Knee & Patella

Knee Technicolor Factors

(AP, Obliques, Lateral)

• SID: 40”

• Collimation Field Size: 10 × 12

• IR Alignment: Portrait

• Grid:

  • Grid or Bucky: > 10 cm

  • Nongrid: < 10 cm

• kVp: 65-80

Knee Technical Factors

(Tunnel)

• SID: 40”

• Collimation Field Size: 8 × 10

• IR Alignment: Portrait

• Grid: Yes

• kVp: 70-80

Patella Technical Factors

• SID: 48” - 72”

• Collimation Field Size: 8 x 10

• IR Alignment: Portrait or Landscape

• Grid: No

• kVp: 70-80

Patient Position for Settegast Method (Sunrise)

• Have patient seated on XR table

• Flex knee to 90°

• Have patient hold cassette against distal femur

CR and Tube Angle for Settegast Method

• CR: Tangential to patellofemoral joint space

• Tube angle: 15° - 20° from lower leg

AP Knee Patient Positioning

• Place patient supine

• Rotate leg internally 3°- 5° for true AP knee

• Tube angle: None for average build

AP Knee CR Position

½ inch distal to apex of patella

AP Oblique Internal Rotation Knee Patient Positioning

• Patient supine

• Rotate leg internally 45°

• Tube angle: None for average patients

CR for AP Oblique Internal Knee

Midpoint of knee at level ½ inch distal to apex of the patella

CR for AP Oblique Knee Lateral (External) Rotation

Midpoint of knee at level ½ inch distal to apex of patella

Tube angle for Lateral Knee

5-7° cephalad

• Short patients w/ wide pelvis: 7-10° cephalad

• Tall patients w/ narrow pelvis: 5° cephalad

Lateral Knee Patient Positioning

• Patient in lateral recumbent with affected side down

• Flex knee 20-30°

• To prevent over-rotation, place opposite limb behind affected limb for support

AP Oblique External Rotation Knee Patient Positioning

• Patient supine

• Rotate leg externally 45°

CR for Lateral Knee

1” distal to medial epicondyle of femur

What is the common name for the Béclère Method?

Tunnel View

What is another name for the Settegast Method?

Sunrise View

Béclère Method (Tunnel) CR

½ inch distal to apex of patella

Béclère Method (Tunnel) Tube Angle

40-45° cephalad (perpendicular to lower leg)

Béclère Method Patient Positioning

• Patient supine

• Flex knee 40-45°

• Adjust IR to center IR to mid knee joint area

CR for Settegast Method

Tangential to patellofemoral joint space

Tube angle for Settegast Method

15-20° from lower leg

Settegast Method Patient Positioning

Seated:

• Patient seated on XR table

• Flex the knee 90°

• Have patient hold cassette against distal femur

In a lateral knee image, what are characteristics of an under rotated knee?

• Knee is too far away from IR

• Fibulas head is too far anterior

In a lateral knee image, what are characteristics of an over rotated knee?

• Knee is too far toward IR

• Fibulas head too far posterior

In a lateral knee image, what are characteristics of an image with no tube angle?

Medial and lateral femoral condyles are not superimposed.

A medial (internal) oblique knee projection shows what in profile?

• Lateral condyle in profile w/o superimposition.

• Opens up tibiofibular joint

A lateral (external) oblique knee projection shows what in profile?

Medial condyle in profile w/o superimposition

Name the projection.

Should it be repeated, if so why?

AP Knee

No

Label the image

A) Femur

B) Patella

C) Lateral femoral epicondyle

D) Intercondylar fossa

E) Intercondylar eminence

F) Femorotibial joint

G) Fibula

H) Tibia

I) Tibial condylar margin

J) Medial femoral epicondyle

Name the projection.

Should it be repeated, if so why?

Lateral Knee

Yes. Patient is not in true lateral.

• Fibular head and tibia are not superimposed.

• Femoral condyles not superimposed

Label the image

A) Femur

B) Patella

C) Intercondylar eminence

D) Tibia

E) Fibular shaft

F) Fibular neck

G) Fibular head

H) Femorotibial joint

I) Femoral condyles

Name the projection.

Should it be repeated, if so why?

Settegast Method or Sunrise View

No.

Label the image.

1. External cortical surface of patella (not needed for practical)

2. Patella

3. Medial facet of patella

4. Lateral facet of patella

5. Median patellar ridge

6. Femoropatellar joint

7. Medial trochlear ridge

8. Trochlear groove

9. Lateral trochlear ridge

What causes superimposition of the femur on a Tunnel View?

• Knee is over flexed

• Tube not perpendicular to the tunnel

Name the projection.

Should it be repeated, if so why?

Béclère Method or Tunnel View

No.

Label the image.

A) Femur

B) Patella

C) Medial femoral condyle

D) Medial & Lateral Tubercles of Intercondylar Eminence

E) Lateral femoral condyle

F) Intercondylar fossa

Name the projection.

Should it be repeated, if so why?

AP Lateral (external) Oblique

No.

Label the image.

A) Femur

B) Patella

C) Medial femoral condyle

D) Lateral femoral condyle

E) Lateral tibial plateau

F) Medial tibial plateau

G) Medial tibial condyle

H) Fibula

I) Tibia

Name the projection.

Should it be repeated, if so why?

AP Internal (Medial) Oblique

No.

Label the image.

A) Femur

B) Patella

C) Medial femoral condyle

D) Medial tibial condyle

E) Tibia

F) Fibula

G) Lateral tibial condyle

H) Intercondylar eminence(s)

I) Lateral femoral condyle

Name the projection.

Should it be repeated, if so why?

Lateral Knee.

No.

Ignoring pathology and other factors - Is the tube angled appropriately in this image?

No. The femoral condyles are not superimposed, indicating no tube angle.

Is the patient in true lateral with proper tube angle? Explain.

True lateral: No. Patient is under rotated. Fibular head too anterior.

Tube angle: No. Femoral condyles not superimposed.

Is the patient in true lateral with proper tube angle? Explain.

True lateral: No. Patient is over rotated. Fibular head too posterior.

Tube angle: No. Femoral condyles not superimposed.