Knee

Knee angulation: Clinical

• No angle required

• 3 to 5 degrees

  caudad

• 5 to 7 degrees

  cephalad

• 3 to 5 degrees

  cephalad

For true AP Knee. How much should the knee be internally rotated?

• No rotation needed

• 3 to 5 degrees

• 5 to 7 degrees

• 10 degrees

CR direction on AP and Oblique Knees

• Perpendicular

• Knee Joint

• 1/2" above apex

  of patella

• 1/2" below apex

  of patella

Eval Criteria Anatomy: AP Knee

• Distal femur &

  Proximal Tib

  Fib

• Femorotibial

  joint space open

• Proximal femur

• Distal tib fib

Eval Criteria - No rotation: AP knee

• Femoral &

  Tibial Condyles

  symmetric

• Medial half of Fibula

  head superimposed

  by Tibia

• Intercondylar

  intercondylar

  eminence in center

  of intercondylar fossa

• Intercondylar

  intercondylar

  eminence projected

  medially

  of intercondylar fossa

CR angulations per Bontrager

• < 19 cm: 3 to 5 caudad

• 19 to 24 cm: 0 angle

• >24 cm: 3 to 5 caudad

• >24 cm: 3 to 5 cephalad

Eval criteria - Anatomy: Medial Oblique Knee

• Medial & lateral joint

  spaces appear unequal

• Patella superimposing

  medial femoral

  condyle

• Patella superimposing

  lateral femoral

  condyle

• Lateral condyle of

  femur & tibia well

  demonstrated

Eval Criteria: Positioning

• Proximal tibiofibular

  joint space open

• Lateral condyles of

  femur & tibia seen in

  profile

• Fibula head and neck

  without superimposition

• Half of patella seen

  free of superimposition

  by the femur

CR angulation: Lateral Knee

• 5-7 degrees caudad

• 3-5 degrees cephalad

• 5-7 degrees cephalad

• No angle is needed

CR directed:

• 1” proximal to medial

  epicondyles

• Mid Knee

• 1/2” distal to medial epicondyles

• 1” distal to medial

  epicondyles