IMAGING features in knee

1. z
X-ray Knee joint
Dr. Athul.D
JR MDRD

2. z
Anatomy of knee joint
is a synovial hinge joint formed between
three bones:

3. z
Ligaments

4. z
Views of knee joint
 AP view
 Lateral view
 Intercondylar view
 Skyline view/sunrise view

5. z
AP VIEW
Patient Position: Supine
or upright. Internally
rotate the leg slightly (5°)
so that the knee is in a
true AP position.
Kvp: 60
5 degree cephalad tube
tilt
CR:1 cm inferior to the
patellar apex because
the joint space lie 1cm
inferior .

6. z In AP View
 The medial and lateral margins of
the femoral condyles and
opposing tibial condyles should
be in vertical alignment.
 The patella should lie centrally
over the distal femur.
 The fibula head is overlapping the
tibial condyle.
 Normal femorotibial joint space -
4 to 6 mm

7. z
X-ray anatomy
1. Femoral shaft.
2. Medial epicondyle.
3. Lateral epicondyle.
4. Medial condyle.
5. Lateral condyle.
6. Intercondylar notch.
7. Intercondylar eminences (tibial spines).
8. Medial condyle of the tibia.
9. Lateral condyle of the tibia.
10. Head of the fibula.
11. Neck of the fibula.
12. Adductor tubercle.
13. Medial joint space.
14. Lateral joint space.
15. Tibial shaft.
16. Patella.

8. z
Specialised projections:
 Weight bearing view
 Rosenburg’s view
 Tibial plateau view
 Varus-valgus stress views
 Internal-external oblique views
 AP tibia-fibula view

9. z Weight bearing view
 Upright AP view
 Single knee-full weight on
the affected side.
 Upright views frequently
identify joint space
narrowing, femorotibial
subluxation and/ or varus–
valgus instability when non-
weight-bearing views appear
normal.

10. z
Rosenburg view
 Upright PA with 10 degree caudal
tube tilt
 Knees flexed to 45 degree.
 Intercondylar notch appears in
this view to show degenerative
sclerosis, cysts, and
osteochondral defects (including
osteochondritis dissecans).

11. z
Tibial plateau view
 Angling the tube 15 degree
cephalad provides tangential
view of tibial plateau.
 Useful in trauma for
depression of the articular
surface and fractures

12. z
Varus valgus stress views
 Femur stabilised by third person
 Studies taken at varus and valgus
 Width of joint space (5-7mm)and
femorotibial shift(<1mm) is assessed.
 As a sign of collateral ligament stability.

13. z
Internal Oblique view
 Leg is rotated
internally by 45 degree
 5 degree cephalad
tube tilt
 Tibiofibular joint well
visualised

14. z
 The medial oblique shows
the tibiofibular joint to
advantage and avulsion
fractures of the head of the
fibula and lateral tibial
condyle
 (Segond’s fracture)

15. z
External oblique view
 Leg is rotated externally by 45
degree
 5 degree cephalad tube tilt
 Femoral condylar surface,tibial
plateau,tibial spines better
visualised.

16. z

17. z
Ap tibia fibula views
 Ankle dorsiflexed
 With ankle malleoli
equidistant from the
film
 Includes both knee
and ankle in the film

18. z
REVIEW OF AP VIEW
Projection Advantage
Weight bearing view To identify joint space narrowing, femorotibial
subluxation & varus–valgus instability
Rosenburg’s view to show degenerative sclerosis, cysts, and
osteochondral defects
Tibial plateau view useful in trauma to investigate depression of
the articular surface and fractures.
Varus-valgus stress views For assessing collateral ligament stability.
Internal-external oblique views shows the tibiofibular joint and avulsion
fractures of the head of the fibula and lateral
tibial condyle
AP tibia-fibula view preferable for including both the knee and
ankle in the field.

19. z
Lateral view
Patient Position:
Lateral recumbent.
Flex the lower leg
about 45° to traction
the patella in place.
5 degree cephalad
tube tilt(true lateral)
CR: 1 cm distal to the
medial epicondyle

20. z
Anatomy in lateral view
1. Anterior intercondylar area.
2. Posterior intercondylar area.
3. Tibial tuberosity.
4. Tibial shaft.
5. Head of fibula.
6. Fabella gastrocnemius
tendon;
7. Patella.
8. Lateral condyle.
9. Femoral shaft.
10. Superior pole, patella.
11. Inferior pole, patella.
12. Infrapatellar fat (Hoffa’s fat-
pad).
13. Suprapatellar fat, femoral
surface

21. z
Anterior and posterior cortex
of patella are prominent
producing trilaminar
appearance

22. z
Insall salvatti index
 Ratio of Patellar tendon
length/patella length
 Range lies between 0.7-1.5
 patella baja: <0.8 (perhaps
<0.74)
 patella alta: >1.2 (perhaps
>1.5)

23. z
Patella baja
 Low lying patella
 Result of quadriceps tendon
rupture
 B for "below" (baja) ,
Patella alta
• High riding patella
• Due to patellar tendon
rupture/
chondromalacia patellae
A for "above" (alta)

24. z
Modified Insall-Salvati ratio
 Also applied on a lateral 30 degree flexed knee
radiograph,
 A: distance from the inferior margin of the patellar
articular surface the patellar tendon insertion
 B: length of the patellar articular surface
 Modified Insall-Salvati ratio = A/B

25. z
The modified Insall-Salvati
ratio is considered normal
around 1.25, abnormal
when >2 which is
considered diagnostic of
patella alta.

26. z
Ludloffs Lucency
 Distinct radiolucency over
the superimposed
condyles-ludloff’s lucency

27. z
Blumensaat’s line
Line through the roof of the
intercondylar notch
• indicating the relative position of the
patella as normally this line
intersects the lower pole of the
patella
• suggesting ACL injury as the normal
ACL Blumensaat angle is ≤15°
• describing the course of an ACL graft
•
• identifying the location of the lateral
femoral condyle sulcus, which
should be within 10mm of the line

28. z

29. z
Parsons Knob
 Third intercondylar
eminence
 Small bony bump
seen anterior to tibial
spine.
 Insertion point of
anterior cruciate
ligament.
 Enlarges with
osteoarthritisDDX – intra articular body
- Intra articular osteochondroma

30. z
Hoffas Fat pad
 infrapatellar fat (Hoffa’s
fatpad), which occupies
the soft tissue below the
patella anteriorly, is
roughly triangular in
shape, is radiolucent

31. z
Due to the imbalance
of forces between
vastus medialis and
lateralis,impingement
of superolateral
aspect of fatpad
occurs.
Anterior knee pain

32. z
Suprapatellar pouch
 Thread like shadow
 Bounded anteriorly and
posteriorly by fat pad
 Thickening of the pouch
is the sensitive sign of
joint effusion.
 10mm pouch thickness
implies 10 ml of joint
fluid.

33. z
Special views in lateral projection
Cross table lateral view
 This cross table lateral view of the knee
is the traditional way of viewing a
lipohemarthrosis of the knee. Here, the
black arrow indicates blood with fat
(white arrow) layering superiorly.
knee is fully extended.
An exposure with the mAs
reduced by at
least 50% and a horizontal
beam may demonstrate a
fat–blood interface effusion
(FBI sign) in the
suprapatellar
pouch as a marker of
lipohemarthrosis

34. z
Tibial tuberosity view
 Slight internal rotation of the tibia by 5° with lowered
kVp and mAs will assist in demonstrating the
anatomic details of the distal patellar tendon,
infrapatellar fat, tendo-osseous junction, and surface
of the tibial tuberosity

35. z
Weight bearing view
The patella is stabilized by use
of a support device and the knee
is flexed to 15° in full weight
bearing; a horizontal beam is
used.
Anterior translation of the tibia by
> 5 mm is a sign of a deficient
anterior cruciate ligament.

36. z
Quadriceps contraction view:
 In cross-table lateral with a horizontal beam. A 30°
knee bolster is placed in the popliteal fossa, a 15-lb
weight suspended from the ankle, and the patient is
instructed to fully extend the knee
 Anterior tibial displacement of > 4 mm is a sign of
anterior cruciate ligament rupture.

37. z
Tunnel view ( notch view, intercondylar fossa
view)
Part Position: (a) Prone The knee is flexed
approximately 45°,
 Kneeling (Holmblad’s view) in kneeling
position and then lean forward so that
the shaft of the femur will form a 25°
angle with the CR
 CR: (a) Prone: the CR is angled 25°
caudad and enters the knee joint at the
popliteal depression. Center film to the
CR.
 (b) Kneeling (Holmblad’s view): no tube
tilt is used and the CR passes through
the knee joint. Center film to the CR.

38. z Normal anatomy
 1. Femoral shaft.
 2. Adductor tubercle.
 3. Medial condyle.
 4. Lateral condyle.
 5. Medial epicondyle.
 6. Lateral epicondyle.
 7. Popliteal groove.
 8. Intercondylar notch.
9. Intercondylar eminences (tibial spines).
10. Medial condyle, tibia.
11. Lateral condyle, tibia.
12. Styloid process, fibula.
13. Neck of fibula.
14. Tibial shaft.
15. Patella.

39. z
uses
 Detection of loose
bodies(joint mice)
 Osteochondritis
Dissecans

40. z
Tangential
(Skyline, Sunrise) Projection
 Tube Tilt: 10° cephalad.
 Patient Position: Prone. The knee is
fully flexed. If the patient is unable to
fully flex the knee, angle the CR
cephalad sot hat a 45° angle exists
between the lower leg and the CR.
 CR: Set the CR between the patella&
the femoral condyles. Center film to
the CR

41. z
 1. Odd facet of the patella.
 2. Medial facet of the patella.
 3. Lateral facet of the patella.
 4. External cortical surface of the patella.
 5. Patella.
 6. Head of the fibula.
 7. Tibiofibular articulation.
8. Patellofemoral articulation.
9. Medial condyle.
10. Lateral condyle.
11. Groove for the popliteus tendon.
12. Intercondylar (trochlear) notch.
13. Medial epicondyle.
14. Lateral epicondyle.
15. Adductor tubercle.

42. z
uses
 This view is particularly useful
for assessing the patella
position (subluxation,
dislocation), patellofemoral
joint pain (chondromalacia,
arthritis), retropatellar surface
(fracture), and depth of the
trochlear groove (dysplasia).

43. z
Review
Projection Advantage
Quadriceps contraction view ACL pathology
Weight-bearing view: Defects of ACL
Tibial tuberosity view patellar tendon, infrapatellar fat & tibial tuberosity
Cross-table lateral Lipo-hemarthrosis
Intercondylar (Tunnel) view intercondylar notch, loose bodies & osteochondritis
Tangential view patella position, patellofemoral joint pain retropatellar
surface (fracture), & depth of the trochlear groove
(dysplasia)

44. z
AP Knee, Fracture of the Tibial
Plateau
 Vertical fractures are visible
through the medial
(arrowheads) and lateral
tibial plateau (arrow). Note
the offset of the lateral
femoral and tibial condyles
owing to fragment
displacement.

45. z
Schatzker classification

46. z
AP Knee, Degenerative Joint Disease.
 The medial
femorotibial joint
space is
decreased, with
osteophytes and
sclerosis of the
femoral and tibial
condylar surfaces

47. z
AP Knee, Osteochondroma of the
Femur.
 A cortical exostosis
projects off of the
distal metaphysis of
the femur. Note its
calcified
cartilaginous cap

48. z
Lateral view pathologies
 Suprapatellar Joint Effusion.
There is a large fluid effusion
in the suprapatellar pouch
(arrows). Note the
preservation of the fat anterior
to the femur, which borders
the posterior border of the
pouch.

49. z
Paget’s Disease of the Patella and
Tibia.
 The patella and tibia are both
increased in density, have
thickened cortices, and are
enlarged.
 Observe the transverse fracture
of the patella.

50. z
Degenerative Joint Disease of the
Patellofemoral Joint.
 The patellofemoral joint space is
decreased in thickness so that there
is almost bone–bone contact
between the patella and the femur.
There has been a mechanical
erosion of the anterior femoral cortex
owing to chronic patella impingement
(arrow).

51. z
Intercondylar (Tunnel), Knee,
Osteochondritis Dissecans
 single loose body is
visible within the
intercondylar notch
(arrowhead). It has
originated from the medial
condyle, where the defect
can be seen (arrow).

52. z
Intercondylar (Tunnel), Knee,
Chondroblastoma.
 well-defined radiolucent lesion is
present within the medial femoral
condyle (arrows). This lesion
 Seen clearly on the intercondylar
view, because the femoral surface
is less tangential to the incident
beam

53. z
Patellar fractures
M.C -Transverse

54. z
Tangential, Patella, Dislocation.
 The patella (P) has dislocated
laterally relative to the femur (F).
There is a small fracture
fragment adjacent to the lateral
femoral condyle (arrows).

55. z
Tangential,
Patella, Osteochondritis Dissecans
 A separating bone fragment is
visible from the retropatellar
surface involving the majority of
the lateral facet and a small part
of the medial facet (arrow).

56. z
Supracondylar fracture

57. z
Segond fracture
 small fragment of bone
avulsed from the lateral
aspect of the tibia

58. z
Sinding-Larsen-Johansson disease
 Lateral radiograph of the right
knee shows fragmentation of the
lower pole of the patella and
significant soft-tissue swelling
associated with calcifications and
ossifications of the patellar
ligament—findings characteristic
of Sinding-Larsen-Johansson
disease

59. z
Osgood-Schlatter disease.
fragmentation of the
tibial tuberosity (arrows)
in association with soft-
tissue swelling (open
arrow)—characteristic
findings in Osgood-
Schlatter disease.

60. z
Chondroblastoma
 radiolucent lesion
located eccentrically
in the proximal
epiphysis of the tibia,
with sharply defined
borders and a thin,
sclerotic margin
(arrows).

61. z
Osteosarcoma
 The sunburst or
perpendicular type of
periosteal reaction on
the AP radiograph of the
distal femur.
Codman triangle
(arrow) is also shown

62. z
Parosteal osteosarcoma.
 This tumor has a
predilection for
the posterior
aspect of the
distalfemur.

63. z
Periosteal chondrosarcoma.
 a parosteal calcified
mass at the medial
cortex of distal femur,
exhibiting chondroid
calcifications.

64. z
Non ossifying fibroma
 A sclerotic border or
narrow zone of
transition from normal
to abnormal bone
typifies a benign lesion,
as in this example of
nonossifying fibroma
(arrows).

65. z Benign fibrous Histiocytoma
a lobulated radiolucent
lesion with a well-defined
sclerotic border, located
eccentrically in the
proximal tibia.

66. z
Olliers disease
 exhibited in extensive
involvement of multiple
bones and ring-like
calcifications in tongues of
cartilage

67. z Hereditary multiple exostoses.
 An anteroposterior
radiograph of both
knees of a 17-year-old
boy shows numerous
sessile and
pedunculated
osteochondromas

68. z
Chondromyxoid fibroma.
 Anteroposterior (A) and lateral (B)
radiographs of the left leg of an 8-year-old
girl
 demonstrate a radiolucent
lesion extending from the
metaphysis into the diaphysis of
the tibia,with a geographic type
of bone destruction and a
sclerotic scalloped border

69. z
 Thank you