tibia fractures?
fall
varus/valgus force with axial load
what are the imaging options for proximal tibial plateau fractures?
x ray (AP, lateral, and oblique views- parfaot sign)
CT may be indicated to determine extent of fracture line
MRI indicated if associated with suspected ligament injury
what is the pathophysiology for proximal tibial plateau fractures?
may see a split (younger) or a depression fracture (older)
more common lateral plateau
may also contribute to ACL tear
at what age range do patellar fractures generally occur in males and females?
males 10-19 years
females 60-80 years
what is the MOI for patellar fractures?
direct: fall (crush fracture)
indirect: jumping (avulsion fracture)
stress fracture
