patella & patellofemoral joint

Question 1

• prone
• patella parellal with the IR
• head rotated 5 to 10 degree laterally
• CR perpendicular to mid popliteal, exiting patella
• shows patella

Answer 1

PA Projection

Question 2

• lateral recumbent
• flex knee 5 to 10 degree
• increasing flexion reduces patellofemoral joint space
• adjust knee in lateral
• CR perpendicular to IT, entering patellofemoral joint
• shows lateral projection of patella and patellofemoral joint space

Answer 2

Lateral Mediolateral

Question 3

• prone medially rotate the knee 45 to 55 degree
• flex knee approx 5 to 10 degree
• CR perpendicular to IR exiting palpated patella
• shows medial portion of the patella is demonstrated free of the femur

Answer 3

PA Oblique Medial

Question 4

• Flex knee 5 to 10 deg
• Externally (laterally) rotate knee 45 to 55 deg from prone position
• CR perpendicular to IR, exiting the palpated patella
• shows oblique projection of lateral aspect of the patella free of femur

Answer 4

PA Oblique Lateral

Question 5

• Pt in prone
• Elevate hip of affected side 2 or 3 inches
• Knee slightly flexed appox. 10 deg to relax
• Laterally rotate the knee to 35 to 40 deg from prone
• Rest knee on its anteromedial side
• CR 25 to 30 deg caudad directed to joint space between patella and femoral condyle
• shows slightly oblique PA projection of patella
• with most of patella free of superimposed structure

Answer 5

PA AXIAL OBLIQUE PROJECTION
KUCHENDORF METHOD
lateral rotation

Question 6

• pt in prone
• IR under pt’s knee, flex the affected knee so that the tibia and fibula form a 50 to 60 degree angle from the table
• CR 45 degrees cephalad directed thru the patellofemoral joint
• shows subluxation of the patella and patellar fractures and allows radiologic assessment of the femoral condyle

Answer 6

Hughston Method

Question 6

• Using the “axial viewer” device
• elevate pt’s knees approx. 2 inches to place the femora parallel with the tabletop
• knee flexion to 40 degree
• IR perpendicular to the CR and resting on the pt’s shins approx 1 foot distal to the patellae
• CR perpendicular to the IR approx. 30 degrees caudad from the horizontal plane (60 deg from vertical plane)
• CR enters midway bet. patellae and the lvl of patellofemoral joint
• bilateral tangential image demonstrate an axial projection of the patellae and patellofemoral joints

Answer 6

Merchant Method

Question 7

• pt in prone
• flex knee as much as possible or until patella is perpendicular to the IR
• If pt is seated on radiographic table, hold the IR
• CR Perpendicular to the joint space between the patella and the femoral condyles when the joint is perpendicular
• degree of CR angulation depends on the degree of flexion of the knee, typically 15 to 20 degrees
• shows vertical fractures of bone and the articulating surfaces of the patellofemoral articulation

Answer 7

Settegast Method