Knee

Define the Posterior Cruciate & Anterior Cruciate and role?

-Ligaments related to the knee joint that crisscross and stops movement from anterior to posterior

Define the Fibular (lateral) collateral & Tibial (medial) collateral and role?

-Ligaments related to the knee joint that are on the sides and help stop movement side to side

Define Meniscus and role?

There is a medial and lateral menisci located between the articular facets of the tibia, act as a shock absorber to reduce direct impact at the knee joint

Proximal Tibiofibular joint movement?

Gliding

Femorotibial joint movement?

Bicondylar/Hinge

Patellofemoral joint movement?

Saddle

Technical Considerations

Grid- if knee measures more than 10 cm

Nongrid = 65-75 kvp

Grid= 70-80 kvp

SID = 40 inches

Small FSS

AP knee

CR = ½ inch distal to apex of patella, parallel to tibial plateaus

• Medial rotate leg 5 degrees to get true AP, condyles parallel to IR

• Angle rules: 18 cm → 5 degrees caudal, 19-24 cm→ no angle, 25cm→ 5 degrees cephalic

• Why angle? to get perpendicular to the tibial plateau/ femorotibial joint space

-Femorotibial joint space open

-Fibular head superimposed by the tibia

-Patella in middle of femur

-Intercondylar eminence in middle of condyles

AP Medial/Internal Oblique Knee

CR= ½ inch distal to apex of patella

No tube angle

45 degree medial rotation

-Tibia and fibula seperated

-Proximal tibiofibular joint seen

-Lateral condyles in profile

AP Lateral/External Oblique Knee

CR= ½ inch distal to apex of patella

No tube angle

45 degree lateral rotation

-Fibula superimposed by tibia

-Medial condyles in profile

Lateral knee

CR = 1 inch distal to medial epicondyle

Flex knee 20-30 degrees (not on cross table)

Angle 5-7 degree cephalad to compensate for medial condyle

-Femoral condyles superimposed

-Patella in profile

-Patellofemoral joint space open

-Tibial tuberosity in profile

What projection?

Label?

Lateral knee

1. Femur

2. Superimposed medial and lateral condyles

3. Fibular head

4. Fibula

5. Femoropatellar joint

6. Intercondylar eminence

7. Tibia

Is this under or over rotated?

How to correct it?

Over rotated - Fibula away from tibia, medial condyle more anterior

-Correction= roll patient knee away from IR

Is this under or over rotated?

How to correct it?

Under rotation = Fibula covered by tibia, medial condyle more posterior

Correction= Roll patient knee towards IR

Special - AP Weight Bearing

Special - PA Axial weight bearing = Rosenberg

Bilateral AP + Lateral

To evaluate joint space = Femorotibial joint space

No tube angle on lateral weight bearing

-Knee joints centered

-No rotation of knee

-Joint spaces open = Femortibial joint space

Camp Coventry method

Flex lower leg 40-50 degrees

CR= Perpendicular to lower leg (angle 40-50)

CR= popliteal crease

-Intercondylar fossa in profile

-Articular facets and intercondylar eminence well visualized

Holmblad Method

Lean forward 20-30 degree, leg forms 70 degree angle

CR= perpendicular to lower leg (no angle)

CR = popliteal crease

-Intercondylar fossa in profile

-Articular facets and intercondylar eminence well visualized

AP Axial - Beclere method

Knee flexed 40 to 50 degrees

CR = perpendicular to lower leg (angle)

CR= ½ inch distal to apex of patella

-Intercondylar fossa in profile

-Articular facets and intercondylar eminence well visualized

Projection?

Label?

Incondylar fossa

1. Medial femoral condyle

2. Intercondylar fossa

3. Patella

4. Lateral femoral condyle

5. Articular facet

6. Articular facets

7. Intercondylar eminence

8. Tibia

9. Fibular head

PA Patella

CR = Perpendicular to mid patella area (popliteal crease)

Rotate knee 5 degrees medial for true AP

-Patella centered to collimation field

Mediolateral Patella

CR= to patellofemoral joint space

Flex only 5-10 degrees

-Patella and knee joint in center of collimation field

-Patella in true lateral = in profile

Tangential (superior- inferior) merchant bilateral method

Knee flexed 40 degrees

CR angled 30 degree from horizontal

-Intercondylar sulcus and patella visualized

-Patellofemoral joint spaces open

Projection?

Label?

Tangential patella - merchant method

1. Femoropatellar joint space

2. Intercondylar sulcus (trochlear groove)

Inferosuperior projection

40-45 degrees flexion of knees

CR - tangential to femoropatellar joint

Hughston method - Inferior to superior

Knee flexed 50- 60 degrees

CR - tangential to patellofemoral joint space

Looks at patella

Settegast Method (inferosuperior)

90 degree flexion (tangential to femoropatellar joint space)

CR- tangential to femoropatellar joint space

Looks at patella

Gout

a form of arthritis that may be hereditary in which uric acid appears in excessive quanities in the blood, very common in the first MTP of foot

Osteomyelitis

a bone infection that can result from bacteria or fungi spreading through the bloodstream or from an injury that directly exposes the bone to germs

Osteomalacia (Rickets)

Bone softening, disease caused by lack of bone mineralization. known as rickets in children and commonly results in bowing of the tibia

Osgood-Schlatter disease

Inflammation of the bone and cartilage of the anterior proximal tibia, most common in boys 10 -15, detaches part of the tibial tuberosity

Osteochondroma

Benign, neoplastic bone lesion that is caused by consolidated overproduction of the bone at a joint, usually the knee

Torn menisus/ACL

a common knee injury where the anterior cruciate ligament and the meniscus cartilage are both damaged

Flat foot

a common condition where the arches on the inside of your feet flatten, causing the entire sole to touch the ground when standing

-Reason why we do weightbearing foot