x-ray anatomy knee

Question 1

where is the anterior and posterior components of the fat pad (located behind the quadriceps tendon), divided by?

Answer 1

supra patellar bursa

should measure 5mm or less

Question 2

how does a soft tissue injury affect the supra patellar bursa?

Answer 2

as it is located within joint capsule, it may expand to form a joint effusion (>5mm)

Question 3

if an intra-articular fracture affects the supra patella bursa, what can this cause?

Answer 3

lipoheamarthrosis
(leakage of blood and marrow into joint)
(fat being Lucent floats on top of blood that is radiographically denser0

Question 4

if there is a lipoheamarthorsis seen in the knee, what can be assumed?

Answer 4

that there is an intra-articular fracture

Question 5

if there is patella dislocation, what other bony injury should be scouted for?

Answer 5

avulsion fractures e.g medial patella or lateral femoral condyle

Question 6

how can you identify radiographically if there is the rupture of the infra patellar ligament

Answer 6

there is increase distance b/w inferior pole of patella and tibial tuberosity

(the average distance should be the length of the patella ±20%)

Question 7

what normal variant of the patella can be found not to be mistaken for injury and where is it located

Answer 7

bipartite patella ( unfused secondary ossification centre)

• found supero-lateral aspect of patella

Question 8

what 3 ligaments are responsible for avulsion fracture of tibial plateau

Answer 8

• medial collateral ligament
• anterior/posterior cruciate ligament

Question 9

what method can you use to identify if there is a split/depression fracture of the tibia plateau

Answer 9

• draw straight line from the lateral femoral condyle and extend
• it should not have more than 5mm of the tibia pass the line

Question 10

what is a segond fracture found in the knee and what ligament causes it

Answer 10

avulsion fracture of the lateral tibial plateau

• lateral capsular ligament

Question 11

partial or complete avulsion fractures of the intercondylar eminence/tibial spine are due to which ligaments

Answer 11

anterior (more common) or posterior cruciate ligament

Question 12

fibular head and neck fractures are usually accompanied by lateral tibial plateau fractures or knee ligament injuries (cruciate or collateral)

Question 13

what is osgood-schlatter’s disease and what causes it

Answer 13

osteochondritis of tibial tuberosity

• occurs in adolescents with repeated trauma to knees

Question 14

the normal ossification centre for tibial tuberosity may demonstrate a wide variety of normal variants and is often fragmented. Diagnosis is made clinically and radiography isnt indicated

Question 15

post knee trauma, Pellegrini-stieda syndrome can occur, what is this

Answer 15

calcification of the medial collateral ligament

Question 16

what is synovial osteochondromatosis and what are the radiographic signs

Answer 16

• multiple cartilaginous loose bodies that calcify in synovial of joint
• multiple radiographically dense pieces located in joint area

Question 17

what is diaphysial atlases and radiographic signs

Answer 17

multiple osteochondromas ( an overgrowth of cartilage and bone that happens at the end of the bone near the growth plate) arisen from metaphysical region pointing away from joint.

• long stalks from metaphysical seen growing outwards of joint region

Question 18

how can you identify the difference between a non-ossifying fibroma/ benign lytic lesion and a malignant on in bone

Answer 18

• Benign bone lesions usually have well-defined borders, they do not break the cortex nor are they associated with a soft tissue mass.
• On the contrary, malignant bone lesions usually have ill-defined borders, break the cortex, and associate soft tissue mass.