Knee

Question 1

Assess AP knee image

• (tibial plateau #?)
• (patella?)

Answer 1

• vertical line drawn down the lateral aspect of the lateral femoral condyle should not have more than 5mm of the lateral aspect of the lateral tibial condyle; if there is there could be a tibial plateau #
• bipartite patella is common resulting from unfused ossification sites. Small unfused centre will be well corticaed. Normally located superiolaterally

Question 2

Assess lateral knee image

• (patella?)
• (sesmoids?)

Answer 2

• distance from tibial tubercle to apex of the patella should be the same size as the patella itself: if not, paterllar ligament could be ruptured
• fabella is a common sesmoid bone in the gastrocnemius (can sit very laterally and seen on an AP, can also be bipartite)

Question 3

NAME THE PATHOLOGY

sof tissue calcification adjacent to the medial femoral epicondlye

Answer 3

• pellegrini-stieda lesion

- represents calcifcatio nof an old sprain of the medial collateral ligament

Question 4

What is a lipohaemarthrosis?

Answer 4

• a fat-fluid level seen on a lateral knee x-ray (HBL only)
• effusion in the suprapatellar bursa containing fat released from the bone marrow sitting ontop of a blood fluid level
• seeing a lipohaemarthrosis is indicative of a intra-articular #
• black on top of white

Question 5

Cruciate ligament injury

- (lateral capsular sign/segond #?)

Answer 5

• rupture of a cruciate ligament is occassionally accompanied by a #
• segond # is a small avulsion # of the lateral aspect of the tibial plateau = this has a strong association with a tear of the anterior cruciate ligament

Question 6

Tibial plateau #

• (evidence of an impacted #?)
• (displacement?)

Answer 6

• most involve the lateral plateau
• usually seen as a depression from violent impaction of the lateral femoral condyle - car bumper #

Evidence of an imapcted #: area of increased denisty due to bone compression

The lateral tibial plateau may be displaced, use vertical guide - more than 5mm = displacement

Question 7

Patella

- (violent contraction of quad?)

Answer 7

• direct blow to the patella can cause a #, vertical, horizontal or comminuted
• violent contractions of the quadricep can casue transverse # in athletes
• certical # may not be seen on standard views, skyline may be required

Question 8

Ostechondral # of an articular surface

Answer 8

• a complication of patellar dislocation resulting from shearing or impaction
• this involves the medial surface of the patella or the lateral femoral condyle

Question 9

NAME THE PATHOLOGY
# of the proximal 1/3 of the fibula with associated with an unstable ankle #

Answer 9

maisonneuve ‘

Question 10

AP knee positioning

Answer 10

• patient is standing, back against the detector, leg is rotated either internally or externally until the patella sits centrally.
• centre 1cm distal of the apex of the patella
• collimate to include lateral skin margins, distal 1/3 of femur, proximal 1/3 of tib/fib
• no grid
• 60kVp 4mAs

Question 11

Lateral knee positioning

Answer 11

• patient turns so the affected side is closest to the board, affected knee is bent and central of the image detector, patient takes a step back with unaffected leg
• femoral condyles should be superimposed
• centre 1.5 cm distal of the apex of the patella, over the knee joint
• no grid
• 60kVp 4mAs

Question 12

Horizontal beam lateral knee

Answer 12

• patient lies supine, triangle pad placed under affected knee, IR placed between patients legs, facing affected knee.
• tube is perpendicular to the detector, parallel to the floor
• centre 1.5cm below apex of patella, or level of tibial tuberosity
• 60kVp 4mAs
  ASSESS FOR LIOPHAEMARTHROSIS