Chapter 7 Part 1- Knee, Patella, Femur
What are some evaluation criteria for the AP Femur?
-Most of the femur and the joint nearest to the pathologic condition or site of injury (a second projection of the other joint is recommended) -Femoral neck not foreshortened on the proximal femur -Lesser trochanter not seen beyond the medial border of the femur or only a very small portion seen on the proximal femur -No knee rotation on the distal femur -Gonad shielding when indicated, but without the shield covering the proximal femur -Any orthopedic appliance in its entirety
What are the evaluation criteria for the Lateral Femur(it's a lot)?
-Most of the femur and the joint nearest to the pathologic condition or site of injury (a second radiograph of the other end of the femur is recommended) -Any orthopedic appliance in its entirety -Bony trabecular detail and surrounding soft tissues With the knee included: ---Superimposed anterior surface of the femoral condyles ---Patella in profile ---Open patellofemoral space ---Inferior surface of the femoral condyles not superimposed because of divergent rays With the hip included: -Opposite thigh not over proximal femur and hip joint -Greater trochanter superimposed over distal femoral neck -Lesser trochanter visible on medial aspect of proximal femur
What are some evaluation criteria for the Intercondylar Fossa Method for the knee?
-Open intercondylar fossa -Posteroinferior surface of the femoral condyles -Knee joint space open, with one or both tibial plateaus in profile (superimposed anterior and posterior surfaces) -Apex of the patella not superimposing the fossa -No rotation, demonstrated by slight tibiofibular overlap and centered intercondylar eminence
What are some evaluation criteria for the PA Patella?
-Patella completely superimposed by the femur -No rotation
What is demonstrated on the Tangential Projection Settegast Method of the patella?
-Patella free from superimposition on the femur
What are some evaluation criteria for the Tangential Projections of the patella?
-Patella in profile -Femoral condyles and intercondylar sulcus -Open patellofemoral articulation
What is demonstrated on the Tangential Projection Merchant Method of the patella?
-Patellae in profile -Femoral condyles and intercondylar sulcus -Open patellofemoral articulation
Describe the patient, part, and CR position for the PA Patella
-Patient is prone with knee extended to reduce magnification and improved sharpness -True PA with patella parallel to IR; possible 5-10 degree lateral rotation of heel - CR is perpendicular to the midpopliteal area, exiting the patella
Describe the patient, part, and CR position for the Lateral Femur
-Patient is recumbent lateral lying on affected side; drawn unaffected leg in front of or behind the affected side -Flex knee and place femoral condyles perpendicular to the IR; long axis of femur parallels edge of IR ---Knee: Place IR about 2" inferior to knee joint ---Hip: Place top of IR at ASIS -CR is perpendicular to IR, centered to midshaft; include knee on distal portion of radiograph.When including the hip, may need a10-15 degree cephalic angle.
Describe the patient, part, and CR position for the Tangential Projection Settegast Method of the patella
-Seated on the x-ray table with knees flexed. IR placed against the lower thighs OR prone with knee flexed. Prone will allow patient to flex at a greater angle. -True AP with knee flexed about 45 degrees. Patella will be perpendicular with IR -Perpendicular to joint space between patella and femoralcondyles. Typical angle is 15-20 degrees, however, will depend on when the joint is perpendicular to IR
Describe the patient, part, and CR position for the Tangential Projection Merchant Method of the patella
-Seated with both knees at the end of the table. Legs will be hanging off the table onto the Merchant device. -Elevate knees about 2 inches using positioning devices. Femur will be parallel with table. Knee flexed about 40 degrees, which could vary. Using the strap for stability. -Perpendicular with IR. CR enter midway between the patellae at the level of the patellofemoral joint.
Describe the patient, part, and CR position for the AP Femur
-Supine with knee fully extended -Rotate entire lower extremity 10-15 degrees internally; long axis of femur parallels edge of IR ---Knee: Place bottom of IR 2" below knee joint ---Hip: Place top of IR at ASIS -Perpendicular to the midfemur and the center of the IR
List and describe the 2 parts of the femur that form parts of the hip and knee joints
1. Shaft/body-- mid part of the femur 2. Patellar surface-- smooth, triangular shaped depression at the distal femur that is located under the patella
The angle between the medial and lateral condyles is about...
10 degrees from horizontal (angle variation in adults)
<19 cm ASIS/TT measurement calls for what amount of angulation?
3-5 degrees caudal
>24 cm ASIS/TT measurement calls for what amount of angulation?
3-5 degrees cephalic
What's the SID and IR size for the AP Knee?
40" and 10 x 12
What's the SID and IR size for the PA Axial Intercondyloid Fossa?
40" and 10 x 12
What's the SID and IR size for the AP Femur?
40" and 14 x 17
What's the SID and IR size for the PA Patella?
40" and 8 x 10
What's the SID and IR size for the Tangential Projection Settegast Method of the patella?
40" and 8 x 10
What is the point of attachment for the tendon of the adductor muscle on the posterior and lateral area of the medial condyle?
Adductor tubercle
What is demonstrated on the Tangential Projection Merchant Method of the patella?
Bilateral patella free from superimposition on the femur, and bilateral patellofemoral joint
What pathology is demonstrated on the PA Axial Intercondyloid Fossa-Camp Coventry Method?
Bony or cartilage injuries to condyles, tibia plateau and intercondyloid regions
What are the 2 rounded processes on the back of the distal femur? Which one is lower than the other?
Condyles-the medial condyle
What is demonstrated on the Lateral Femur?
Distal 2/3 of femur; knee not in true position due to divergent ray. May require another exposure for hip (depends on protocol)
What is demonstrated on the AP Femur?
Entire femur, include both joints (depends on protocol-depending on length of patient's femur, two images may need to be taken so the knee joint is included)
What is the strong, pyramid shaped process inferior to the femoral head that connects the head to the body/shaft?
Femoral Neck
What forms the knee joint?
Femoral condyles and the tibial plateaus
What is the longest and strongest bone of the body? What's the classification of this bone?
Femur-Long bone
What pathology is demonstrated on the AP Femur?
Fractures or bony lesions
What pathology can be demonstrated on the AP Knee?
Fractures, lesions or bony changes such as arthritis
What pathology is demonstrated on the Lateral Knee?
Fractures, lesions, and bony changes such as arthritis
What pathology is demonstrated on the AP Medial Oblique Knee?
Fractures, lesions, bony changes such as arthritis
What is the large prominent process on the lateral femur?
Greater trochanter
What part of the femur articulates with the acetabulum of the pelvis to form the hip joint?
Head
What are some other terms for the patellar surface?
Intercondylar surface or trochlear groove
What is demonstrated on the PA Axial Intercondyloid Fossa?
Intercondyloid fossa with superimposition of the patella
The long, deep groove between the 2 femoral condyles is called the...
Intercondyloid fossa/notch
What's some evaluation criteria for the AP Weight-Bearing Knee?
Knee is without rotation with the knee joint spaces centered to the exposure area(same for Bilateral WB Knees)
What is demonstrated on the PA Patella?
Knee joint and patella superimposed over the femur
What is demonstrated on the AP Medial Oblique Knee?
Lateral femoral condyles and tibia, proximal tibiofibular joint, head and neck of the fibula without superimposition on the tibia
What's the small, cone shaped process on the medial and posterior side of the femur, just inferior to the neck?
Lesser trochanter
What pathology is demonstrated on the Tangential Projection Settegast Method of the patella?
Linear fractures of the patella, lesions of the patellofemoraljoint
How do you determine the angulation for the AP Knee between different body habitus types?
Measuring between the ASIS and the TT
What are the rough prominences on the lateral and medial surface for attachment of ligaments?
Medial and Lateral epicondyles
19-24 cm ASIS/TT measurement calls for what amount of angulation?
None- Perpendicular
What is demonstrated on the AP Knee?
Open tibiofemoral joint, distal femur and proximal tib/fib
What is demonstrated on the AP Weight-Bearing Knee?
Open tibiofemoral joint, distal femur, proximal tibia and fibula
What pathology is demonstrated on the PA Patella?
Patellar fractures and lesions
What's the joint between the patella and femur called?
Patellofemoral
Describe the patient, part, and CR position for the PA Axial Intercondyloid Fossa
Patient is prone with knee flexed and leg supported below the knee. True PA of knee with femoral epicondyles parallel to IR; knee flexed 40-50 degrees. The tube is angled 40-50 degrees caudal to place central ray perpendicular to long axis of the tibia and fibula; centered to the popliteal fossa, CR should exit the patellar apex
Describe the patient, part, and CR position for the AP Medial Oblique Knee
Patient is recumbent with the knee extended and rotated inward to the unaffected side. The knee is rotated internally to place the femoral inter-epicondylar line 45 degrees to the IR. The CR is perpendicular to the IR for the average patient entering 1/2 inch distal to the patellar apex. The CR can be angled 3-5 degrees cephalad/caudad depending on body habitus
Describe the patient, part, and CR position for the AP Weight-Bearing Knee
Patient is standing with the knee fully extended, weight evenly distributed, and toes pointed straight forward. In true AP position so that the femoral epicondyles are parallel from the IR. The CR is horizontal and perpendicular for the average patient and centered 1/2" distal to the patellar apex
What's the SID and IR size for the AP Weight-Bearing Knee?
SID is 40" and IR size is 14 x 17 crosswise
What type of joint is the Knee? What structures cushion it?
Synovial hinge with bursa or sac-like structures with synovial fluid for cushion
The Femorotibial joint is formed by...
The 2 condyles of the femur with the tibia condyles
What is the name of the thick ridge of bone between the two trochanters?
The Intertrochantereric crest
What are some evaluation criteria for the Lateral Knee?
The knee is flexed 20-30 degrees and in the true lateral position as shown by the femoral condyles superimposed over one another. The fibular head and tibia are slightly superimposed with the patellofemoral joint space open. The joint space between the femoral condyles and the tibia are open
What are some evaluation criteria for the AP Knee?
The knee is fully extended if the patient's condition allows it and it's free of rotation. The femoral condyles are symmetric and the tibial intercondylar fossa is centered. The patella is totally superimposed on the femur and the femorotibial joint space is open.
What is demonstrated on the Lateral Knee?
The knee is in profile to include the tibiofemoral and patellofemoral joints
What is the patella and where is it located?
The largest and most constant sesamoid bone in the body. It's located on the distal and anterior portion of the femur
The Patellofemoral joint is formed by...
The patella with the anterior surface of the distal femur
Describe the patient, part, and CR position for the Lateral Knee
The patient is lateral recumbent on their affected side with their knee flexed slightly. The unaffected knee is either flexed and drawn forward or placed behind the affected knee. Knee is flexed 20-30 degrees and adjusted to be in true lateral. Femoral condyles and patella are perpendicular to the IR and the femoral condyles should be superimposed. The CR is angled 5-7 degrees cephalad and centered 1 inch distal to the medial epicondyle
Describe the patient, part, and CR position for the AP Axial Intercondyloid Fossa
The patient is supine with knee flexed 60 degrees to the long axis of the lower leg. The CR is perpendicular to the long axis of the lower leg, entering the knee joint ½ inch below the patella apex.
Describe the patient, part, and CR position for the AP Knee
The patient is supine with the knee joint fully extended. The knee is in true AP with femoral epicondyles parallel to the IR. The CR is perpendicular to the TT for the average patient or angled depending on ASIS/TT measurement
What is the Popliteal surface?
The posterior aspect of the femur, just above the intercondyloid fossa where the popliteal blood vessels and nerve pass
What are some evaluation criteria for the AP Medial Oblique Knee?
Tibia and fibula are separated at their proximal articulation with the knee joint open. The posterior tibia along with the lateral condyles of the femur and tibia are shown. Both tibial plateaus are seen as well as the margin of the patella projecting slightly beyond the medial side of the femoral condyle
What's the SID and IR size for the Tangential Projection Merchant Method of the patella?
-40" (72" recommended to reduce magnification) -10 X 12 (24 X 30) Crosswise
What pathology is demonstrated on the Tangential Projection Merchant Method of the patella?
-Linear fractures of the patella, lesions of the patellofemoraljoint
