RADIOGRAPHY OF THE KNEE, PATELLA, and FEMUR

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Barnard Robbins
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1 RADIOGRAPHY OF THE KNEE, PATELLA, and FEMUR

2 KNEE AP Projection Patient Position: Part Position: Leg in Center Femoral condyles

3 Central Ray: - Asthenic patient - if ASIS to tabletop is < 19 cm Sthenic patient if ASIS to tabletop is cm Hypersthenic patient if ASIS to tabletop is > 24 cm Note: CR is

4 Structures Shown:

5 Criteria of Evaluation: The femoral condyles should be The intercondylar eminences should be centered within the. The knee joint Intercondyloid fossa should be The head of the fibula should. The patella should be seen in the.

6 AP knee Error rotated causes lateral condyle to appear, intercondyloid fossa will be, and there will be. Correction - rotate leg. Good image

7 AP knee Error: Knee is this will cause the medial condyle to appear, the intercondyloid fossa will be, and there will be. Correction: rotate leg.

8 AP knee Error causes to be opened too much and the femur is. To correct:. Good image Correction - Fully extend knee if patient is able

9 KNEE AP Oblique Projection Medial (Internal) Rotation Patient Position: Part Position: Leg rotated Center

10 Central Ray: Asthenic patient - if ASIS to tabletop is < 19 cm Sthenic patient if ASIS to tabletop is cm Hypersthenic patient if ASIS to tabletop is > 24 cm

11 Structures Shown: Criteria of Evaluation The head of the fibula should be seen The lateral condyle should. The patella

12 Internal (medial) oblique knee- Error rotation causes the head of the fibula to be from the tibia. Correction -Oblique leg. (needs rotation) Good image

13 AP Oblique Projection Lateral (External) Rotation Structures shown;

14 External (lateral) oblique knee Error will cause the fibula to not be Good image Correction - Oblique leg. Needs more rotation.

15 Patient Position: KNEE Lateral Projection Part Position: Knee flexed Patella to IR Femoral condyles

16 Central Ray: through knee joint (due to femoral condyle, plus it is at a lower level than the femoral condyle) Center epicondyle

17 Note: If patient unable to turn into lateral position, may be obtained

18 Structures Shown:

19 Criteria for Evaluation The distal articulating surfaces of the medial and lateral femoral condyles should be, and the knee joint space should. Determine if CR needs to be angled based on. Wide pelvis angle degrees. Narrow pelvis use angle.

20 Criteria for Evaluation The patella should be situated. The patellofemoral joint should. The tibia should be over the fibular head. Patella seen

21 Lateral Knee Error Knee is flexed the patellofemoral joint. Correction flex knee Good image

22 Lateral Knee Knee is the patellofemoral joint. Correction flex knee. Good image

23 Lateral knee Error - the patella was situated too ( -rotated knee). The head of the fibula is than normal. Correction roll the patella ( ) to the IR.

24 Lateral knee Error - the patella was situated too ( -rotated knee). There is. Correction - roll the patella ( ) from the IR and/or

25 Lateral knee Error. Note that medial femoral condyle. To correct.

26 Lateral knee, patella to IR, and. Correction: roll the patella the IR and have.

27 Case Study

28 Weight-Bearing Knees AP Projection For studies to show Note: CR is

29 Weight-Bearing Knees Lateral Projection For Note: CR is

30 PA Axial Bilateral Weight-Bearing Knees Rosenberg Method For studies to show narrowing of

31 INTERCONDYLAR FOSSA Tunnel Views Camp Coventry Method Homblad Method Beclere Method

32 PA Axial Projection Camp-Coventry Method Patient Position: Part Position: Knee of leg Foot

33 Central Ray: to through knee joint

34 Patient Position: PA Axial Projection Homblad Method Part Position: Knee Knee joint Femoral shafts Central Ray: to through ( knee joint)

35 Holmblad Method Modifications

36 Holmblad Method Modifications

37 AP Axial Projection Beclere Method Patient Position: Part Position: Knee flexed IR placed No Central Ray: Perpendicular to Angled through knee joint Enters

38 Structures Shown:

39 Criteria for Evaluation: Open Knee joint space Apex of patella of femoral condyles

41 Patient Position: PATELLA PA Projection Part Position: Center IR to Rotate heel laterally to make patella to IR (or of anterior knee) Central Ray: to IR Enters ; exits

42 Structures Shown: NOTE: May be done, but detail better when done

43 Stellate Fracture of Patella

44 Patient Position: PATELLA Lateral Projection Part Position: Turn on to Knee flexed Patella is to IR Femoral condyles

45 Central Ray: to IR joint Structures Shown:

46 Transverse Fracture of Patella

47 PATELLA Sunrise or Skyline Views Merchant Method Hobbs Method Settegast Method Hughston Method

48 Bilateral Tangential Projection Merchant Method image ( projection) of both ; shows of patellae

50 Alternative method Hobbs Modification

51 Patient Position: Tangential Projections Settegast Methods Part Position: knee to place patella to IR Base of to IR

52 Settegast Method Modifications

53 Central Ray: to femoro-patellar joint space Angle depends on Structures Shown:

54 Tangential Projection Hughston Method Knee flexed from IR; CR angled Demonstrates

55 Tangential Patella error flexion of knee, patella superimposed on, joint space is. To correct flexion of knee or make the CR.

57 Trauma Radiography of the Patella Sequence of Radiographs shows shows Tangential shows * *Note: Acute flexion of knee should not be attempted

58 FEMUR AP Projection Patient Position: Part Position: Center of IR Rotate leg for distal femur (femoral condyles to IR); for proximal femur (femoral neck to IR)

59 Part Position (Cont d): For distal femur Bottom of IR is For proximal femur Top of IR at the Central Ray: to IR at midfemur

60 Structures Shown:

61 Criteria for Evaluation: Proximal femur Greater trochanter seen Femoral neck Lesser trochanter Distal femur No

62 AP s

63 Patient Position FEMUR Lateral Projection Femur Affected knee

64 Part Position: For distal femur Draw upper leg Pelvis true Patella and femoral condyles to IR Bottom of IR

65 Part Position: For proximal femur Upper leg drawn Pelvis rotated from lateral to prevent joint Top of IR at

66 Central Ray: to IR Structures Shown:

67 Criteria for Evaluation Proximal femur Lesser trochanter Greater trochanter Unaffected femur

68 Criteria for Evaluation Distal femur Anterior surface of femoral condyles Patella in Patellofemoral joint

69 Laterals

70 Trauma Lateromedial projection of Femur

71 Image Stitching

72 CT- Scanograms-Lower CT Scanograms Extremity Take CT Scout images of the femur/tibia For lower extremity measurements Place cursors over the respective hip, knee and ankle joints

73 Situation: A radiograph of a lateral projection of the patella reveals that the femoropatellar joint space is not open. The patella is within the intercondylar sulcus. Solution: The most likely cause of this is excessive of the knee.

74 Situation: A radiograph of an AP knee reveals rotation with almost total superimposition of the fibular head and the proximal tibia. Solution: To correct this positioning error on the repeat exposure, the technologist must rotate the knee slightly.

75 Situation: A radiograph of a PA axial projection for the intercondylar fossa does not demonstrate the fossa well. It is foreshortened. The following positioning factors were used: patient prone, knee flexed 40 to 45, CR angled to be perpendicular to the femur, 40-inch SID, and no rotation of the lower limb. Solution: To correct this positioning error on the repeat exposure, the technologist must direct the CR perpendicular to the to produce a more diagnostic image.

76 Situation: A patient comes to the radiology department for a knee study with special interest in the region of the proximal tibiofibular joint and the lateral condyle of the tibia. Solution: The positioning routines should include, oblique of the knee.

77 Situation: A geriatric patient comes to the radiology department for an intercondylar fossa study of the knee. The patient is unsteady and unsure of himself. Solution: If choosing between the Holmblad or the Camp-Coventry methods, the intercondylar fossa projection might provide the best results without risk of injury to the patient.

78 Situation: A patent enters the ER with a possible transverse fracture of the patella. Which projection(s) would safely confirm a transverse fracture without flexing the patient s knee? Solution: and

79 Situation: On a lateral knee radiograph, if there is increased separation of the tibia & fibula, the knee is -rotated. Solution: The patient must be rotated.

80 Situation: On a lateral knee radiograph, if the head of the fibula is more superimposed on the tibia than normal, the knee is -rotated. Solution: The patient must be rotated.

Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.

RA202 positioning class three- EXM Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. Which of the following hand projections would be used