Knee Flashcards
AP view:
- pt position
- central beam
- advantages
- limitations
- pt position - supine with knee fully extended and leg in neutral position
- central beam - directed vertically to the knee 5-7 degree cephalad
- advantages - distal femur, proximal tibia, M/L condyles, M/L tibial spines, M/L joint compartments, M/L tibial plateaus, head of fibula
- limitations - patella not well viewed; superimposed on distal femur
lateral view:
- pt position
- central beam
- advantages
- pt position - flat on same side as affected knee which is flexed 25-30 degrees
- central beam - directed vertically toward the medial aspect of the knee (5-7 degrees) cephalad angulation
- advantages - excellent projection to demonstrate patella-femoral relationship
What should the patella and patellar ligament ratio be?
Length of patella and length of patellar ligament are equal to each other, +/- 20%
Tunnel view:
- pt position
- central beam
- advantages
- pt position - prone with knee flexed approximately 40 degrees
- central beam - central beam is projected caudally toward the knee at 40 degree angle from the vertical
- advantages - posterior aspect of femoral condyles, intercondylar notch, intercondylar eminence, ACL rupture
Sunrise (axial) view:
- pt position
- central beam
- advantages
- disadvantages
- pt position - prone with knee flexed to 115
- central beam - directed at the patella with 15 degrees cephalad angulation
- advantages - femoropatellar joint compartment is well demonstrated
- disadvantages - subtle subluxation of patella may not be demonstrated and effusion may not allow for knee flexion
Merchant (axial) view:
- pt position
- central beam
- advantages
- pt position - supine with knee flexed approximately 45 degrees
- central beam - directed caudally through the patella at 60 degrees from the vertical
- advantages - subluxation of the patella; relation of the patella to the femoral condyles well demonstrated
What two specific measures are obtained from the merchant view?
- sulcus angle = 138, formed by lines extending from deepest point of intercondylar sulcus to the top of the femoral condyles
- congruence angle = -6, bisect sulcus angle, draw second line from Lowes point of articular ridge of patella to deepest point of the sulcus
- Congruence angle of 16 degrees or greater, which is associated with patellofemoral disorders
- additional tangential views at 30, 60, and 90 degrees
What knee injuries are best viewed with AP view?
- medial and lateral joint compartments
- varus and valgus deformity
- Fx of M/L femoral condyles, M/L tibial plateaus, tibial spins, proximal fibula
- Ostechondral fx
- onsteochondritis dessicans
- spontaneous osteonecrosis
- pellegrini-stieda lesion
- bipartite or multipartite patella
- fx of patella
- collateral lig tear
What knee injuries are best viewed with lateral view?
- femoropatellar joint compartment
- patella in profile
- supra patellar bursa
- fx of distal femur, prox tibia, patella
- sinding-larsen-johansson
- osgood-schlatter
- osteochondral fx
- Osteochondritis dissecans
- spontaneous osteonecrosis
- jt effusion
- tears of quad tendon, patellar lig
- cruciate lig tears
- FBI sigh of lipohemarthrosis
What knee injuries are best viewed with tunnel view?
- posterior aspect of femoral condyles
- intercondylar notch
- intercondylar eminence of tibia
What knee injuries are best viewed with axial (sunrise and merchant) view?
- articular facets of patella
- sulcus angle
- congruence angle
- fx of patella
- subluxation and dislocation of patella
What is seen on radiograph that indicates an intraarticular tibial plateau fracture?
FBI sign
- fat blood interface
blood and bone marrow fat endure the joint and produce a characteristic layering of these two on the radiograph
lipohemarthrosis
fragmentation of the lower pole of the patella and significant soft tissue swelling associated with calcification and ossification of the patellar ligament
sinding-larsen-johansson disease
- localized pain of the inferior patellar
apophysitis of tibial tubercle; soft tissue swelling anteriorly
- 3x more frequent in boys than girls
osgood-schlatter disease
